TRUWIZ 122a

September 09 2021: 

                                                      TRUWIZ 122a            

(see also truwiz122b)

trusciencetrutechnology@blogspot.com

Volume 2021, Dated: 09 September 2021 

[Initiated by Prof. Dr. K. Lakshmi Narayana]

In Memory of

Late Professor Kotcherlakota Rangadhama Rao

                                                                     D.Sc. (Madras).a D.Sc. (London).

(Birth on 09 September 1899 Early Morning, Berhampur

Demise on 20 June 1972 at 9 h 09 m at Visakhapatnam),

at his residence, Narasimha Ashram, Official Colony, 

Maharanipeta. P. O., Visakhapatnam 530002.

[Mrs. Peramma Rangadhama Rao demise on 31 Dec 1971 around 10 AM.

at Narasimha Ashram, Official Colony, Maharanipeta.P.O.Visakhapatnam.]

TRUWIZ-122a

Q1. arXiv:2011.09595 [physics.ins-det]: [Submitted on 19 Nov 2020]:  High detection efficiency silicon single-photon detector with a monolithic integrated circuit of active quenching and active reset. Yu-Qiang Fang, et al., ABSTRACT: Silicon single-photon detectors (SPDs) are key devices for detecting single photons in the visible wavelength range. Photon detection efficiency (PDE) is one of the most important parameters of silicon SPDs, and increasing PDE is highly required for many applications. Here, we present a practical approach to increase PDE of silicon SPD with a monolithic integrated circuit of active quenching and active reset (AQAR). The AQAR integrated circuit is specifically designed for thick silicon single-photon avalanche diode (SPAD) with high breakdown voltage (250-450 V), and then fabricated via the process of high-voltage 0.35-μm bipolarCMOS-DMOS. The AQAR integrated circuit implements the maximum transition voltage of ~ 68 V with 30 ns quenching time and 10 ns reset time, which can easily boost PDE to the upper limit by regulating the excess bias up to a high enough level. By using the AQAR integrated circuit, we design and characterize two SPDs with the SPADs disassembled from commercial products of single-photon counting modules (SPCMs). Compared with the original SPCMs, the PDE values are increased from 68.3% to 73.7% and 69.5% to 75.1% at 785 nm, respectively, with moderate increases of dark count rate and after pulse probability. Our approach can effectively improve the performance of the practical applications requiring SPDs of 

                       a. Silicon b. dark count  c. Magnesium   d. Uranium.

Q2. arXiv:2011.10299 [astro-ph.HE]: [Submitted on 20 Nov 2020]: Origin of the UV to X-ray emission of radio galaxy NGC 1275 explored by analyzing its variability. Fumiya Imazato, Yasushi Fukazawa, Mahito Sasada, Takanori Sakamoto. ABSTRACT: We analyze the ultraviolet (UV) and X-ray data of NGC 1275 obtained with {\it Swift}/UVOT, XRT, BAT and {\it Fermi} Large Area Telescope over about 10 years to investigate the origin of the nuclear emission from NGC 1275. We confirm that the UV and soft/hard X-ray fluxes gradually increased along with the GeV gamma rays. At times, short-term variations in the UV or soft X-ray spectral regions showed rapid variations correlated with the GeV gamma-rays. However there was no significant correlation between the UV and soft X-rays. The UV spectrum had a narrow spectral shape that could be represented by single-temperature blackbody radiation. These results could possibly indicate that the long-term variability of UV and X-ray emissions is caused by the jet, while the emissions from the accretion disk contribute to the UV and X-ray bands to some 

                       a. correlation    b. extent     c. radiation   d. shape.

Q3. arXiv:2011.10559 [astro-ph.CO]: [Submitted on 20 Nov 2020]: A look at the Hubble speed from first principles. Fabrizio Renzi, Alessandra Silvestri. ABSTRACT: We introduce a novel way of measuring H0 from a combination of independent geometrical datasets, namely Supernovae, Baryon Acoustic Oscillations and Cosmic Chronometers, without the need of calibration nor of the choice of a cosmological model. Our method builds on the \emph{distance duality relation} which sets the ratio of luminosity and angular diameter distances to a fixed scaling with redshift, for any metric theory of gravity with standard photon propagation. In our analysis of the data we employ Gaussian Process algorithms to obtain constraints that are independent from the underlying cosmological model. We find H0=69.5±1.7 Km/s/Mpc, showing that it is possible to constrain H0 with an accuracy of 2% with minimal assumptions. While competitive with current astrophysical and cosmological constraints, our result is not precise enough to solve the Hubble tension in a definitive way. However, we uncover some interesting features that hint at a twofold solution of the 

                     a. Tension     b. model     c. cosmology    d. assumption.

Q4. arXiv:2011.10561 [astro-ph.GA]: Submitted on 20 Nov 2020: Resolving the Dust-to-Metals Ratio and CO-to-H2 Conversion Factor in the Nearby Universe. I-Da Chiang, et. al. ABSTRACT: We investigate the relationship between the dust-to-metals ratio (D/M) and the local interstellar medium environment at ~2 kpc resolution in five nearby galaxies: IC342, M31, M33, M101, and NGC628. A modified blackbody model with a broken power-law emissivity is used to model the dust emission from 100 to 500 um observed by Herschel. We utilize the metallicity gradient derived from auroral line measurements in HII regions whenever possible. Both archival and new CO rotational line and HI 21 cm maps are adopted to calculate gas surface density, including new wide field CO and HI maps for IC342 from IRAM and the VLA, respectively. We experiment with several prescriptions of CO-to-H2 conversion factor, and compare the resulting D/M-metallicity and D/M-density correlations, both of which are expected to be non-negative from depletion studies. The D/M is sensitive to the choice of the conversion factor. The conversion factor prescriptions based on metallicity only yield too much molecular gas in the center of IC342 to obtain the expected correlations. Among the prescriptions tested, the one that yields the expected correlations depends on both metallicity and surface density. The 1-σ range of the derived D/M spans 0.40-0.58. Compared to chemical evolution models, our measurements suggest that the dust growth time scale is much shorter than the dust destruction time scale. The measured D/M is consistent with D/M in galaxy-integrated studies derived from infrared dust emission. Meanwhile, the measured D/M is systematically higher than the D/M derived from absorption, which likely indicates a systematic offset between the two 

            a. formulations  b. approaches.  c. destructions  d. methods.

Q5. arXiv:2011.10168 [gr-qc]: Submitted on 20 Nov 2020: Curvature profiles for quantum gravity. J. Brunekreef, R. Loll. ABSTRACT: Building on the recently introduced notion of quantum Ricci curvature and motivated by considerations in nonperturbative quantum gravity, we advocate a new, global observable for curved metric spaces, the curvature profile. It is obtained by integrating the scale-dependent, quasi-local quantum Ricci curvature, and therefore also depends on a coarse-graining scale. To understand how the distribution of local, Gaussian curvature is reflected in the curvature profile, we compute it on a class of regular polygons with isolated conical singularities. We focus on the case of the tetrahedron, for which we have a good computational control of its geodesics, and compare its curvature profile to that of a smooth sphere. The two are distinct, but qualitatively similar, which confirms that the curvature profile has averaging properties which are interesting from a quantum point of 

                          a. analysis  b. view  c. control   d. similarity. 

Q6. PDF available: Neutrino versatile, Quantum Mechanical Creatures, Water and Mrs. Peramma Rangadhama Rao’s conjecture of human birth and other life in Meteors and Meteoroids. trusciencetrutechnology@blogspot.com Prof. Dr. Kotcherlakota Lakshmi Narayana, 17-11-10, Narasimha Ashram, Official Colony, Maharanipeta.P.O., Visakhapatnam 530002, AP. Mobile No. 9491902867. Neutrinos, they are very small. They have no charge and have no mass, And do not interact at all, The Earth is just a silly ball, To them, through which they simply pass, Like dust maids down a drafty hall, Or photons through a sheet of glass, They snub the most exquisite gas, Ignore the most substantial wall, Cold-shoulder steel and sounding brass, Insult the stallion in his stall, And scorning barriers of class. ABSTRACT: It was first suggested by Mrs. Peramma Rangadhama Rao in the possible years 1950-1980 that meteorites carry with them the livingness and when struck on Earth they give rise to birth of extraordinary creatures and human beings. Brighter meteorites produce intelligent and inventive personalities. A meteorite is the remains of a meteoroid that has survived the ablation of its surface material during its passage through the atmosphere as a meteor and has impacted the ground.  Some of these meteorites are from beyond the Milky way and perhaps even remote galaxies, which number multitude. This suggests that the livingness, in my opinion, is far beyond human comprehension. Quantum Mechanical creatures is a solid suggestion of the present author. They exist in a variety of forms and in both on land and in the oceans, and far away galaxies etc., scientists discovering them is very fascinating. Creatures that change color on different occasions of danger or otherwise definitely sound Quantum Mechanical

                   a. devices.    b. grounds.    c. manifestations.   d. fascinations.

