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In this work, we develop the Raychaudhuri equation in $f(\bar{R},\bar{T})$ gravity in the setting of a non-canonical theory, namely K-essence theory. We solve the modified Raychaudhuri equation for the additive form of $f(\bar{R},\bar{T})$, which is $f_{1}(\bar{R})+f_{2}(\bar{T})$. For this solution, we employ two different scale factors to give two types of $f(\bar{R},\bar{T})$ solutions. The ongoing debate between Fisher et. al. and Harko et. al. in 2020 regarding the additive form of $f(\bar{R},\bar{T})$ may provide a resolution within the modified $f(\bar{R},\bar{T})$ gravity theory. By conducting a viability test and analyzing energy conditions, we have determined that in the first scenario, the null energy condition (NEC) is violated between two regions where the NEC is satisfied. Additionally, we have observed that this violation of the NEC exhibits a symmetric property during the phase transition. These observations indicate that bouncing events may occur as a result of the symmetrical violation of the NEC during the expansion of the universe. Moreover, this model indicates that resonant-type quantum tunneling may take place during the period when the NEC is violated. The findings of NEC violation through the power law of scale factor may have empirical relevance in contemporary observations. In the second scenario, our model indicates that the strong energy condition is violated, but the NEC and weak energy conditions are satisfied. The effective energy density decreases and is positive, while the effective pressure and equation of state parameters are negative. This suggests that the universe is expanding with acceleration and is dominated by dark energy., Comment: 29 pages, 37 figures, 4 tables, Comments invited

The search for the simplest amino acid, glycine (NH$_{2}$CH$_{2}$COOH), in the interstellar medium (ISM), has become a never-ending story for astrochemistry and astrophysics researchers because that molecule plays a possible connection between the Universe and the origin of life. In the last forty years, all searches for NH$_{2}$CH$_{2}$COOH in the ISM at millimeter and submillimeter wavelengths have failed. Since the detection of NH$_{2}$CH$_{2}$COOH in the ISM was extremely difficult, we aimed to search for the possible precursors of NH$_{2}$CH$_{2}$COOH. Earlier, many laboratory experiments have suggested that methylamine (CH$_{3}$NH$_{2}$) plays an important role in the ISM as a possible precursor of NH$_{2}$CH$_{2}$COOH. After spectral analysis using the local thermodynamic equilibrium (LTE) model, we identified the rotational emission lines of CH$_{3}$NH$_{2}$ towards the hot molecular core G358.93$-$0.03 MM1 using the Atacama Large Millimeter/Submillimeter Array (ALMA). The column density of CH$_{3}$NH$_{2}$ towards the G358.93$-$0.03 MM1 was estimated to be (1.10$\pm$0.31)$\times$10$^{17}$ cm$^{-2}$ with an excitation temperature of 180.8$\pm$25.5 K. The fractional abundance of CH$_{3}$NH$_{2}$ with respect to H$_{2}$ towards the G358.93$-$0.03 MM1 was (8.80$\pm$2.60)$\times$10$^{-8}$. The column density ratio of CH$_{3}$NH$_{2}$ and NH$_{2}$CN towards G358.93$-$0.03 MM1 was (1.86$\pm$0.95)$\times$10$^{2}$. The estimated fractional abundance of CH$_{3}$NH$_{2}$ towards the G358.93$-$0.03 MM1 agrees fairly well with the previous three-phase warm-up chemical modelling abundance of CH$_{3}$NH$_{2}$. We also discussed the possible formation mechanism of CH$_{3}$NH$_{2}$, and we find that CH$_{3}$NH$_{2}$ is most probably formed via the reactions of radical CH$_{3}$ and radical NH$_{2}$ on the grain surface of G358.93$-$0.03 MM1., Comment: Published in New Astronomy

The use of semiconductor nanocrystals in scalable quantum technologies requires characterization of the exciton coherence dynamics in an \emph{ensemble} of electronically isolated crystals in which system-bath interactions are nevertheless strong. In this communication, we identify signatures of Fano-like interference between excitons and photocarriers in the coherent two-dimensional photoluminescence excitation spectral lineshapes of mixed lead-halide perovskite nanocrystals in dilute solution. Specifically, by tuning the femtosecond-pulse spectrum, we show such interference in an intermediate coupling regime, which is evident in the coherent lineshape when simultaneously exciting the exciton and the free-carrier band at higher energy. We conclude that this interference is an intrinsic effect that will be consequential in the quantum dynamics of the system and will thus dictate decoherence dynamics, with consequences in their application in quantum technologies., Comment: Submitted to The Journal of Chemical Physics. The Supplemental Materials document SI.pdf can be downloaded from the Tex Source link

