arXiv subjects

Bin Shen

Publications and source records attributed to Bin Shen.

At least 37 records · Page 2Linked to original sources

arXiv2025

Pressure-tuned spin chains in brochantite, Cu$_4$SO$_4$(OH)$_6$

Using high-pressure single-crystal x-ray diffraction combined with thermodynamic measurements and density-functional calculations, we uncover the microscopic magnetic model of the mineral brochantite, Cu$_4$SO$_4$(OH)$_6$, and its evolution upon compression. The formation of antiferromagnetic spin chains with the effective intrachain coupling of $J\simeq 100$\,K is attributed to the occurrence of longer Cu--Cu distances and larger Cu--O--Cu bond angles between the structural chains within the layers of the brochantite structure. These zigzag spin chains are additionally stabilized by ferromagnetic couplings $J_2$ between second neighbors and moderately frustrated by several antiferromagnetic couplings that manifest themselves in the reduced Néel temperature of the material. Pressure tuning of the brochantite structure keeps its monoclinic symmetry unchanged and leads to the growth of antiferromagnetic $J$ with the rate of 3.2\,K/GPa, although this trend is primarily caused by the enhanced ferromagnetic couplings $J_2$. Our results show that the nature of magnetic couplings in brochantite and in other layered Cu$^{2+}$ minerals is controlled by the size of the lattice translation along their structural chains and by the extent of the layer buckling.

cond-mat.str-el↗

arXiv2025

Pressure-induced strange metal phase in a metallic kagome ferromagnet

Strange metallicity with $T$-linear electrical resistance preceding high-$T_c$ superconductivity remains an enigmatic, yet crucial, signature of correlation physics. Using electrical transport and magnetization measurements up to 50 GPa, we show that such a strange-metal phase is formed in pressurized kagome ferromagnet CrNiAs. In contrast to other kagome materials, a linear suppression of the Curie temperature is found, with the ferromagnetic quantum critical point at $p_{\rm{c}} \approx 12.5$ GPa. Remarkably, from $p_{\rm{c}}$ up to the highest measured pressure, characteristic strange-metal behavior is observed, whereas magnetic field reinstates the Fermi liquid. Electronic structure calculations reveal robust weakly dispersive bands persisting unchanged beyond $p_{\rm{c}}$, possibly at the origin of the $T$-linear electrical resistance. This establishes pressurized kagome ferromagnets as an intriguing platform for strange-metal behavior.

cond-mat.str-el↗

arXiv2025

A Liouville-type theorem for Finslerian exponentially harmonic functions

In this manuscript, we investigate the exponentially harmonic equation on noncompact forward complete Finsler metric measure spaces. We demonstrate that this Finslerian equation represents a critical point of an exponential energy functional. Furthermore, we establish that any bounded solution to this equation is constant, provided that the mixed weighted Ricci curvature is nonnegative and certain additional non-Riemannian tensors are bounded.

math.DG↗

arXiv2025

Nonlinear eigenvalue problems for a class of quasilinear operator on complete Riemannian manifolds

In this manuscript, we study the nonlinear eigenvalue problem on complete Riemannian manifolds with Ricci curvature bounded from below, to find the unknowns $λ$ and $u$, such that $$ Qu + λf(u) = 0 $$ where $λ$ is an eigenvalue of $u$, with respect to the quasilinear operator $Qu = \operatorname{div} (\mathcal{F}(u^2, |\nabla u|^2)\nabla u)$ and nonlinar function $f(\cdot)\neq 0$. We generalize the Cheng--Yau gradient estimate in \cite{shen2025feasibilitynashmoseriterationchengyautype} and demonstrate that under certain conditions, a non-zero eigenvalue gives rise to unbounded eigenfunction $u$. Our new result also covers more quasilinear equations like $p$-porous medium equation (\textit{i.e.} $Δ_p u^q = λu^r$), and generally, $Δ_{p}\left(\sum_{i=1}^{m}a_iu^{q_i}\right)+λu^r = 0$.

math.AP↗

arXiv2025

Semantic Feature Division Multiple Access for Digital Semantic Broadcast Channels

In this paper, we propose a digital semantic feature division multiple access (SFDMA) paradigm in multi-user broadcast (BC) networks for the inference and the image reconstruction tasks. In this SFDMA scheme, the multi-user semantic information is encoded into discrete approximately orthogonal representations, and the encoded semantic features of multiple users can be simultaneously transmitted in the same time-frequency resource. Specifically, for inference tasks, we design a SFDMA digital BC network based on robust information bottleneck (RIB), which can achieve a tradeoff between inference performance, data compression and multi-user interference. Moreover, for image reconstruction tasks, we develop a SFDMA digital BC network by utilizing a Swin Transformer, which significantly reduces multi-user interference. More importantly, SFDMA can protect the privacy of users' semantic information, in which each receiver can only decode its own semantic information. Furthermore, we establish a relationship between performance and signal to interference plus noise ratio (SINR), which is fitted by an Alpha-Beta-Gamma (ABG) function. Furthermore, an optimal power allocation method is developed for the inference and reconstruction tasks. Extensive simulations verify the effectiveness and superiority of our proposed SFDMA scheme.