Q7. PDF available: Klanion formulation of Ramanujam’s Fractional Calculus To describe Particles and Fields. by Prof. Dr. Kotcherlakota Lakshmi Narayana.                    trusciencetrutechnology@blogspot.com 17-11-10 Narasimha Ashram. Official Colony, Maharanipeta.P.O. Visakhapatnam 530 002. Andhra Pradesh.  ABSTRACT: The Klanion Formulation of Ramanujam’s Fractional Calculus to describe Particles and Fields is an amazing enumeration that vividly projects the Axigra. The Axigra is a combination of Axion plus the Gravitin. We take mA as the mass of Axigra. Klanion is explicitly written down. Ψ̅    and  Ψ  stand for Dirac Fields and N as a normalization factor and me the mass of Electron. The variations with respect to Ψ̅   and   Ψ are made with Euler-Lagrange equations and, two equations we obtained are of immense use. The main equation for Axigra employs only one-fourth order of differentiation for 

                                       a. "A".      b. N       c.  Ψ       d. mA 

Q8. arXiv:2011.12359 [cond-mat.mes-hall]: Submitted on 24 Nov 2020:  Inkjet printed circuits with two-dimensional semiconductor inks for high-performance electronics. Tian Carey, et al., ABSTRACT: Air-stable semiconducting inks suitable for complementary logic are key to create low-power printed integrated circuits (ICs). High-performance printable electronic inks with two-dimensional materials have the potential to enable the next generation of high performance, low-cost printed digital electronics. Here we demonstrate air-stable, low voltage (< 5 V) operation of inkjet-printed n-type molybdenum disulfide (MoS2) and p-type indacenodithiophene-co-benzothiadiazole (IDT-BT) field-effect transistors (FETs), estimating a switching time of {\tau} ~ 3.3 {\mu}s for the MoS2 FETs. We achieve this by engineering high-quality MoS2 and air-stable IDT-BT inks suitable for inkjet-printing complementary pairs of n-type MoS2 and p-type IDT-BT FETs. We then integrate MoS2 and IDT-BT FETs to realise inkjet-printed complementary logic inverters with a voltage gain |Av| ~ 4 when in resistive load configuration and |Av| ~ 1.36 in complementary configuration. These results represent a key enabling step towards ubiquitous long-term stable, low-cost printed digital 

                                          a. IC     b.  Ic      c. ICs      d. ic.

Q9. arXiv:2011.12403 [cond-mat.mtrl-sci]:[Submitted on 21 Nov 2020]:  

Inherent heating instability of direct microwave sintering process: Sample analysis for porous 3Y-ZrO2. Charles Manière (SDSU), Tony Zahrah, Eugene A. Olevsky (SDSU): ABSTRACT: Direct microwave heating of 3Y-ZrO2 is studied at frequency of 2.45 GHz. Different conditions of input power, sample position and size are tested. For the first time, the experimentally known instability of microwave sintering is explained coupling the effective medium approximation and finite-element method. We show how the material dielectric permittivity imaginary part which increases with temperature and relative density encourages high hot spot phenomena. It is shown that the sample location has a great impact on the temperature distribution and decreasing the sample size promotes temperature homogenization thereby assisting the overall sintering 

                a. phenomena  b. stabilization   c. distribution  d. enhanement.

Q10. arXiv:2011.12459 [cond-mat.str-el]: [Submitted on 25 Nov 2020]: Perovskite as a spin current generator.Makoto Naka, Yukitoshi Motome, Hitoshi Seo.  ABSTRACT: We theoretically show that materials with perovskite-type crystal structures provide a platform for spin current generation, taking advantage of a mechanism requiring neither the spin-orbit coupling nor a ferromagnetic moment, but is based on spin-split band structures in certain kinds of collinear antiferromagnetic states. By investigating a multiband Hubbard model for transition metal compounds by means of the Hartree-Fock approximation and the Boltzmann transport theory, we find that a pure spin current is induced by an electric field applied to a C-type antiferromagnetic metallic phase. The spin current generation originates from a cooperative effect of spatially anisotropic electron transfer integrals owing to the GdFeO3-type lattice distortion, which is ubiquitous in many perovskites, and the collinear spin configuration. We discuss our finding from the symmetry point of view, in comparison with other spin current generator candidates with collinear antiferomagnetism. We also propose several ways to detect the phenomenon in candidate perovskite 

                          a. substances    b. gadgets   c. metalls.  d. materials.

Q11. arXiv:2011.12556 (cond-mat): [Submitted on 25 Nov 2020]: Improving the description of interlayer bonding in TiS2 by Density Functional Theory. Ricci Matteo, Ambrosetti Alberto, Silvestrelli Pier Luigi: ABSTRACT: We investigate energetic and electronic properties of TiS2 , an archetypal van der Waals (vdW) material, from first principles, in the framework of the Density Functional Theory (DFT). In this system a recent experimental study showed a puzzling discrepancy between the distribution of the electron density in the interlayer region obtained by X-ray diffraction data and that computed by DFT, even adopting DFT functionals that should properly include vdW effects. Such a discrepancy could indicate a partial failure of state-of-the-art DFT approaches in describing the weak interlayer interactions of TiS2 and, possibly, of similar systems too. In order to shed light on this issue, we have carried out simulations based on different DFT functionals, basically confirming the mentioned discrepancy with the experimental findings. Subsequently, we have tried to reproduce the experimental interlayer electronic density deformation both by changing the parameters characterizing the rVV10 DFT functional (in such a way to artificially modify the strength of the vdW interactions at short or long range), and also by adopting a modified pseudopotential for Sulfur atoms, involving d orbitals. The latter approach turns out to be particularly promising. In fact, using this novel, more flexible pseudopotential, we obtain not only an electronic density deformation closer to the experimental profile, but also a better estimate of the interlayer binding energy. Interestingly, this improvement in the theoretical DFT description is not limited to TiS2 but also applies to other similar layered systems involving S atoms, such as TaS2 , HfS2 , and 

                                        a.  MoS2      b. MoS3    c. MoS4     d. MoS5

Q12. arXiv:2011.12575 (cond-mat): [Submitted on 25 Nov 2020]

Plasmon-driven motion of an individual molecule. Tzu-Chao Hung, et al., ABSTRSACT: We demonstrate that nanocavity plasmons generated a few nanometers away from a molecule can induce molecular motion. For this, we study the well-known rapid shuttling motion of zinc phthalocyanine molecules adsorbed on ultrathin NaCl films by combining scanning tunneling microscopy (STM) and spectroscopy (STS) with STM-induced light emission. Comparing spatially resolved single-molecule luminescence spectra from molecules anchored to a step edge with isolated molecules adsorbed on the free surface, we found that the azimuthal modulation of the Lamb shift is diminished in case of the latter. This is evidence that the rapid shuttling motion is remotely induced by plasmon-exciton coupling. Plasmon-induced molecular motion may open an interesting playground to bridge the nanoscopic and mesoscopic worlds by combining molecular machines with nanoplasmonics to control directed motion of single molecules without the need for local 

                                       a. items   b. probes   c. controls    d. surfaces.

Q13. arXiv:2012.00047 [gr-qc]: [Submitted on 30 Nov 2020]: Wormhole geometries induced by action-dependent Lagrangian theories. Ismael Ayuso, Francisco S. N. Lobo, José P. Mimoso. ABSTRACT: In this work, we explore wormhole geometries in a recently proposed modified gravity theory arising from a non-conservative gravitational theory, tentatively denoted action-dependent Lagrangian theories. The generalized gravitational field equation essentially depends on a background four-vector λμ, that plays the role of a coupling parameter associated with the dependence of the gravitational Lagrangian upon the action, and may generically depend on the spacetime coordinates. Considering wormhole configurations, by using "Buchdahl coordinates", we find that the four-vector is given by λμ=(0,0,λθ,0), and that the spacetime geometry is severely restricted by the condition gttguu=−1, where u is the radial coordinate. We find a plethora of specific asymptotically flat, symmetric and asymmetric, solutions with power law choices for the function λ, by generalizing the Ellis-Bronnikov solutions and the recently proposed black bounce geometries, amongst others. We show that these compact objects possess a far richer geometrical structure than their general relativistic 

                 a. counterparts  b. coordinates. c. geometries. d. structures.

Q14. arXiv:2012.00436 [cond-mat.mtrl-sci]: [Submitted on 1 Dec 2020]: Vibrational Frequency used as Internal Clock Reference to access Molecule -- Metal Charge Transfer Times. Peter Jakob, Sebastian Thussing. ABSTRACT: Dynamical charge transfer processes at molecule-metal interfaces proceed in the few fs time scale that renders them highly relevant to electronic excitations in optoelectronic devices. Yet, knowledge thereof is limited when electronic ground state situations are considered that implicate charge transfer directly at the fermi energy. Here we show that such processes can be accessed by means of vibrational excitations, with non-adiabatic electron-vibron coupling leading to distinct asymmetric line shapes. Thereby the characteristic time scale of this interfacial dynamical charge transfer can be derived by using the vibrational oscillation period as an internal clock 

                     a.   devices    b. situations  c. reference  d. time scale.

Q15. arXiv:2012.00184 [hep-ph]: [Submitted on 1 Dec 2020]: Massive photon propagator in the presence of axionic fluctuations. B. A. S. D. Chrispim, R. C. L. Bruni, M. S. Guimaraes. ABSTRACT: The theory of massive photons in the presence of axions is studied as the effective theory describing the electromagnetic response of semimetals when a particular quartic fermionic pairing perturbation triggers the formation of charged chiral condensates, giving rise to an axionic superconductor. We investigate corrections to the Yukawa-like potential mediated by massive photons due to axion excitations up to one-loop order and compute the modifications of the London penetration 

                               a. width     b. length      c. depth     d. axions.  

Q16. arXiv:2012.00674 [physics.ao-ph]:[Submitted on 27 Nov 2020]: Single-photon distributed free-space spectroscopy. S. Yu, et al., ABSTRACT: Spectroscopy is a well-established nonintrusive tool that has played an important role in identifying substances and quantifying their compositions, from quantum descriptions to chemical and biomedical diagnostics. Challenges exist in accurate measurements in dynamic environments, especially for understanding chemical reactions in arbitrary free-space. We develop a distributed free-space spectroscopy realized by a comb-referenced frequency-scanning single-photon lidar, providing multidimensional (time-range-spectrum) remote sensing. A continuous field experiment over 72 hours is deployed to obtain the spectra of multiple molecules (CO2 and HDO) in free-space over 6 km, with a range resolution of 60 m and a time resolution of 10 min over a spectrum span of 30 GHz. The CO2 and HDO concentrations are retrieved from the spectra acquired. This distributed free-space spectroscopy holds much promise for increasing knowledge of atmospheric environments and chemistry research, especially for complex molecular spectra evolution in any location over large 

                        a. distances   b. free space     c. areas.   d. spectra.