Rhenium-based superconductors have recently attracted significant interest due to their unconventional superconducting properties. In this work, we report the synthesis and properties of new superconducting Re$_{7}$X$_{3}$ (X = Nb, Ta, Ti, Zr, Hf) binary alloys which maintain a fixed composition of rhenium while crystallizing in centrosymmetric to non-centrosymmetric crystal structures, depending on the elements of the X site. Comprehensive structural and superconducting properties were investigated using powder x-ray diffraction, AC transport, magnetization, and specific heat measurements, and on the basis of these measurements, the superconducting phase diagram was constructed. The results suggest a complex interplay of crystal structure and the Re/X ratio, which governs the strength of spin-orbital coupling and controls the unconventional superconducting behavior in Re-based superconductors., Comment: 8 pages, 9 figure

We define the $Q$-factor in the percolation problem as the quotient of the size of the largest cluster and the average size of all clusters. As the occupation probability $p$ is increased, the $Q$-factor for the system size $L$ grows systematically to its maximum value $Q_{max}(L)$ at a specific value $p_{max}(L)$ and then gradually decays. Our numerical study of site percolation problems on the square, triangular and the simple cubic lattices exhibits that the asymptotic values of $p_{max}$ though close, are distinctly different from the corresponding percolation thresholds of these lattices. We have also shown using the scaling analysis that at $p_{max}$ the value of $Q_{max}(L)$ diverges as $L^d$ ($d$ denoting the dimension of the lattice) as the system size approaches to their asymptotic limit. We have further extended this idea to the non-equilibrium systems such as the sandpile model of self-organized criticality. Here, the $Q(\rho,L)$-factor is the quotient of the size of the largest avalanche and the cumulative average of the sizes of all the avalanches; $\rho$ being the drop density of the driving mechanism. This study has been prompted by some observations in Sociophysics., Comment: 9 pages, 13 figures

Understanding the nature of the photoexcitation and ultrafast charge dynamics pathways in organic halide perovskite nanocubes and their aggregation into superlattices is key for the potential applications as tunable light emitters, photon harvesting materials and light-amplification systems. In this work, we apply two-dimensional coherent electronic spectroscopy (2DES) to track in real time the formation of near-infrared optical excitons and their ultrafast relaxation in CH(NH2)2PbI3 nanocube superlattices. Our results unveil that the coherent ultrafast dynamics is limited by the combination of the inherent short exciton decay time ~40 fs and the dephasing due to the coupling with selective optical phonon modes at higher temperatures. On the picosecond timescale, we observe the progressive formation of long-lived localized trap states. The analysis of the temperature dependence of the excitonic intrinsic linewidth, as extracted by the anti-diagonal components of the 2D spectra, unveils a dramatic change of the excitonic coherence time across the cubic to tetragonal structural transition. Our results offer a new way to control and enhance the ultrafast coherent dynamics of photocarrier generation in hybrid halide perovskite synthetic solids.

In [arXiv:1906.10100], the authors argued that the Newman-Janis algorithm on the space of classical solutions in general relativity and electromagnetism could be used in the space of scattering amplitudes to map an amplitude with external scalar states to an amplitude associated to the scattering of "infinite spin particles". The minimal coupling of these particles to the gravitational or Maxwell field is equivalent to the classical coupling of the Kerr black hole with linearized gravity or the so-called $\sqrt{\text{Kerr}}$ charged state with the electromagnetic field. The action of the Newman-Janis mapping on scattering amplitudes was then used to compute the linear impulse at first post-Minkowskian (1PM) order, via the Kosower, Maybee, O'Connell (KMOC) formalism. In this paper, we continue with the idea of using the Newman-Janis mapping on the space of scalar QED amplitudes to compute classical observables such as the radiative gauge field and the angular impulse. We show that for tree-level amplitudes, the Newman-Janis action can be reinterpreted as a dressing of the photon propagator. This turns out to be an efficient way to compute these classical observables. Along the way, we highlight a subtlety that arises in proving the conservation of angular momentum for scalar -$\sqrt{\text{Kerr}}$ scattering., Comment: v3: 36 pages, 4 figures, references updated, derivation of orbital angular impulse expression in the KMOC Formalism added (Appendix B), matched with the published version

