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In-plane anisotropic layered materials (ALMs), such as black phosphorus (BP), exhibit unique angle-resolved polarized Raman (ARPR) spectroscopy characteristics, as attributed to birefringence, linear dichroism and complex Raman tensor. Moreover, the ARPR intensity profiles of BP flakes deposited on multilayer dielectrics are notably sensitive to their thickness, owing to interference effects. The intricate anisotropic effects present challenges in accurately predicting the ARPR intensity of BP flakes. In this study, we propose a comprehensive strategy for predicting the ARPR intensity of BP flakes by explicitly considering optical anisotropy, encompassing birefringence, linear dichroism, and anisotropic cavity interference effects within multilayered structures. Through this approach, we have identified the intrinsic complex Raman tensors for phonon modes, independent of the BP flake thickness. By leveraging this methodology, we have elucidated the flake thickness-dependent effective complex Raman tensor elements, allowing for precise prediction of the observed ARPR intensity profile for the BP flake. This work provides a profound understanding of ARPR behaviors for ALM flakes., Comment: 6 pages, 4 figures

It has been recently established that a nonlinear valley current could be generated through traveling a surface acoustic wave (SAW) in two-dimensional Dirac materials. So far, the SAW-driven valley currents have been attributed to warping Fermi surface or Berry phase effect. Here, we demonstrate that tilt mechanism can also lead to a nonlinear valley Hall current (VHC) when propagating SAW in materials with the tilted Dirac cone placed on a piezoelectric substrate. It's found that the nonlinear VHC exhibits a $\sin\theta$ dependence on the orientation of tilt with respect to SAW. In addition, this tilt-induced nonlinear acoustic VHC shows independence on the relaxation time, distinguishing from the contributions from the Berry phase or trigonal warping. Remarkably, the magnitude of the nonlinear acoustic VHC from tilt mechanism in the uniaxially strained graphene is two orders larger than those reported in MoS$_2$ stemmed from the Berry phase effect and the warping effect., Comment: 6 pages, 2 figures, Accepted by PRB letter

An updated catalog consisting of 1092 6.7-GHz methanol maser sources was reported in this work. Additionally, the NH3 (1, 1), NH3 (2, 2), and NH3 (3, 3) transitions were observed towards 214 star forming regions using the Shanghai Tianma radio telescope (TMRT) in order to examine the differences in physical environments, such as excitation temperature and column density of molecular clouds associated with methanol masers on the Galactic scale. Statistical results reveal that the number of 6.7 GHz methanol masers in the Perseus arm is significantly lower than that in the other three main spiral arms. In addition, the Perseus arm also has the lowest gas column density among the main spiral arms traced by the NH3 observations. Both of these findings suggest that the Perseus arm has the lowest rate of high-mass star formation compared to the other three main spiral arms. We also observed a trend in which both the luminosity of 6.7 GHz methanol masers and the ammonia gas column density decreased as the galactocentric distances. This finding indicates that the density of material in the inner Milky Way is generally higher than that in the outer Milky Way. It further suggests that high-mass stars are more easily formed at the head of spiral arms. Furthermore, we found that the column density of ammonia gas is higher in the regions on the arms than that in the inter-arm regions, supporting that the former is more likely to be the birthplace of high-mass stars.

A new nonlinear magnetothermal effect, namely unidirectional Seebeck effect(USE), has been recently reported in magnetic/nonmagnetic topological insulator (TI) heterostructure and is ascribed to the asymmetry magnon scattering. Here, we show a new mechanism to generate USE in the Rashba two dimensional electron gas (2DEG), in which the magnetism or magnetic order is completely absent. It's found that the USE has a quantum origin from the spin-momentum locking generated from Rashba spin-orbit coupling. We find that the USE exhibits a sine dependence on the orientation of the magnetic field with respect to the direction of the temperature gradient and is dominant from the states above the Lifshitz point. The USE in the semiconductor Ge(111) subsurface states has been theoretically and systematically investigated., Comment: 9 pages, 4 figures

Neural network pruning is a popular model compression method which can significantly reduce the computing cost with negligible loss of accuracy. Recently, filters are often pruned directly by designing proper criteria or using auxiliary modules to measure their importance, which, however, requires expertise and trial-and-error. Due to the advantage of automation, pruning by evolutionary algorithms (EAs) has attracted much attention, but the performance is limited for deep neural networks as the search space can be quite large. In this paper, we propose a new filter pruning algorithm CCEP by cooperative coevolution, which prunes the filters in each layer by EAs separately. That is, CCEP reduces the pruning space by a divide-and-conquer strategy. The experiments show that CCEP can achieve a competitive performance with the state-of-the-art pruning methods, e.g., prune ResNet56 for $63.42\%$ FLOPs on CIFAR10 with $-0.24\%$ accuracy drop, and ResNet50 for $44.56\%$ FLOPs on ImageNet with $0.07\%$ accuracy drop.

Integrable and nonintegrable discrete nonlinear Schr\"odinger equations (NLS) are significant models to describe many phenomena in physics. Recently, Ablowitz and Musslimani introduced a class of reverse space, reverse time and reverse space-time nonlocal integrable equations, including nonlocal NLS, nonlocal sine-Gordon equation and nonlocal Davey-Stewartson equation etc. And, the integrable nonlocal discrete NLS has been exactly solved by inverse scattering transform. In this paper, we study a nonintegrable discrete nonlocal NLS which is direct discretization version of the reverse space nonlocal NLS. By applying discrete Fourier transform and modified Neumann iteration, we present its stationary solutions numerically. The linear stability of the stationary solutions is examined. Finally, we study the Cauchy problem for nonlocal NLS equation numerically and find some different and new properties on the numerical solutions comparing with the numerical solutions of the Cauchy problem for NLS equation.