Q17.arXiv:2012.09179 [astro-ph.CO]: [Submitted on 16 Dec 2020]: Wed, 16 Dec 2020 19:00:01 UTC (1,860 KB): Searching for axion-like particle decay in the near-infrared background: an updated analysis. Andrea Caputo, Andrea Vittino, Nicolao Fornengo, Marco Regis, Marco Taoso:ABSTRACT: The extragalactic background light is comprised of the cumulative radiation from all galaxies across the history of the universe. The angular power spectrum of the anisotropies of such a background at near-infrared (IR) frequencies lacks of a complete understanding and shows a robust excess which cannot be easily explained with known sources. Dark matter in the form of axion-like particles (ALPs) with a mass around the electronvolt will decay into two photons with wavelengths in the near-IR band, possibly contributing to the background intensity. We compute the near-IR background angular power spectrum including emissions from galaxies, as well as the contributions from the intra-halo light and ALP decay, and compare it to measurements from the Hubble Space Telescope and Spitzer. We find that the preferred values for the ALP mass and ALP-photon coupling to explain the excess are in tension with star cooling data and observations of dwarf spheroidal g

                   a. galaxies  b. white dwarfs   c. electronvolt    d. Hubble.

Q18. [Submitted on 17 Dec 2020]arXiv:2012.09786 [cond-mat.str-el]: Bulk photovoltaic effect driven by collective excitations in a correlated insulator. Tatsuya Kaneko, Zhiyuan Sun, Yuta Murakami, Denis Golež, Andrew J. Millis. Thu, 17 Dec 2020 17:51:31 UTC (1,210 KB): ABSTRACT: We investigate the bulk photovoltaic effect, which rectifies light into electric current, in a collective quantum state with correlation driven electronic ferroelectricity. We show via explicit real-time dynamical calculations that the effect of the applied electric field on the electronic order parameter leads to a strong enhancement of the bulk photovoltaic effect relative to the values obtained in a conventional insulator. The enhancements include both resonant enhancements at sub-bandgap frequencies, arising from excitation of optically active collective modes, and broad-band enhancements arising from non-resonant deformations of the electronic order. The deformable electronic order parameter produces an injection current contribution to the bulk photovoltaic effect which is entirely absent in a rigid-band approximation to a time-reversal symmetric material. Our findings establish that correlation effects can lead to the bulk photovoltaic effect and demonstrate that the collective behavior of ordered states can yield large nonlinear optical 

                  a. effects   b. parameters  c. responses.  d. approximations.

Q19. [Submitted on 17 Dec 2020]: Children of the Stars: Henri Boffin: Thu, 17 Dec 2020 13:27:56 UTC (1,055 KB): ABSTRACT: Even if it tends to hide more often in the current autumnal season, our host star, the Sun, is the principal source of energy on our planet. It has a luminosity of 3.828e26 Watts, and despite that we receive only 2 parts per billion of this, it allows for the Earth's life to thrive. Moreover, we know that the Sun has been shining in the same way for about 4.6 billion years (the age of the Earth) and will likely still do the same for another 5 billion years or so. The Sun's power engine, as well as the one of all the stars we see in the night sky, has for long been a mystery, but astronomers now have a good understanding of

                                 a. space    b. it.   c. Sun   d.thrive.  

Q20.Schoop Lab: New topological properties found in "old" material of Cobalt disulfide. Schoop Lab discovered the presence of Weyl nodes in bulk CoS2 that allow them to make predictions about its surface properties. The material hosts Weyl-fermions and Fermi-arc surface states within its band structure, which may enable it to serve as a platform for exotic phenomena and places it among materials candidates for use in spintronic devices. The research also settles a long-standing debate, proving that CoS2 is not a true half-metal. A half-metal is any substance that acts as a conductor to electrons of one spin orientation but as an insulator or semiconductor to those of the opposite orientation. Researchers found that bulk CoS2 contains objects called Weyl nodes within its structure that serve as electronic channels that can predict other states at the surface."These electronic states that only exist at the surface have chirality associated with them, and because of that chirality the electrons can also only move in certain directions. Chirality refers to that property that makes an object or system indistinguishable from its mirror image—i.e. not superimposable—and is an important property in many branches of science. Schoop added that the electronic channels are polarized. This magnetism could potentially be used to manipulate the material: scientists can switch the magnetization direction and surface states could then be reconfigured as a response to this applied magnetic 

                      a. strength    b. field     c. potential      d. chirality.

Q21.Prof. Dr. Kotcherlakota Lakshmi Narayana:                                trusciencetrutechnology@blogspot.com ABSTRACT: Narayana-Ramanujam’s Fractional Calculus extended to 1.5 derivative formulation to describe Particles and Fields is an exciting enumeration that vividly projects the Axigra. The Axigra is a combination of Axion plus the Gravitin.   We take mA as the mass of Axigra. Ψ̅   and  Ψ  stand for Dirac Fields and N as a normalization factor and me the mass of Electron. The variations with respect to Ψ̅   and   Ψ are made with Euler-Lagrange equations and, two equations we obtained are of immense use. This paper is presented in four parts. References numbering around five are listed at the end of this paper.The main equation for Axigra employs only two and one-fourth order of differentiation for 

                              a. "A"   b. parts  c. equations  d. use.

Q22. arXiv:2012.10054 [astro-ph.GA][Submitted on 18 Dec 2020]:Fri, 18 Dec 2020 05:29:14 UTC (372 KB) Far-Infrared Line Diagnostics: Improving N/O Abundance Estimates for Dusty Galaxies. Bo Peng, et al., ABSTRACT: The Nitrogen-to-Oxygen (N/O) abundance ratio is an important diagnostic of galaxy evolution since the ratio is closely tied to the growth of metallicity and the star formation history in galaxies. Estimates for the N/O ratio are traditionally accomplished with optical lines that could suffer from extinction and excitation effects, so the N/O ratio is arguably measured better through far-infrared (far-IR) fine-structure lines. Here we show that the [N III]57μm/[O III]52μm line ratio, denoted N3O3, is a physically robust probe of N/O. This parameter is insensitive to gas temperature and only weakly dependent on electron density. Though it has a dependence on the hardness of the ionizing radiation field, we show that it is well corrected by including the [Ne III]15.5μm/[Ne II]12.8μm line ratio. We verify the method, and characterize its intrinsic uncertainties by comparing the results to photoionization models. We then apply our method to a sample of nearby galaxies using new observations obtained with SOFIA/FIFI-LS in combination with available Herschel/PACS data, and the results are compared with optical N/O estimates. We find evidence for a systematic offset between the far-IR and optically derived N/O ratio. We argue this is likely due to that our far-IR method is biased towards younger and denser H II regions, while the optical methods are biased towards older H II regions as well as diffuse ionized gas. This work provides a local template for studies of ISM abundance in the early 

                        a. Galaxy     b. world    c.  methods   d. Universe.

Q23. arXiv:2012.10256 [astro-ph.IM]: Submitted on 18 Dec 2020]:Fri, 18 Dec 2020 14:14:12 UTC (1,210 KB):  Atomic transitions for adaptive optics. Rui Yang, Joschua Hellemeier, Paul Hickson. ABSTRACT: This paper reviews atoms and ions in the upper atmosphere, including the mesospheric metals Na, Fe, Mg+, Si+, Ca+, K and also non-metallic species N, N+, O, H, considering their potential for astronomical adaptive optics. Na and Fe are the best candidates for the creation of polychromatic laser guide stars, with the strongest returns coming from transitions that can be reached by excitation at two wavelengths. Ca+ and Si+ have strong visible-light transitions, but require short wavelengths, beyond the atmospheric cutoff, for excitation from the ground state. Atomic O, N and N+ have strong transitions and high abundances in the mesosphere. The product of column density and cross section for these species can be as high as 105 for O and several hundred for N and N+, making them potential candidates for amplified spontaneous emission. However they require vacuum-ultraviolet wavelengths for 

                         a. emission       b. excitation    c. ground state   d. cutoff.

Q24. arXiv:2012.09865 [hep-ph]: [Submitted on 17 Dec 2020]: Thu, 17 Dec 2020 19:00:00 UTC (1,887 KB): Cosmological and astrophysical probes of dark baryons. David McKeen, Maxim Pospelov, Nirmal Raj. ABSTRACT: We examine the cosmological and astrophysical signatures of a "dark baryon," a neutral fermion that mixes with the neutron. As the mixing is through a higher-dimensional operator at the quark level, production of the dark baryon at high energies is enhanced so that its abundance in the early universe may be significant. Treating its initial abundance as a free parameter, we derive new, powerful limits on the properties of the dark baryon. Primordial nucleosynthesis and the cosmic microwave background provide strong constraints due to the inter-conversion of neutrons to dark baryons through their induced transition dipole, and due to late decays of the dark baryon. Additionally, neutrons in a neutron star could decay slowly to dark baryons, providing a novel source of heat that is constrained by measurements of pulsar  

                     a. rates    b. baryons    c. parameters    d. temperatures.

Q25. arXiv:2012.10103 [gr-qc]: [Submitted on 18 Dec 2020]:Fri, 18 Dec 2020 08:27:51 UTC (17 KB):  A proposal for Heisenberg uncertainty principle and STUR for curved backgrounds: an application to white dwarf, neutron stars and black holes. Stefano Viaggiu. ABSTRACT: After a critical overview of the Generalized Uncertainty Principle (GUP) applied to compact objects, we propose a texture of Heisenberg uncertainty principle in curved spacetimes (CHUP). CHUP allows to write down physically motivated STUR (spacetime uncertainty relations) in a generic background for a non commutative spacetime in terms of tetrad variables. In order to study possible quantum effects for compact astrophysical objects as white dwarf, neutron stars and black holes, an expression for quantum fluctuations is outlined. As a result, contrary to GUP-based claims, we found no evidence for quantum effects concerning equilibrium equation and critical mass Mc for white dwarf and neutron stars. Conversely, our expression for CHUP confirms that general relativistic effects strongly reduce the Oppenheimer-Volkoff Newtonian limit for very compact astrophysical objects as neutron stars. In particular, we found that for a degenerate relativistic Fermi gas, the maximum mass decreases for increasing compactness of the star with a minimum critical mass Mc≃0.59M⊙ at the Buchdahl limit. Finally, we study possible non commutative effects near the event horizon of a 

                   a. black hole b. white dwarf  c. black hole  d. black body. 