We will gain unprecedented, high-accuracy insights into the internal structure of the atomic nucleus thanks to lepton-hadron collision studies in the coming years at the Electron-Ion-Collider (EIC) in the United States. A good control of radiative corrections is necessary for the EIC to be fully exploited and to extract valuable information from various measurements. We present our extension of photoproduction at fixed order in MadGraph5_aMC@NLO, a widely used framework for (next-to-)leading order calculations at the Large Hadron Collider (LHC). It applies to electron-hadron collisions, in which the quasi-real photon comes from an electron as well as to proton-nucleus and nucleus-nucleus collisions., Comment: 2 references added and a couple of sentences modified

We search for MeV gamma-ray emission between 0.75-30 MeV from five galaxy clusters, viz. Coma, VIRGO, SPT-CL J2012-5649, Bullet, and El Gordo, using archival data from the COMPTEL telescope. For this purpose we use three search templates: point source, radial disk and radial Gaussian. We do not detect any signals from Coma, SPT-CL J2012-5649, Bullet and El Gordo clusters with the 95\% c.l. photon energy flux limit $\sim 10^{-10} ~\rm{erg /cm^2/s} $. For VIRGO, we detect a non-zero signal between 0.92 to 1.63 MeV having marginal significance of about $2.5\sigma$, with the observed energy flux $ \sim 10^{-9}~\rm{ergs/cm^2/s}$. However, we do not confirm the previously reported evidence in literature for a gamma-ray line from Coma and VIRGO clusters between 5-7 MeV., Comment: 9 pages, 7 figures. Accepted for publication in JCAP

Communication complexity is a pivotal element in information science, with quantum theory presenting a significant edge over classical approaches. The standard quantification of one-way communication complexity relies on the minimal dimension of the systems that the sender communicates to accomplish the designated task. In this study, we adopt a novel perspective, measuring the complexity of the communication by the distinguishability of the sender's input without constraining the dimension of the communicated systems. This measure becomes especially pertinent when maintaining the confidentiality of the sender's input is essential. After establishing the generic framework, we focus on two important categories of communication complexity tasks - the general version of random access codes and equality problems defined by graphs. We derive lower bounds on the distinguishability of the sender's input as a function of the success metric of these tasks in classical communication. Notably, we show that the ratio between the distinguishability in classical and quantum communication to achieve the same success metric escalates with the complexity of these tasks, reaching arbitrarily large values. Besides, we demonstrate the quantum advantage by employing qubits in solving equality problems associated with odd-cycle graphs. Furthermore, we derive lower bounds on distinguishability for another class of communication tasks, namely, pair-distinguishability tasks, and present several instances of the quantum advantage., Comment: 10 pages. First draft. Comments are welcome

In the interstellar medium (ISM), the complex prebiotic molecule cyanamide (NH$_{2}$CN) plays a key role in producing adenine (C$_{5}$H$_{5}$N$_{5}$), purines (C$_{5}$H$_{4}$N$_{4}$), pyrimidines (C$_{4}$H$_{4}$N$_{2}$), and other biomolecules via a series of reactions. Therefore, studying the emission lines of NH$_{2}$CN is important for understanding the hypothesis of the pre-solar origin of life in the universe. We present the detection of the rotational emission lines of NH$_{2}$CN with vibrational states $v$ = 0 and 1 towards the hot molecular core G31.41+0.31 using the high-resolution twelve-meter array of Atacama Large Millimeter/Submillimeter Array (ALMA) band 3. The estimated column density of NH$_{2}$CN towards G31.41+0.31 using the local thermodynamic equilibrium (LTE) model is (7.21$\pm$0.25)$\times$10$^{15}$ cm$^{-2}$ with an excitation temperature of 250$\pm$25 K. The abundance of NH$_{2}$CN with respect to H$_{2}$ towards G31.41+0.31 is (7.21$\pm$1.46)$\times$10$^{-10}$. The NH$_{2}$CN and NH$_{2}$CHO column density ratio towards G31.41+0.31 is 0.13$\pm$0.02. We compare the estimated abundance of NH$_{2}$CN with that of other hot cores and corinos and observed that the abundance of NH$_{2}$CN towards G31.41+0.31 is nearly similar to that of the hot molecular core G358.93$-$0.03 MM1, the hot corinos IRAS 16293-2422 B, and NGC 1333 IRAS4A2. We compute the two-phase warm-up chemical model of NH$_{2}$CN using the gas-grain chemical code UCLCHEM, and after chemical modelling, we notice that the observed and modelled abundances are nearly similar. After chemical modelling, we conclude that the neutral-neutral reaction between NH$_{2}$ and CN is responsible for the production of NH$_{2}$CN on the grain surface of G31.41+0.31., Comment: Accepted for publication in ACS Earth and Space Chemistry