eess.SP↗

arXiv2025

Pressure-dependent magnetism of the Kitaev candidate Li$_2$RhO$_3$

We use magnetization measurements under pressure along with \textit{ab initio} and cluster many-body calculations to investigate magnetism of the Kitaev candidate Li$_2$RhO$_3$. Hydrostatic compression leads to a decrease in the magnitude of the nearest-neighbor ferromagnetic Kitaev coupling $K_1$ and the corresponding increase in the off-diagonal anisotropy $Γ_1$, whereas the experimental Curie-Weiss temperature changes from negative to positive with the slope of +40~K/GPa. On the other hand, spin freezing persists up to at least 3.46~GPa with the almost constant freezing temperature of 5~K that does not follow the large changes in the exchange couplings and indicates the likely extrinsic origin of spin freezing. Magnetic frustration in Li$_2$RhO$_3$ is mainly related to the interplay between ferromagnetic $K_1$ and antiferromagnetic $Γ_1$, along with the weakness of the third-neighbor coupling $J_3$ that would otherwise stabilize zigzag order. The small $J_3$ distinguishes Li$_2$RhO$_3$ from other Kitaev candidates.

cond-mat.str-el↗

arXiv2025

Feasibility of Nash-Moser iteration for Cheng-Yau-type gradient estimates of nonlinear equations on complete Riemannian manifolds

In this manuscript, we employ the Nash-Moser iteration technique to determine a condition under which the positive solution $u$ of the generalized nonlinear Poisson equation $$\operatorname{div} (φ(|\nabla u|^2)\nabla u) + ψ(u^2)u = 0,$$ on a complete Riemannian manifold with Ricci curvature bounded from below can be shown to satisfy a Cheng-Yau-type gradient estimate. We define a class of $φ$-Laplacian operators by $Δ_φ(u):=\operatorname{div} (φ(|\nabla u|^2)\nabla u)$, where $φ$ is a $C^2$ function under some certain growth conditions. This can be regarded as a natural generalization of the $p$-Laplacian, the $(p,q)$-Laplacian and the exponential Laplacian, as well as having a close connection to the prescribed mean curvature problem. We illustrate the feasibility of applying the Nash-Moser iteration for such Poisson equation to get the Cheng-Yau-type gradient estimates in different cases with various $φ$ and $ψ$. Utilizing these estimates, we proves the related Harnack inequalities and a series of Liouville theorems. Our results can cover a wide range of quasilinear Laplace operator (e.g. $p$-Laplacian for $φ(t)=t^{p/2-1}$), and Lichnerowicz-type nonlinear equations (i.e. $ψ(t) = At^{p} + Bt^{q} + Ct\log t + D$).

math.DG↗

arXiv2024

Strong enhancement of magnetic coercivity induced by uniaxial stress

The performance of permanent magnets is intricately tied to their magnetic hysteresis loop. In this study, we investigate the heavy-fermion ferromagnet CeAgSb$_2$ through magnetization measurements under uniaxial stress. We observe a 2400 % increase in magnetic coercivity with just a modest stress of approximately 1 kbar. This effect persists even after pressure release, attributable to stress-induced defects that efficiently pin domain walls. Other magnetic properties such as ordering temperature and saturation moment exhibit only weak pressure dependencies and display full reversibility. Our findings offer a promising route for increasing coercive field strength and enhancing the energy product in ferromagnetic materials and are potentially applicable to a broad spectrum of commercial or emerging magnetic applications.

cond-mat.str-el↗

arXiv2024

Intermediate field-induced phase of the honeycomb magnet BaCo$_2$(AsO$_4$)$_2$

We use magnetometry, calorimetry, and high-resolution capacitive dilatometry, as well as single-crystal neutron diffraction to explore temperature-field phase diagram of the anisotropic honeycomb magnet BaCo$_2$(AsO$_4)_2$. Our data reveal four distinct ordered states observed for in-plane magnetic fields. Of particular interest is the narrow region between 0.51 and 0.55 T that separates the up-up-down order from the fully polarized state and coincides with the field range where signatures of the spin-liquid behavior have been reported. We show that magnetic Bragg peaks persist in this intermediate phase, thus ruling out its spin-liquid nature. However, the simultaneous nonmonotonic evolution of nuclear Bragg peaks suggests the involvement of the lattice, witnessed also in other regions of the phase diagram where large changes in the sample length are observed upon entering the magnetically ordered states. Our data highlight the importance of lattice effects in BaCo$_2$(AsO$_4)_2$.