Q26. arXiv:2012.13856 [hep-ph]: Submitted on 27 Dec 2020:  Sun, 27 Dec 2020 02:46:30 UTC (30 KB): Fun with colours: the standard model with two colour QCD has radically different long distance physics. Saumen Datta, Sourendu Gupta, Rishi Sharma. ABSTRACT: In our world the standard model of particle physics contains within it the fairly intractable theory called QCD. A toy version with two colours is often studied as a model confining and chiral symmetry breaking field theory. Here we investigate the cascade of changes at various distance scales if we make this change within the standard model. It is possible to limit the changes at the hadronic scale. However, the minor changes that occur actually cascade down to the far infrared, into nuclear and atomic physics, and chemistry. Through this it also possibly affects the evolution of stars and galaxies. We remark on this unexpected sensitivity of the universe to physics at the scale of 

                         a. chemistry      b.quarks     c. galaxies   d. stars.

Q27. arXiv:2012.13946 [hep-ph]: [Submitted on 27 Dec 2020]:Sun, 27 Dec 2020 14:13:07 UTC (109 KB): Broadband Dark Matter Axion Detection using a Cylindrical Capacitor. Yu Gao, Qiaoli Yang. The cosmological axions/axion-like particles can compose a significant part of dark matter, however the uncertainty of their mass is large. Here we propose to search the axions using a cylindrical capacitor, in which the static electric field converts dark matter axions into an oscillating magnetic field. Using a static electric field can greatly reduce the magnetic field background compared to using the B⃗  field that the thermal current in the magnet-coil could be hard to annihilate. A cylindrical setup shields the electric field to the laboratory as well as encompasses the axion induced magnetic field within the capacitor, which results an increased magnetic field strength. The induced oscillating magnetic field then can be picked up by a SQUID-based magnetic-meter. Adding a superconductor ring-coil system into the induced magnetic field region can further boost the sensitivity and maintain the axion dark matter inherent bandwidth. The proposed setup is capable of a wide mass range searches as the signal can also be modulated by adjusting the angle between the electric field and the axion 

                         a. speeds     b. oscillations     c. mass     d. flow.     

Q28.Annals of Physics: Dec. 2020: Entropy functionals and thermodynamics of relativistic geometric flows, stationary quasi-periodic Ricci solitons, and gravity. Iuliana Bubuianu, Sergiu I. Vacaru, Elşen Veli Veliev. Article 168333. Abstract: We investigate gravity models emerging from nonholonomic (subjected to non-integrable constraints) Ricci flows. Considering generalizations of G. Perelman’s entropy functionals, relativistic geometric flow equations, nonholonomic Ricci soliton and equivalent (modified) Einstein equations are derived. There are studied nonholonomic configurations which allow explicit modeling of entropic scenarios for gravity and dark matter (in the E. Verlinde approach and/or other variants). It is shown that using the anholonomic frame deformation method, the systems of nonlinear partial differential equations for geometric flow evolution of nonlinear stationary gravitations systems can be decoupled and integrated in general forms. In this and a series of partner works, we elaborate on stationary models of emergent gravity with quasi-periodic gravitational, matter fields and dark energy/matter structure. Such configurations cannot be described thermodynamically using the concept of Bekenstein-Hawking entropy if area-entropy, holographic or duality relations are not involved. Nevertheless, generalizing G. Perelman statistic thermodynamic approach to models of relativistic Ricci flows and nonholonomic solitons, we can compute respective thermodynamic variables for all types of gravitational and matter field configurations and their geometric evolution. Nonholonomic deformations of the F- and W-entropy considered and relativistic thermodynamic models are studied in more general cases when physically important solutions with quasi-periodic and pattern forming structure are found in modified gravity theories (MGT) and

        a. General Relativity    b. Dark energy   c. stationary models  d. geometric flow.

Q29. arXiv:2101.03083 [astro-ph.HE]: [Submitted on 8 Jan 2021]:Fri, 8 Jan 2021 16:21:35 UTC (2,328 KB):  Radio Emission by Soliton Formation in Hot Streaming Pair Pulsar Plasmas. Jan Benáček, Patricio A. Muñoz, Alina C. Manthei, Jörg Büchner. ABSTRACT: A number of possible pulsar radio emission mechanisms is based on instabilities of the relative streaming and beams in their relativistic electron-positron pair plasma. At saturation the unstable waves can form, in principle, stable solitary waves which could emit the observed intense radio signals. We searched for the proper plasma parameters which would lead to the formation of solitons, investigated their properties and dynamics as well as the resulting oscillations of electrons and positrons possibly leading to radio wave emission. We utilized a one-dimensional version of the relativistic Particle-in-Cell code Acronym, initialized an appropriately parameterized one-dimensional Maxwell-Jüttner velocity space particle distribution and studied the evolution of the resulting streaming instability in the strong pulsar magnetic fields. We found that for plasmas with inverse temperatures ρ≥1.66 or relative electron-positron drift speeds with Lorentz factors γ>40, strong electrostatic solitons form associated with L- and A-mode plasma waves. The parameters of the solitons fulfill the wave emission conditions. For appropriate pulsar parameters the resulting energy densities of L-mode solitons can reach up to 1.1×10^5 erg⋅cm^−3 while those of A-mode solitons reach only up to 1.2×10^4 erg⋅cm^−3. Estimated energy densities of up to 7×1012 erg⋅cm−3 suffice to explain pulsar 

                            a. plasma       b.waves        c. nanoshots      d. emissions.

Q30. arXiv:2101.05132 [physics.atom-ph]: [Submitted on 13 Jan 2021]: Wed, 13 Jan 2021 15:26:35 UTC (3,977 KB): Long-range Rydberg-atom-ion molecules of Rb and Cs. A. Duspayev, X. Han, M.A. Viray, L. Ma, J. Zhao, G. Raithel. :ABSTRACT: We propose a novel type of Rydberg dimer, consisting of a Rydberg-state atom bound to a distant positive ion. The molecule is formed through long-range electric-multipole interaction between the Rydberg atom and the point-like ion. We present potential energy curves (PECs) that are asymptotically connected with Rydberg nP- or nD-states of rubidium or cesium. The PECs exhibit deep, long-range wells which support many vibrational states of Rydberg-atom-ion molecules (RAIMs). We consider photo-association of RAIMs in both the weak and the strong optical-coupling regimes between launch and Rydberg states of the neutral atom. Experimental considerations for the realization of RAIMs are 

                    a. elaborated  b. discussed    c. postulated   d. enumerated.

Q31. arXiv:2101.05192 [hep-ph]: [Submitted on 13 Jan 2021]: Wed, 13 Jan 2021 16:50:42 UTC (4,907 KB): Axion assisted Schwinger effect. Valerie Domcke, Yohei Ema, Kyohei Mukaida. ABSTRACT: We point out an enhancement of the pair production rate of charged fermions in a strong electric field in the presence of time dependent classical axion-like background field, which we call axion assisted Schwinger effect. While the standard Schwinger production rate is proportional to exp(−π(m2+p2T)/E), with m and pT denoting the fermion mass and its momentum transverse to the electric field E, the axion assisted Schwinger effect can be enhanced at large momenta to exp(−πm2/E). The origin of this enhancement is a coupling between the fermion spin and its momentum, induced by the axion velocity. As a non-trivial validation of our result, we show its invariance under field redefinitions associated with a chiral rotation and successfully reproduce the chiral anomaly equation in the presence of helical electric and magnetic fields. We comment on implications of this result for axion cosmology, focussing on axion inflation and axion dark matter 

                       a. effect     b. annhilation   c. result      d. detection.

Q32. arXiv:2101.04679 [hep-ph]: [Submitted on 12 Jan 2021]:Tue, 12 Jan 2021 08:54:45 UTC (79 KB): Positronia' clouds in Universe. I.M. Dremin. ABSTRACT: The intense emission of 511 keV photons from the Galactic center and within terrestrial thunderstorms is attributed to the formation of parapositronia' clouds. Unbound electron-positron pairs and positronia can be created by strong electromagnetic fields produced in interactions of electrically charged objects, in particular, in collisions of heavy nuclei. Kinematics of this process favours abundant creation of the unbound electron-positron pairs with very small masses and the confined parapositronia states which decay directly to two 511 keV quanta. Therefore we propose to consider interactions of electromagnetic fields of colliding heavy ions as a source of low-mass pairs which can transform to 511 keV quanta. Intensity of their creation is enlarged by the factor Z^4 (Z is the electric charge of a heavy ion) compared to protons with Z=1. These processes are especially important at very high energies of nuclear collisions because their cross sections increase proportionally to cube of the logarithm of energy and can even exceed the cross sections of strong interactions which may not increase faster than the squared logarithm of energy. Moreover, production of extremely low-mass e+e−-pairs in ultraperipheral nuclear collisions is strongly enhanced due to the Sommerfeld-Gamow-Sakharov (SGS) factor which accounts for mutual Coulomb attraction of non-relativistic electrons to positrons in case of low pair-masses. This attraction may lead to their annihilation and, therefore, to the increased intensity of 511 keV photons. It is proposed to confront the obtained results to forthcoming experimental data at NICA 

                             a. collider     b. observations     c. findings   d conclusions.

Q33. arXiv:2101.06254 [astro-ph.SR]: Submitted on 15 Jan 2021: Fri, 15 Jan 2021 18:37:52 UTC (8,898 KB): Digital color codes of stars. Jan-Vincent Harre, René Heller. ABSTRACT: Publications in astrophysics are nowadays mainly published and read in digitized formats. Astrophysical publications in both research and in popular outreach often use colorful representations of stars to indicate various stellar types, that is, different spectral types or effective temperatures. Computer generated and computer displayed imagery has become an integral part of stellar astrophysics communication. There is, however, no astrophysically motivated standard color palette for illustrative representations of stars and some stars are actually represented in misleading colors. We use pre-computed PHOENIX and TLUSTY stellar model spectra and convolve them with the three standard color matching functions for human color perception between 360nm and 830nm. The color matching functions represent the three sets of receptors in the eye that respond to red, green, and blue light. For a grid of main sequence stars with effective temperatures between 2300K and 55,000K of different metallicities we present the red-blue-green and hexadecimal color codes that can be used for digitized color representations of stars as if seen from space. We find significant deviations between the color codes of stars computed from stellar spectra and from a black body radiator of the same effective temperature. We illustrate the main sequence in the color wheel and demonstrate that there are no yellow, green, cyan, or purple stars. Red dwarf stars (spectral types M0V - M9V) actually look orange to the human eye. Old white dwarfs such as WD1856+534, host to a newly discovered transiting giant planet candidate, occur pale orange to the human eye, not white. Our freely available software can be used to generate color codes for any input spectrum such as those from planets, galaxies,

                                  a. receptors.  b. stars.   c. quasars etc.    d. white dwarfs.