Reliability issues stemming from device level non-idealities of non-volatile emerging technologies like ferroelectric field-effect transistors (FeFET), especially at scaled dimensions, cause substantial degradation in the accuracy of In-Memory crossbar-based AI systems. In this work, we present a variation-aware design technique to characterize the device level variations and to mitigate their impact on hardware accuracy employing a Bayesian Neural Network (BNN) approach. An effective conductance variation model is derived from the experimental measurements of cycle-to-cycle (C2C) and device-to-device (D2D) variations performed on FeFET devices fabricated using 28 nm high-$k$ metal gate technology. The variations were found to be a function of different conductance states within the given programming range, which sharply contrasts earlier efforts where a fixed variation dispersion was considered for all conductance values. Such variation characteristics formulated for three different device sizes at different read voltages were provided as prior variation information to the BNN to yield a more exact and reliable inference. Near-ideal accuracy for shallow networks (MLP5 and LeNet models) on the MNIST dataset and limited accuracy decline by $\sim$3.8-16.1% for deeper AlexNet models on CIFAR10 dataset under a wide range of variations corresponding to different device sizes and read voltages, demonstrates the efficacy of our proposed device-algorithm co-design technique.

We prove a quantitative version of the Gaussian Faber-Krahn type inequality proved by Betta, Chiacchio and Ferone for the first Dirichlet eigenvalue of the Ornstein-Uhlenbeck operator, estimating the deficit in terms of the Gaussian Fraenkel asymmetry. As expected, the multiplicative constant only depends on the prescribed Gaussian measure., Comment: 16 pages. arXiv admin note: text overlap with arXiv:2011.10451

The emerging field of orbitronics aims at generating and controlling currents of electronic orbital angular momentum (OAM) for information processing. Structurally chiral topological crystals could be particularly suitable orbitronic materials because they have been predicted to host topological band degeneracies in reciprocal space that are monopoles of OAM. Around such a monopole, the OAM is locked isotopically parallel or antiparallel to the direction of the electron's momentum, which could be used to generate large and controllable OAM currents. However, OAM monopoles have not yet been directly observed in chiral crystals, and no handle to control their polarity has been discovered. Here, we use circular dichroism in angle-resolved photoelectron spectroscopy (CD-ARPES) to image OAM monopoles in the chiral topological semimetals PtGa and PdGa. Moreover, we also demonstrate that the polarity of the monopole can be controlled via the structural handedness of the host crystal by imaging OAM monopoles and anti-monopoles in the two enantiomers of PdGa, respectively. For most photon energies used in our study, we observe a sign change in the CD-ARPES spectrum when comparing positive and negative momenta along the light direction near the topological degeneracy. This is consistent with the conventional view that CD-ARPES measures the projection of the OAM monopole along the photon momentum. For some photon energies, however, this sign change disappears, which can be understood from our numerical simulations as the interference of polar atomic OAM contributions, consistent with the presence of OAM monopoles. Our results highlight the potential of chiral crystals for orbitronic device applications, and our methodology could enable the discovery of even more complicated nodal OAM textures that could be exploited for orbitronics., Comment: 16 pages, 8 figures

We report efficient spin to charge conversion (SCC) in the topological insulator (TI) based heterostructure ($BiSbTe_{1.5}Se_{1.5}/Cu/Ni_{80}Fe_{20}$) by using spin-pumping technique where $BiSbTe_{1.5}Se_{1.5}$ is the TI and $Ni_{80}Fe_{20}$ is the ferromagnetic layer. The SCC, characterized by inverse Edelstein effect length ($\lambda_{IEE}$) in the TI material gets altered with an intervening Copper (Cu) layer and it depends on the interlayer thickness. The introduction of Cu layer at the interface of TI and ferromagnetic metal (FM) provides a new degree of freedom for tuning the SCC efficiency of the topological surface states. The significant enhancement of the measured spin-pumping voltage and the linewidth of ferromagnetic resonance (FMR) absorption spectra due to the insertion of Cu layer at the interface indicates a reduction in spin memory loss at the interface that resulted from the presence of exchange coupling between the surface states of TI and the local moments of ferromagnetic metal. The temperature dependence (from 8K to 300K) of the evaluated $\lambda_{IEE}$ data for all the trilayer systems, TI/Cu/FM with different Cu thickness confirms the effect of exchange coupling between the TI and FM layer on the spin to charge conversion efficiency of the topological surface state.