This work investigates the macroscopic thermomechanical behavior of lunar boulders by modeling their response to diurnal thermal forcing. Our results reveal a bimodal, spatiotemporally-complex stress response. During sunrise, stresses occur in the boulders' interiors that are associated with large-scale temperature gradients developed due to overnight cooling. During sunset, stresses occur at the boulders' exteriors due to the cooling and contraction of the surface. Both kinds of stresses are on the order of 10 MPa in 1 m boulders and decrease for smaller diameters, suggesting that larger boulders break down more quickly. Boulders <30 cm exhibit a weak response to thermal forcing, suggesting a threshold below which crack propagation may not occur. Boulders of any size buried by regolith are shielded from thermal breakdown. As boulders increase in size (>1 m), stresses increase to several 10s of MPa as the behavior of their surfaces approaches that of an infinite halfspace. As the thermal wave loses contact with the boulder interior, stresses become limited to the near-surface. This suggests that the survival time of a boulder is not only controlled by the amplitude of induced stress, but also by its diameter as compared to the diurnal skin depth. While stresses on the order of 10 MPa are enough to drive crack propagation in terrestrial environments, crack propagation rates in vacuum are not well constrained. We explore the relationship between boulder size, stress, and the direction of crack propagation, and discuss the implications for the relative breakdown rates and estimated lifetimes of boulders on airless body surfaces., Comment: 31 pages, 12 figures

It is well known that the nonlinear Schr\"odinger (NLS) equation is a very important integrable equation. Ablowitz and Musslimani introduced and investigated an integrable nonlocal NLS equation through inverse scattering transform. Very recently, we proposed an integrable nonlocal modified Korteweg-de Vries equation (mKdV) which can also be found in a paper of Ablowitz and Musslimani. We have constructed the Darboux transformation and soliton solutions for the nonlocal mKdV equation. In this paper, we will investigate further the nonlocal mKdV equation. We will give its exact solutions including soliton and breather through inverse scattering transformation. These solutions have some new properties, which are different from the ones of the mKdV equation.

We investigate the matter power spectra in the power law and exponential types of viable $f(R)$ theories along with massive neutrinos. The enhancement of the matter power spectrum is found to be a generic feature in these models. In particular, we show that in the former type, such as the Starobinsky model, the spectrum is magnified much larger than the latter one, such as the exponential model. A greater scale of the total neutrino mass, $\Sigma m_{\nu}$, is allowed in the viable $f(R)$ models than that in the $\Lambda$CDM one. We obtain the constraints on the neutrino masses by using the CosmoMC package with the modified MGCAMB. Explicitly, we get $\Sigma m_{\nu} < 0.451 \ (0.214)\ \mathrm{eV}$ at 95% C.L. in the Starobinsky (exponential) model, while the corresponding one for the $\Lambda$CDM model is $\Sigma m_{\nu} < 0.200\ \mathrm{eV}$. Furthermore, by treating the effective number of neutrino species $N_{\mathrm{eff}}$ as a free parameter along with $\Sigma m_{\nu}$, we find that $N_{\mathrm{eff}} = 3.78^{+0.64}_{-0.84} (3.47^{+0.74}_{-0.60})$ and $\Sigma m_{\nu} = 0.533^{+0.254}_{-0.411}$ ($< 0.386) \ \mathrm{eV}$ at 95% C.L. in the Starobinsky (exponential) model., Comment: 15 pages, 5 figures, updated version accepted by PLB

A new approach is developed to calculate temperature dependent Seebeck coefficient of heavily doped systems by using Boltzmann transport theory and electron density of states (DOS) obtained from density functional calculations. This approach is applied to heavily doped La:STO with DOS from tetrahedral method and Fermi energy using Fermi integrals. The calculated Seebeck coefficient agrees with the experimental data nearly quantitatively, which proved the accuracy of this approach. The influence of the Fermi energy and asymmetry of DOS on the Seebeck coefficient is analyzed., Comment: 19 pages, 4 figures

In 2002, "Stepping Forward as Stewards of Place" identified "public engagement" as having the essential qualities of being "place-related," "interactive," "mutually beneficial" and "integrated." The publicly engaged institution was defined as being "fully committed to direct, two-way interaction with communities and other external constituencies through the development, exchange, and application of knowledge, information, and expertise for mutual benefit" (p.9). The American Association of State Colleges and Universities (AASCU) definition of public engagement is consistent with the definition used in the Carnegie Community Engagement Classification: "Community Engagement" describes "the collaboration between institutions of higher education and their larger communities (local, regional/state, national, global) for the mutually beneficial exchange of knowledge and resources in a context of partnership and reciprocity." (www.classifications.carnegiefoundation.org/descriptions/community_ engagement.php). The authors use the terms public engagement and community engagement interchangeably in this report: both involve a process of collaboration and reciprocity and a purpose of creating partnerships of university knowledge and resources with those of the public and private sectors to: enrich scholarship, research and creative activity; enhance curriculum, teaching and learning; prepare educated, engaged citizens; strengthen democratic values and civic responsibility; address critical societal issues; and contribute to the public good. The remainder of this report is organized to present the Summary Analysis and Recommendations, followed by key "areas of focus" that include key findings, examples and discussion in each area. Following the areas of focus is a section on "overall discussion and recommendations." The recommendations are designed to inform campus leaders at AASCU campuses and other engaged campuses--as well as campuses seeking the Carnegie Community Engagement Classification in the future--as to way of deepening their institutional commitment to community engagement. The analysis for this report is based on descriptive statistics of the prevalence of different practices among the AASCU community engaged campuses. The report also identifies examples--promising practices--from the applications without identifying individual institutions.