Q34. arXiv:2101.06281 [astro-ph.EP]: [Submitted on 15 Jan 2021]: Fri, 15 Jan 2021 19:11:02 UTC (5,948 KB): The far reaches of the beta Pictoris debris disk. Markus Janson, Alexis Brandeker, Göran Olofsson, Rene Liseau. ABSTRACT: The nearby young star beta Pictoris hosts a rich and complex planetary system, with at least two giant planets and a nearly edge-on debris disk that contains several dynamical subpopulations of planetesimals. While the inner ranges of the debris disk have been studied extensively, less information is known about the outer, fainter parts of the disk. Here we present an analysis of archival FORS V-band imaging data from 2003-2004, which have previously not been explored scientifically because the halo substructure of the bright stellar point spread function is complex. Through a high-contrast scheme based on angular differential imaging, with a forward-modelling approach to mitigate self-subtraction, we produced the deepest imaging yet for the outer range of the beta Pic disk, and extracted its morphological characteristics. A brightness asymmetry between the two arms of the edge-on disk, which was previously noted in the inner disk, is even more pronounced at larger angular separations, reaching a factor ~10 around 1000 AU. Approaching 2000 AU, the brighter arm is visible at a surface brightness of 27-28 mag/arcsec^2. Much like for the brightness asymmetry, a tilt angle asymmetry exists between the two arms that becomes increasingly extreme at large separations. The outer tilt angle of 7.2 deg can only be explained if the outer disk is farther from an edge-on inclination than the inner disk, or if its dust has a stronger scattering anisotropy, or (most likely) both. The strong asymmetries imply the presence of a highly eccentric kinematic disk component, which may have been caused by a disruptive event thought to have taken place at a closer-in location in the

                        a. disk        b. asymmetry.     c. separations.     d. anisotropy.

Q35. arXiv:2101.06487 [astro-ph.SR]: [Submitted on 16 Jan 2021]: Sat, 16 Jan 2021 17:38:53 UTC (980 KB): Review of the classification and properties of 62 variable stars in Cygnus. P. La Rocca , M. Bonasia, P. Moreo, C. Zamariola, C. Benna, D. Gardiol, G. Pettiti. ABSTRACT: This study aims to assess the properties and classification of 62 variable stars in Cygnus, little studied since their discovery and originally reported in the Information Bulletin on Variable Stars (IBVS) 1302. Using data from previous studies and several astronomical databases, we performed our analysis mainly utilizing a period analysis software and comparing the photometric characteristics of the variables in a Colour-Absolute Magnitude Diagram. For all stars, the variability is confirmed. We discovered new significant results for the period and/or type of 17 variables and highlighted incorrect cross-reference names on astronomical databases for 23 stars. For 3 stars, whose original type was unknown, we propose a new type. We calculated an epoch of a minimum or a maximum for 24 stars; for 3 of them, the epoch has been defined for the first time. This assessment also identifies some cases for which results from the ASAS-SN Catalog of Variable Stars are not consistent with results from Gaia DR2 and/or our 

                                      a. detection.     b. prediction    c. result   d. analysis.

Q36. arXiv:2101.06629 [astro-ph.SR]: [Submitted on 17 Jan 2021]:Sun, 17 Jan 2021 09:30:57 UTC (8,187 KB): Spectroscopic observations of a flare-related coronal jet. Q. M. Zhang, Z. H. Huang, Y. J. Hou, D. Li, Z. J. Ning, Z. Wu. ABSTRACT:  Coronal jets are ubiquitous in active regions (ARs) and coronal holes. In this paper, we study a coronal jet related to a C3.4 circular-ribbon flare in active region 12434 on 2015 October 16. Two minifilaments were located under a 3D fan-spine structure before flare. The flare was generated by the eruption of one filament. The kinetic evolution of the jet was divided into two phases: a slow rise phase at a speed of ∼131 km s^−1 and a fast rise phase at a speed of ∼363 km s^−1 in the plane-of-sky. The slow rise phase may correspond to the impulsive reconnection at the breakout current sheet. The fast rise phase may correspond to magnetic reconnection at the flare current sheet. The transition between the two phases occurred at ∼09:00:40 UT. The blueshifted Doppler velocities of the jet in the Si {\sc iv} 1402.80 Å line range from -34 to -120 km s^−1. The accelerated high-energy electrons are composed of three groups. Those propagating upward along open field generate type \textrm{III} radio bursts, while those propagating downward produce HXR emissions and drive chromospheric condensation observed in the Si {\sc iv} line. The electrons trapped in the rising filament generate a microwave burst lasting for ≤40 s. Bidirectional outflows at the base of jet are manifested by significant line broadenings of the Si {\sc iv} line. The blueshifted Doppler velocities of outflows range from -13 to -101 km s^−1. The redshifted Doppler velocities of outflows range from ∼17 to ∼170 km s^−1. Our multiwavelength observations of the flare-related jet are in favor of the breakout jet model and are important for understanding the acceleration and transport of nonthermal

                            a.Electrons.          b. spins.         c. deuterons      d. protons.

Q37. arXiv:2010.14293 [hep-ex]: [Submitted on 27 Oct 2020]: Tue, 27 Oct 2020 13:51:06 UTC (1,123 KB): ABSTRACT: Search for squarks and gluinos in final states with jets and missing transverse momentum using 139 fb^−1 of √s =13 TeV pp collision data with the ATLAS detector. ATLAS Collaboration. A search for the supersymmetric partners of quarks and gluons (squarks and gluinos) in final states containing jets and missing transverse momentum, but no electrons or muons, is presented. The data used in this search were recorded by the ATLAS experiment in proton-proton collisions at a centre-of-mass energy of √s = 13 TeV during Run 2 of the Large Hadron Collider, corresponding to an integrated luminosity of 139 fb^−1. The results are interpreted in the context of various R-parity-conserving models where squarks and gluinos are produced in pairs or in association and a neutralino is the lightest supersymmetric particle. An exclusion limit at the 95% confidence level on the mass of the gluino is set at 2.30 TeV for a simplified model containing only a gluino and the lightest neutralino, assuming the latter is massless. For a simplified model involving the strong production of mass-degenerate first- and second-generation squarks, squark masses below 1.85 TeV are excluded if the lightest neutralino is massless. These limits extend substantially beyond the region of supersymmetric parameter space excluded previously by similar searches with the ATLAS

                                a. finder   b. detector. c. collider. d. particle.

Q38. arXiv:2101.08504 [physics.app-ph]: [Submitted on 21 Jan 2021]:Thu, 21 Jan 2021 08:44:26 UTC (1,374 KB): Practical development of efficient thermoelectric-photovoltaic hybrid systems based on wide-gap solar cells. Bruno Lorenzi, Paolo Mariani, Andrea Reale, Aldo Di Carlo, Gang Chen, Dario Narducci. ABSTRACT: The decrease of solar cell efficiency with temperature is a known problem for photovoltaics (PV). Temperature sensitivity can lead to a considerable amount of energy losses over the lifetime of solar panels. In this perspective Hybrid Thermoelectric-Photovoltaic (HTEPV) systems, which recover solar cell heat losses to produce an additional power output, can be a suitable option. However only hybridization of wide-gap solar cells is convenient in terms of efficiency gains and deserves investigation to evaluate HTEPV devices effectiveness. In this work we report the modeling and the development of customized bismuth telluride thermoelectric generators, optimized to be hybridized with amorphous silicon (aSi), Gallium Indium Phosphide (GaInP) or Perovskites solar cells. The model results showed in all three cases efficiency gains with a maximum of +3.1% for Perovskites (from 16.4% to 19.5%). These enhancements were then experimentally validated for the case of Perovskites solar cells, for which maximum gains were found to occur at typical operating temperatures of conventional PVs. This experimental evaluation demonstrated in an accurate fashion the real potential of thermoelectric hybridization of solar

                                   a. devices      b. packs    c. vistas     d. cells.

Q39. arXiv:2101.11621 [astro-ph.CO]: [Submitted on 27 Jan 2021]:Wed, 27 Jan 2021 19:00:00 UTC (270 KB): Superheavy scalar dark matter from gravitational particle production in α-attractor models of inflation. Siyang Ling, Andrew J. Long. : ABSTRACT: We study the phenomenon of gravitational particle production as applied to a scalar spectator field in the context of α-attractor inflation. Assuming that the scalar has a minimal coupling to gravity, we calculate the abundance of gravitationally-produced particles as a function of the spectator's mass mχ and the inflaton's α parameter. If the spectator is stable and sufficiently weakly coupled, such that it does not thermalize after reheating, then a population of spin-0 particles is predicted to survive in the universe today, providing a candidate for dark matter. Inhomogeneities in the spatial distribution of dark matter correspond to an isocurvature component, which can be probed by measurements of the cosmic microwave background anisotropies. We calculate the dark matter-photon isocurvature power spectrum and by comparing with upper limits from Planck, we infer constraints on mχ and α. If the scalar spectator makes up all of the dark matter today, then for α=10 and TRH=104 GeV we obtain mχ>1.8×10^13 GeV≈1.2mϕ, where mϕ is the inflaton's

                                 a. particles    b. mass    c. spike     d. dark matter 

Q40. arXiv:2101.11641 [astro-ph.IM]: [Submitted on 27 Jan 2021]: Wed, 27 Jan 2021 19:03:12 UTC (8,087 KB): A classifier for spurious astrometric solutions in Gaia EDR3. Jan Rybizki, Gregory Green, Hans-Walter Rix, Markus Demleitner, Eleonora Zari, Andrzej Udalski, Richard L. Smart, Andy Gould.: ABSTRACT: The Gaia mission is delivering exquisite astrometric data for 1.47 billion sources, which are revolutionizing many fields in astronomy. For a small fraction of these sources the astrometric solutions are poor, and the reported values and uncertainties may not apply. For many analyses it is important to recognize and excise these spurious results, commonly done by means of quality flags in the Gaia catalog. Here we devise and apply a path to separating 'good' from 'bad' astrometric solutions that is an order-of-magnitude cleaner than any single flag: we achieve a purity of 99.7% and a completeness of 97.6% as validated on our test data. We devise an extensive sample of manifestly bad astrometric solutions: sources whose inferred parallax is 'negative' at >= 4.5 sigma; and a corresponding sample of presumably good solutions: the sources in HEALPix patches of the sky that do not contain extremely negative parallaxes. We then train a neural net that uses 14 pertinent Gaia catalog entries to discriminate these two samples, captured in a single 'astrometric fidelity' parameter. An extensive and diverse set of verification tests show that our approach to assessing astrometric fidelity works very cleanly also in the regime where no negative parallaxes are involved; its main limitations are in the very low S/N regime. Our astrometric fidelities for all EDR3 can be queried via the Virtual Observatory. In the spirit of open science, we make our code and training/validation data public, so that our results can be easily 

                   a. extracted    b.  visualised. c. reproduced     d. obtained.