The radiative decay of the Hoyle state is the doorway to the production of heavier elements in stellar environment. Here we report, an exclusive measurement of electric quadruple (E$_2$) transitions of the Hoyle state to the ground state of $^{12}$C through the $^{12}$C(p, p$^\prime$$\gamma$$\gamma$)$^{12}$C reaction. Triple coincidence measurement yields a value of radiative branching ratio $\Gamma_{rad}$/$\Gamma$ = 4.01 (30) $\times$ 10$^{-4}$. The result has been corroborated by an independent experiment based on the complete kinematical measurement $via.$ $^{12}$C(p, p$^\prime$)$^{12}$C reaction ($\Gamma_{rad}$/$\Gamma$ = 4.04 (30) $\times$ 10$^{-4}$). Using our results together with the currently adopted values of $\Gamma_{\pi}$(E$_0$)/$\Gamma$ and $\Gamma_{\pi}$($E_0$), the radiative width of the Hoyle state is found to be 3.75 (40) $\times$ 10$^{-3}$ eV. We emphasize here that our result is not in agreement with 34 $\%$ increase in the radiative decay width of the Hoyle state measured recently but consistent with the currently adopted value., Comment: 7 pages, 5 figures Submitted to Phys. Rev. Lett

Axion like particles (ALPs), the pseudo Nambu-Goldstone bosons associated to the spontaneous breaking of global symmetry, have emerged as promising dark matter candidates. Conventionally, in the context of misalignment mechanism, the non-thermally produced ALPs happen to stay frozen due to Hubble friction initially and at a later stage, they begin to oscillate (before matter-radiation equality) at characteristic frequencies defined by their masses and behaving like cold dark matter. In this work, we study the influence of electroweak symmetry breaking (EWSB), through a higher order Higgs portal interaction, on the evolution of ALPs. Such an interaction is found to contribute partially to the ALP's mass during EWSB, thereby modifying oscillation frequencies during EWSB as well as impacting upon the existing correlation between the scale of symmetry breaking and their masses. The novelty of the work lies in broadening the relic satisfied parameter space so as to probe it in near future via a wide range of experiments., Comment: 13 pages, 10 figures, version to appear in PRD

This article investigates on the radial and non-radial geodesic structures of the generalized K-essence Vaidya spacetime. Within the framework of K-essence geometry, it is important to note that the metric does not possess conformal equivalence to the conventional gravitational metric. This study employs a non-canonical action of the Dirac-Born-Infeld kind. In this work, we categorize the generalized K-essence Vaidya mass function into two distinct forms. Both the forms of the mass functions have been extensively utilized to analyze the radial and non-radial time-like or null geodesics in great details inside the comoving plane. Indications of the existence of wormhole can be noted during the extreme phases of spacetime, particularly in relation to black holes and white holes, which resemble the Einstein-Rosen bridge. In addition, we have also detected the distinctive indication of the quantum tunneling phenomenon around the central singularity., Comment: 19 pages, 21 figures

One of the critical aspects for the accurate determination of neutron capture cross sections when combining time-of-flight and total energy detector techniques is the characterization and control of systematic uncertainties associated to the measuring devices. In this work we explore the most conspicuous effects associated to harsh count rate conditions: dead-time and pile-up effects. Both effects, when not properly treated, can lead to large systematic uncertainties and bias in the determination of neutron cross sections. In the majority of neutron capture measurements carried out at the CERN n\_TOF facility, the detectors of choice are the C$_{6}$D$_{6}$ liquid-based either in form of large-volume cells or recently commissioned sTED detector array, consisting of much smaller-volume modules. To account for the aforementioned effects, we introduce a Monte Carlo model for these detectors mimicking harsh count rate conditions similar to those happening at the CERN n\_TOF 20~m fligth path vertical measuring station. The model parameters are extracted by comparison with the experimental data taken at the same facility during 2022 experimental campaign. We propose a novel methodology to consider both, dead-time and pile-up effects simultaneously for these fast detectors and check the applicability to experimental data from $^{197}$Au($n$,$\gamma$), including the saturated 4.9~eV resonance which is an important component of normalization for neutron cross section measurements.