Q41. arXiv:2101.11735 [astro-ph.CO]: Submitted on 27 Jan 2021]: Wed, 27 Jan 2021 22:50:33 UTC (903 KB): Wave Dark Matter. Lam Hui (Columbia University). :ABSTRACT: We review the physics and phenomenology of wave dark matter: a bosonic dark matter candidate lighter than about 30 eV. Such particles have a de Broglie wavelength exceeding the average inter-particle separation in a galaxy like the Milky Way, and are well described as classical waves. We outline the particle physics motivations for them, including the QCD axion and ultra-light axion-like-particles such as fuzzy dark matter. The wave nature of the dark matter implies a rich phenomenology: (1) Wave interference leads to order unity density fluctuations on de Broglie scale. A manifestation is vortices where the density vanishes and around which the velocity circulates. There is one vortex ring per de Broglie volume on average. (2) For sufficiently low masses, soliton condensation occurs at centers of halos. The soliton oscillates and random walks, another manifestation of wave interference. The halo/subhalo abundance is suppressed at small masses, but the precise prediction from numerical wave simulations remains to be determined. (3) For ultra-light ~10−22 eV dark matter, the wave interference substructures can be probed by tidal streams/gravitational lensing. The signal can be distinguished from that due to subhalos by the dependence on stream orbital radius/image separation. (4) Axion detection experiments are sensitive to interference substructures for moderately light masses. The stochastic nature of the waves affects the interpretation of experiments and motivates the measurement of correlation functions. Current constraints and open questions, covering detection experiments and cosmological/galactic/black-hole observations, are 

                       a. discussed    b. enumerated     c. presented      d. manipulated.

Q42. arXiv:2101.11880 [astro-ph.HE]: [Submitted on 28 Jan 2021]: Thu, 28 Jan 2021 09:18:56 UTC (1,138 KB). Cosmic Gamma Ray Bursts. A. Janiuk, B. James, K. Sapountzis. :ABSTRACT: Gamma ray bursts (GRBs) are astronomical phenomena detected at highest energies. The gamma ray photons carry energies on the order of mega-electronovolts and arrive to us from the point-like sources that are uniformly distributed on the sky. A typical burst has a form of a pulse that lasts for about a minute. As the Earth atmosphere is not transparent to the very high energy radiation, the bursts are detected by means of the telescopes onboard satellites that are placed on the orbit. The total energetics of GRB events, which is given by the integrated energy flux by the detector unit area, implies that we are witnessing very powerful explosions, where an enormously great power is released within a short time. There is only one way to obtain such huge energies in cosmos: the disruption of a 

                               a.  burst     b. gamma ray      c.  orbit    d. star.  

Q43. arXiv:2102.07408 [astro-ph.CO]: [Submitted on 15 Feb 2021]:Mon, 15 Feb 2021 09:19:21 UTC (240 KB): Standard Model Baryon Number Violation Seeded by Black Holes. V. De Luca, G. Franciolini, A. Kehagias, A. Riotto. ABSTRACT: We show that black holes with a Schwarzschild radius of the order of the electroweak scale may act as seeds for the baryon number violation within the Standard model via sphaleron transitions. The corresponding rate is faster than the one in the pure vacuum and baryon number violation around black holes can take place during the evolution of the universe after the electroweak phase transition. We show however that this does not pose any threat for a pre-existing baryon asymmetry in the 

                          a. standard model       b.   universe      c. galaxy      d. baryons

Q44. arXiv:2102.07677 [astro-ph.EP]: [Submitted on 15 Feb 2021]:Mon, 15 Feb 2021 17:10:09 UTC (2,762 KB): A backward-spinning star with two coplanar planets. Maria Hjorth, et al. : ABSTRACT: It is widely assumed that a star and its protoplanetary disk are initially aligned, with the stellar equator parallel to the disk plane. When observations reveal a misalignment between stellar rotation and the orbital motion of a planet, the usual interpretation is that the initial alignment was upset by gravitational perturbations that took place after planet formation. Most of the previously known misalignments involve isolated hot Jupiters, for which planet-planet scattering or secular effects from a wider-orbiting planet are the leading explanations. In theory, star/disk misalignments can result from turbulence during star formation or the gravitational torque of a wide-orbiting companion star, but no definite examples of this scenario are known. An ideal example would combine a coplanar system of multiple planets -- ruling out planet-planet scattering or other disruptive post-formation events -- with a backward-rotating star, a condition that is easier to obtain from a primordial misalignment than from post-formation perturbations. There are two previously known examples of a misaligned star in a coplanar multi-planet system, but in neither case has a suitable companion star been identified, nor is the stellar rotation known to be retrograde. Here, we show that the star K2-290 A is tilted by 124±6 degrees compared to the orbits of both of its known planets, and has a wide-orbiting stellar companion that is capable of having tilted the protoplanetary disk. The system provides the clearest demonstration that stars and protoplanetary disks can become grossly misaligned due to the gravitational torque from a neighbouring 

                                a. star       b. black hole    c. galazxy      d. disk.    

Q45. arXiv:2102.07721 [astro-ph.HE][Submitted on 15 Feb 2021]:Mon, 15 Feb 2021 18:15:58 UTC (4,513 KB): Fully general-relativistic simulations of isolated and binary strange quark stars. Zhenyu Zhu, Luciano Rezzolla. ABSTRACT: The hypothesis that strange quark matter is the true ground state of matter has been investigated for almost four decades, but only a few works have explored the dynamics of binary systems of quark stars. This is partly due to the numerical challenges that need to be faced when modelling the large discontinuities at the surface of these stars. We here present a novel technique in which the EOS of a quark star is suitably rescaled to produce a smooth change of the specific enthalpy across a very thin crust. The introduction of the crust has been carefully tested by considering the oscillation properties of isolated quark stars, showing that the response of the simulated quark stars matches accurately the perturbative predictions. Using this technique, we have carried out the first fully general-relativistic simulations of the merger of quark-star binaries finding several important differences between quark-star binaries and hadronic-star binaries with the same mass and comparable tidal deformability. In particular, we find that dynamical mass loss is significantly suppressed in quark-star binaries. In addition, quark-star binaries have merger and post-merger frequencies that obey the same quasi-universal relations derived from hadron stars if expressed in terms of the tidal deformability, but not when expressed in terms of the average stellar compactness. Hence, it may be difficult to distinguish the two classes of stars if no information on the stellar radius is available. Finally, differences are found in the distributions in velocity and entropy of the ejected matter, for which quark-stars have much smaller tails. Whether these differences in the ejected matter will leave an imprint in the electromagnetic counterpart and nucleosynthetic yields remains unclear, calling for the construction of an accurate model for the evaporation of the ejected quarks into 

                                a.    fermions     b. quarks   c. stars     d. nucleons. 

Q46. arXiv:2102.08456 [astro-ph.HE]:[Submitted on 16 Feb 2021]: Possibility of measurement of cosmic ray electron spectrum up to 100 TeV with two-layer water Cherenkov detector array. A.Neronov, D.Semikoz. :ABSTRACT: Measurements of cosmic ray electron+positron spectrum above 10 TeV with ground-based experiments is challenging because of the difficulty of rejection of hadronic extensive air shower background. We study the efficiency of rejection of the hadronic background with water Cherenkov detector array supplemented by muon detection layer. We show that addition of a continuous muon detection layer to the experimental setup allows to achieve a ~ 1e-5 rejection factor for hadronic background at 10 TeV and enables measurement of electron spectrum in 10-100 TeV energy range. We show that measurements of electron spectrum in this energy range do not require a high-altitude experiment and can be done with a sea-level

                                          a. array      b.  detector     c. finder     d. range.

Q47. arXiv:2102.08764 [hep-ex][Submitted on 17 Feb 2021]:  Wed, 17 Feb 2021 13:56:58 UTC (933 KB): Axion search with quantum nondemolition detection of magnons. Tomonori Ikeda, et al.: ABSTRACT: The axion provides a solution for the strong CP problem and is one of the leading candidates for dark matter. This paper proposes an axion detection scheme based on quantum nondemolition detection of magnon, i.e., quanta of collective spin excitations in solid, which is expected to be excited by the axion-electron interaction predicted by the Dine-Fischer-Srednicki-Zhitnitsky (DFSZ) model. The prototype detector is composed of a ferromagnetic sphere as an electronic spin target and a superconducting qubit. Both of these are embedded inside a microwave cavity, which leads to a coherent effective interaction between the uniform magnetostatic mode in the ferromagnetic crystal and the qubit. An upper limit for the coupling constant between an axion and an electron is obtained as gaee<1.6×10^−7 at the 95\% confidence level for the axion mass of 33.117μeV<ma

                          a. <33.130μeV    b.  <32.13μeV   c.  <30.12μeV     d. <21.32μeV 

Q48. arXiv:2102.09078 [astro-ph.CO]:[Submitted on 18 Feb 2021]:Thu, 18 Feb 2021 00:07:55 UTC (108 KB): Estimation of the Mass of Dark Matter Using the Observed Mass Profiles of Late-Type alaxies. Ahmad Borzou. :ABSTRACT: We analyze observations of the mass profiles of 175 late-type galaxies in the Spitzer Photometry \& Accurate Rotation Curves (SPARC) database to construct the temperature profile of their dark matter (DM) halos by assuming that (1) DM in the halos obeys either the Fermi-Dirac or the Maxwell-Boltzmann distribution, and (2) the halos are in the virial state. We derive the dispersion velocity of DM at the center of the halos and show that its correlation with the halo's total mass is the same as the one estimated in N-body simulations. The correlation is also the same as the observed relation between the two variables for visible matter in galaxies. Taking the latter agreement as a validation of our analysis, we derive the mass to the temperature of DM at the edge of the halos and show that it is galaxy independent and is equal to m/TR≃10^10 in natural units. Since the analyzed galaxies are far away in the sky, we conclude that DM is a thermal relic, and TR in the above ratio can be expressed in terms of the temperature of the cosmic microwave background (CMB) at the time of DM decoupling. This result is used to study possible cosmological scenarios. We show that observations are at odds with (1) non-thermal DM, (2) hot DM, and (3) collision-less cold DM. Our findings are in favor of a warm DM with a mass of ~

                                          a. 0.5 MeV   b.   7.6MeV    c. 1MeV   d. 20MeV.

Q49. arXiv:2102.09203 [astro-ph.CO]: [Submitted on 18 Feb 2021]: Thu, 18 Feb 2021 07:56:13 UTC (28 KB): A new take on the inflationary quintessence. Zurab Kepuladze, Michael Maziashvili. :ABSTRACT: The quintessence field coupled to the cosmic neutrino background (CNB) has been widely discussed as an alternative mechanism to address the coincidence problem. As it is well known, it is possible to extend such models to obtain quintessential inflation, that is, to incorporate inflationary stage as well. Taking an alternative route, one can start from the well established inflationary models and obtain successful quintessence models at the expense of coupling with the CNB. To Follow this route, we use a slightly reformulated model addressed in PRD95, 123521 (2017). This particular model assumes Z2 symmetry for both scalar field potential and coupling term, which then breaks down in course of the cosmological evolution. For our discussion, however, the Z2 symmetry of the potential is not mandatory the model to work. The conventional mechanism of particle production by the oscillating inflaton field (and their subsequent thermalization) remains operative. It is plain to see that the proposed construction can be easily applied for many successful models of inflation to incorporate dark energy at the expense of coupling with the CNB. We address the issue of neutrino nuggets from the quantum field theory point of view. Namely, these nuggets are considered as bound states caused basically by the Yukawa force, which arises in the framework of linear perturbation theory due to exchange of virtual quanta of quintessence field between the 

                          a. fermions      b. neutrinos    c. scalar fields    d. CNB.

Q50. arXiv:2102.09574 [astro-ph.HE]: [Submitted on 18 Feb 2021]: Thu, 18 Feb 2021 19:00:03 UTC (707 KB): Accretion onto a small black hole at the center of a neutron star. Chloe B. Richards, Thomas W. Baumgarte, Stuart L. Shapiro. :ABSTRACTS: We revisit the system consisting of a neutron star that harbors a small, possibly primordial, black hole at its center, focusing on a nonspinning black hole embedded in a nonrotating neutron star. Extending earlier treatments, we provide an analytical treatment describing the rate of secular accretion of the neutron star matter onto the black hole, adopting the relativistic Bondi accretion formalism for stiff equations of state that we presented elsewhere. We use these accretion rates to sketch the evolution of the system analytically until the neutron star is completely consumed. We also perform numerical simulations in full general relativity for black holes with masses up to nine orders of magnitude smaller than the neutron star mass, including a simulation of the entire evolution through collapse for the largest black hole mass. We construct relativistic initial data for these simulations by generalizing the black hole puncture method to allow for the presence of matter, and evolve these data with a code that is optimally designed to resolve the vastly different length scales present in this problem. We compare our analytic and numerical results, and provide expressions for the lifetime of neutron stars harboring such endoparasitic 

                         a.  white holes  b. matter   c. evolution     d. black holes.

Q51. arXiv:2102.09839 [astro-ph.SR]: [Submitted on 19 Feb 2021]: Fri, 19 Feb 2021 10:17:03 UTC (1,075 KB): A photometric study of two neglected eclipsing binaries. V. Kudak, M. Fedurco, V. Perig, Š. Parimucha. : ABSTRACT: We present the first BVR photometry, period variation, and photometric light-curve analysis of two poorly studied eclipsing binaries V1321 Cyg and CR Tau. Observations were carried out from November 2017 to January 2020 at the observatory of Uzhhorod National University. Period variations were studied using all available early published as well as our minima times. We have used newly developed ELISa code for the light curve analysis and determination of photometric parameters of both systems. We found that V1321 Cyg is a close detached eclipsing system with a low photometric mass ratio of q=0.28 which suggests that the binary is a post mass transfer system. No significant period changes in this system are detected. CR Tau is, on the other hand, a semi-detached system where the secondary component almost fills its Roche lobe. We detected a long-term period increase at a rate of 1.49×10^−7d/y, which support mass transfer from lower mass secondary component to the more massive 

                            a. secondary   b. primary     c. eclipse        d. binary

Q52. arXiv:2102.10023 [astro-ph.GA][Submitted on 19 Feb 2021]: Fri, 19 Feb 2021 16:43:33 UTC (1,418 KB): Infrared action spectroscopy of doubly charged PAHs and their contribution to the aromatic infrared bands. Shreyak Banhatti, Julianna Palotás, Pavol Jusko, Britta Redlich, Jos Oomens, Stephan Schlemmer, Sandra Brünken. : ABSTRACT: The so-called aromatic infrared bands are attributed to emission of polycyclic aromatic hydrocarbons. The observed variations toward different regions in space are believed to be caused by contributions of different classes of PAH molecules, i.e. with respect to their size, structure, and charge state. Laboratory spectra of members of these classes are needed to compare them to observations and to benchmark quantum-chemically computed spectra of these species. In this paper we present the experimental infrared spectra of three different PAH dications, naphthalene2+, anthracene2+, and phenanthrene2+, in the vibrational fingerprint region 500-1700~cm^−1. The dications were produced by electron impact ionization of the vapors with 70 eV electrons, and they remained stable against dissociation and Coulomb explosion. The vibrational spectra were obtained by IR predissociation of the PAH2+ complexed with neon in a 22-pole cryogenic ion trap setup coupled to a free-electron infrared laser at the Free-Electron Lasers for Infrared eXperiments (FELIX) Laboratory. We performed anharmonic density-functional theory calculations for both singly and doubly charged states of the three molecules. The experimental band positions showed excellent agreement with the calculated band positions of the singlet electronic ground state for all three doubly charged species, indicating its higher stability over the triplet state. The presence of several strong combination bands and additional weaker features in the recorded spectra, especially in the 10-15~μm region of the mid-IR spectrum, required anharmonic calculations to understand their effects on the total integrated intensity for the different charge states. These measurements, in tandem with theoretical calculations, will help in the identification of this specific class of doubly-charged PAHs as carriers of 

                              a.  AIBs       b. FELIX      c.   spectra      d.  triplet state.

Q53. arXiv:2102.09565 [cond-mat.mes-hall]: Submitted on 18 Feb 2021]: Thu, 18 Feb 2021 19:00:00 UTC (6,064 KB): Fully tunable exciton-polaritons emerging from WS2 monolayer excitons in an optical lattice at room temperature. Lukas Lackner, et al. : ABSTRACT: Engineering non-linear hybrid light-matter states in tailored optical lattices is a central research strategy for the simulation of complex Hamiltonians. Excitons in atomically thin crystals are an ideal active medium for such purposes, since they couple strongly with light and bear the potential to harness giant non-linearities and interactions while presenting a simple sample-processing and room temperature operability. We demonstrate lattice polaritons, based on an open, high-quality optical cavity, with an imprinted photonic lattice strongly coupled to excitons in a WS2 monolayer. We experimentally observe the emergence of the canonical band-structure of particles in a one-dimensional lattice at room temperature, and demonstrate frequency reconfigurability over a spectral window exceeding 12 meV, as well as the systematic variation of the nearest neighbour coupling, reflected by a tuneability in the bandwidth of the p-band polaritons by 7 meV. The technology presented in this work is a critical demonstration towards reconfigurable photonic emulators operated with non-linear photonic fluids, offering a simple experimental implementation and working at ambient 

                         a.  axions     b. purposes     c. conditions       d. variations.

 Q54. arXiv:2102.12483 [hep-ph]: [Submitted on 24 Feb 2021]:Wed, 24 Feb 2021 19:00:00 UTC (7,966 KB): Solar reflection of light dark matter with heavy mediators. Timon Emken. :ABSTRACT: The direct detection of sub-GeV dark matter particles is hampered by their low energy deposits. If the maximum deposit allowed by kinematics falls below the energy threshold of a direct detection experiment, it is unable to detect these light particles. Mechanisms that boost particles from the galactic halo can therefore extend the sensitivity of terrestrial direct dark matter searches to lower masses. Sub-GeV and sub-MeV dark matter particles can be efficiently accelerated by colliding with thermal nuclei and electrons of the solar plasma respectively. This process is called `solar reflection'. In this paper, we present a comprehensive study of solar reflection via electron and/or nuclear scatterings using Monte Carlo simulations of dark matter trajectories through the Sun. We study the properties of the boosted dark matter particles, obtain exclusion limits based on various experiments probing both electron and nuclear recoils, and derive projections for future detectors. In addition, we find and quantify a novel, distinct annual modulation signature of a potential solar reflection signal which critically depends on the anisotropies of the boosted dark matter flux ejected from the Sun. Along with this paper, we also publish the corresponding research                   

                    a. software   b. hardware   c. dark matter   d. on detectors.

Q55. arXiv:2102.12690 [physics.optics]: [Submitted on 25 Feb 2021]:Thu, 25 Feb 2021 05:29:10 UTC (7,011 KB): The Control of the Elementary Quantum Systems Radiation Using Metamaterials and Nanometaparticles. Vasily Klimov. :ABSTRACT: The most important direction in the development of fundamental and applied physics is the study of the properties of optical systems at the nanoscale in order to create optical and quantum computers, biosensors, single-photon sources for quantum informatics, devices for DNA sequencing, sensors of various fields, etc. In all these cases, nanoscale light sources - dye molecules, quantum dots (epitaxial or colloidal), color centers in crystals, and nanocontacts in metals - are of key importance. In the nanoenvironment, the characteristics of these elementary quantum systems - pumping rates, radiative and non-radiative decay rates, the local density of states, lifetimes, level shifts - experience changes that can be used intentionally to create nanoscale light sources with desired properties. This review presents an analysis of actual theoretical and experimental works in the field of elementary quantum systems radiation control using plasmonic and dielectric nanostructures, metamaterials, and nanoparticles made from

                a. materials    b. level shifts    c.  quantum systems.   d. metamaterials.

Q56. arXiv:2102.12806 [physics.optics][Submitted on 25 Feb 2021]: Thu, 25 Feb 2021 12:13:02 UTC (388 KB): On the interplay of photons and charge carriers in thin-film solar cells. by Pyry Kivisaari, Mikko Partanen, Toufik Sadi, Jani Oksanen. :ABSTRACT: Thin films are gaining ground in photonics and optoelectronics, promising improvements in their efficiency and functionality as well as decreased material usage as compared to bulk technologies. However, proliferation of thin films would benefit not only from continuous improvements in their fabrication, but also from a unified and accurate theoretical framework of the interplay of photons and charge carriers. In particular, such a framework would need to account quantitatively and self-consistently for photon recycling and interference effects. To this end, here we combine the drift-diffusion formalism of charge carrier dynamics and the fluctuational electrodynamics of photon transport self-consistently using the recently introduced interference-extended radiative transfer equations. The resulting equation system can be solved numerically using standard simulation tools, and as an example, here we apply it to study well-known GaAs thin-film solar cells. In addition to obtaining the expected device characteristics, we analyze the underlying complex photon transport and recombination-generation processes that represent a full solution to the inhomogeneous Maxwell's equations and that are generated directly as a result of solving the self-consistent model. The methodology proposed in this work is general and can be used to obtain accurate physical insight into a wide range of planar optoelectronic devices, of which the thin-film single-junction solar cells studied here are only one 

                      a. Illustration   b. example.   c. characteristic  d. transport.

Q57.arXiv:2102.13594 [astro-ph.HE]: [Submitted on 26 Feb 2021]: Fri, 26 Feb 2021 17:00:15 UTC (5,428 KB): Sub-MeV spectroscopy with AstroSat-CZT Imager for Gamma Ray Bursts. Tanmoy Chattopadhyay, et al., :ABSTRACT: Cadmium Zinc Telluride Imager (CZTI) onboard AstroSat has been a prolific Gamma-Ray Burst (GRB) monitor. While the 2-pixel Compton scattered events (100 - 300 keV) are used to extract sensitive spectroscopic information, the inclusion of the low-gain pixels (around 20% of the detector plane) after careful calibration extends the energy range of Compton energy spectra to 600 keV. The new feature also allows single-pixel spectroscopy of the GRBs to the sub-MeV range which is otherwise limited to 150 keV. We also introduced a new noise rejection algorithm in the analysis ('Compton noise'). These new additions not only enhances the spectroscopic sensitivity of CZTI, but the sub-MeV spectroscopy will also allow proper characterization of the GRBs not detected by Fermi. This article describes the methodology of single, Compton event and veto spectroscopy in 100 - 600 keV for the GRBs detected in the first year of operation. CZTI in last five years has detected around 20 bright GRBs. The new methodologies, when applied on the spectral analysis for this large sample of GRBs, has the potential to improve the results significantly and help in better understanding the prompt emission mechanism.

                       a. effect   b. spectroscopy    c. mechanism     d. methodology.

Q58. arXiv:2102.13618 [astro-ph.CO]: [Submitted on 26 Feb 2021]: Fri, 26 Feb 2021 17:38:15 UTC (502 KB): Reconstruction of the neutrino mass as a function of redshift. Christiane S. Lorenz, Lena Funcke, Matthias Löffler, Erminia Calabrese. :ABSTRACT: We reconstruct the neutrino mass as a function of redshift, z, from current cosmological data using both standard binned priors and linear spline priors with variable knots. Using cosmic microwave background temperature, polarization and lensing data, in combination with distance measurements from baryonic acoustic oscillations and supernovae, we find that the neutrino mass is consistent with ∑mν(z)= const. We obtain a larger bound on the neutrino mass at low redshifts coinciding with the onset of dark energy domination, ∑mν(z=0)<1.41 eV (95% CL). This result can be explained either by the well-known degeneracy between ∑mν and ΩΛ at low redshifts, or by models in which neutrino masses are generated very late in the Universe. We convert our results into cosmological limits for models with post-recombination neutrino decay and find ∑mν<0.19 eV (95% CL), which is below the sensitivity of the KATRIN experiment. Thus, a neutrino mass discovery by KATRIN would hint towards models predicting both post-recombination neutrino mass generation and subsequent relic neutrino 

                     a.disintegration   b. annihilation      c. scatter   d. oscillation.

Q59. arXiv:2102.13171 [physics.app-ph]: [Submitted on 25 Feb 2021]: Thu, 25 Feb 2021 20:54:48 UTC (2,469 KB): Nuclear spin temperature reversal via continuous radio-frequency driving. Pablo R. Zangara, et al., :ABSTRACT: Optical spin pumping of color centers in diamond is presently attracting broad interest as a platform for dynamic nuclear polarization at room temperature, but the mechanisms involved in the generation and transport of polarization within the host crystal are still partly understood. Here we investigate the impact of continuous radio-frequency (RF) excitation on the generation of nuclear magnetization produced by optical illumination. In the presence of RF excitation far removed from the nuclear Larmor frequency, we witness a magnetic-field-dependent sign reversal of the measured nuclear spin signal when the drive is sufficiently strong, a counter-intuitive finding that immediately points to non-trivial spin dynamics. With the help of analytical and numerical modeling, we show our observations indicate a modified form of 'solid effect', down-converted from the microwave to the radio-frequency range through the driving of hybrid transitions involving one (or more) nuclei and two (or more) electron spins. Our results open intriguing opportunities for the manipulation of many-electron spin systems by exploiting hyperfine couplings as a means to access otherwise forbidden intra-band

                              a. coupling   b. access   c.observation     d. transitions. 

Q60. arXiv:2102.13316 [physics.optics]: [Submitted on 26 Feb 2021]:Fri, 26 Feb 2021 06:10:22 UTC (2,165 KB): Optoelectronic characteristics and application of black phosphorus and its analogs. Ying-Ying Li, Bo Gao, Ying Han, Bing-Kun Chen, Jia-Yu Huo. :ABSTRACT: The tunable bandgap from 0.3 eV to 2 eV of black phosphorus (BP) makes it to fill the gap in graphene. When studying the properties of BP more comprehensive, scientists have discovered that many two-dimensional materials, such as tellurene, antimonene, bismuthene, indium selenide and tin sulfide, have similar structures and properties to black phosphorus thus called black phosphorus analogs. In this review, we briefly introduce preparation methods of black phosphorus and its analogs, with emphasis on the method of mechanical exfoliation (ME), liquid phase exfoliation (LPE) and chemical vapor deposition (CVD). And their characterization and properties according to their classification of single-element materials and multi-element materials are described. We focus on the performance of passively mode-locked fiber lasers using BP and its analogs as saturable absorbers (SA) and demonstrated this part through classification of working wavelength. Finally, we introduce the application of BP and its analogs, and discuss their future research 

                      a. prospects     b.  endventures     c. thoughts     d. reviews.

Q61.  arXiv:2102.13112 [hep-ph]: [Submitted on 25 Feb 2021]:Thu, 25 Feb 2021 19:00:00 UTC (89 KB): istent treatment of axions in the weak chiral Lagrangian. Martin Bauer  Matthias Neubert,  Sophie Renner, Marvin Schnubel, Andrea Thamm :ABSTRACT: We present a consistent implementation of weak decays involving an axion or axion-like particle in the context of an effective chiral Lagrangian. We argue that previous treatments of such processes have used an incorrect representation of the flavor-changing quark currents in the chiral theory. As an application, we derive model-independent results for the decays K−→π−a and π−→e−ν¯ea at leading order in the chiral expansion and for arbitrary axion couplings and mass. In particular, we find that the K−→π−a branching ratio is almost 40 times larger than previously 

                          a. thought    b.   deciphered    c. estimated      d. decoded.

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ANSWERS for TRUWIZ122a. Dated September 09, 2021.

Q1.a,Q2.b,Q3.aQ4.d,Q5.b,Q6.c,Q7.a,Q8.c,Q9.b,Q10.d,Q11.a,Q12.b,Q13.a,Q14.c, Q15.b,Q16.c,Q17.a, Q18.c,Q19.b, Q20.b,Q21.a, Q22.d, Q23.b, Q24.d,Q25.c,Q26.b,Q27.d, Q28.a,Q29.c,Q30.b,Q31.d,Q32.a,Q33.c,Q34.a,Q35.d,Q36.a,Q37.b,Q38.d,Q39.b, Q40.c,Q41.a,Q42.d,Q43.b,Q44.a,Q45.d,Q46.b,Q47.a,Q48.c,Q49.b,Q50.d,Q51.b,Q52.a, Q53.c,Q54.a,Q55.d,Q56.b,Q57.c,Q58b,Q59.d, Q60.a,Q61.c.

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Contd. with TRUWIZ122b.