cond-mat.str-el↗

arXiv2024

The Devil is in the Sources! Knowledge Enhanced Cross-Domain Recommendation in an Information Bottleneck Perspective

Cross-domain Recommendation (CDR) aims to alleviate the data sparsity and the cold-start problems in traditional recommender systems by leveraging knowledge from an informative source domain. However, previously proposed CDR models pursue an imprudent assumption that the entire information from the source domain is equally contributed to the target domain, neglecting the evil part that is completely irrelevant to users' intrinsic interest. To address this concern, in this paper, we propose a novel knowledge enhanced cross-domain recommendation framework named CoTrans, which remolds the core procedures of CDR models with: Compression on the knowledge from the source domain and Transfer of the purity to the target domain. Specifically, following the theory of Graph Information Bottleneck, CoTrans first compresses the source behaviors with the perception of information from the target domain. Then to preserve all the important information for the CDR task, the feedback signals from both domains are utilized to promote the effectiveness of the transfer procedure. Additionally, a knowledge-enhanced encoder is employed to narrow gaps caused by the non-overlapped items across separate domains. Comprehensive experiments on three widely used cross-domain datasets demonstrate that CoTrans significantly outperforms both single-domain and state-of-the-art cross-domain recommendation approaches.

cs.IR↗

arXiv2024

Gradient estimates of the Finslerian Allen-Cahn equation

In this manuscript, we study bounded positive solutions to the Finslerian Allen-Cahn equation. The Allen-Cahn equation is widely applied and connected to many mathematical branches. We find the Finslerian Allen-Cahn equation is also an Euler-Lagrange equation to a Liapunov entropy functional. We prove the global gradient estimates of its positive solutions on compact Finsler metric measure spaces adopting the lower bounds of the weighted Ricci curvature. Moreover, as application of a new comparison theorem developed by the author, we also get a local gradient estimates on noncompact forward complete Finsler metric measure spaces with locally finite misalignment, combining with the bounds of some non-Riemannian curvatures and the lower bound mixed weighted Ricci curvature. At last, we give a Liouville type theorem of such solutions.

math.DG↗

arXiv2024

Li-Yau Estimates for a Nonlinear Parabolic Equation on Finsler Manifolds

In this paper, we explore the positive solutions to the Finslerian nonlinear equation $$\frac{\partial u}{\partial t} = Δ^{\nabla u} u + au\log u + bu,$$ which is related to Ricci solitons and serves as the Euler-Lagrange equation to the Finslerian log-energy functional. We then obtain the global gradient estimate of its positive solution on a compact Finsler metric measure space with the weighted Ricci curvature bounded below. Furthermore, using a new comparison theorem developed by the first author, we also establish a local gradient estimate on a non-compact forward complete Finsler metric measure spaces with the mixed weighted Ricci curvature bounded below, as well as finite bounds of misalignment and some non-Riemannian curvatures. Lastly, we prove the Harnack inequalities and a Liouville-type theorem of such solutions.

math.DG↗

arXiv2024

Operators on nonlinear metric measure spaces I: A New Laplacian comparison theorem on Finsler manifolds and a generalized Li-Yau approach to gradient estimates of Finslerian Schrödinger equation

This paper is the first in a series of paper where we describe the differential operators on general nonlinear metric measure spaces, namely, the Finsler spaces. We try to propose a general method for gradient estimates of the positive solutions to nonlinear parabolic (or elliptic) equations on both compact and noncompact forward complete Finsler manifolds. The key of this approach is to find a valid comparison theorem, and particularly, to find related suitable curvature conditions. Actually, we define some non-Riemannian tensors and a generalization of the weighted Ricci curvature, called the mixed weighted Ricci curvature. With the assistance of these concepts, we prove a new kind of Laplacian comparison theorem. As an illustration of such method, we apply it to Finslerian Schrödinger equation. The Schrödinger equation is a typical class of parabolic equations, and the gradient estimation of their positive solution is representative. In this paper, based on the new Laplacian comparison theorem, we give global and local Li-Yau type gradient estimates for positive solutions to the Finslerian Schrödinger equation with respect to two different mixed weighted Ricci curvature conditions.

math.DG↗

arXiv2024

Semantic Feature Division Multiple Access for Multi-user Digital Interference Networks

With the ever-increasing user density and quality of service (QoS) demand,5G networks with limited spectrum resources are facing massive access challenges. To address these challenges, in this paper, we propose a novel discrete semantic feature division multiple access (SFDMA) paradigm for multi-user digital interference networks. Specifically, by utilizing deep learning technology, SFDMA extracts multi-user semantic information into discrete representations in distinguishable semantic subspaces, which enables multiple users to transmit simultaneously over the same time-frequency resources. Furthermore, based on a robust information bottleneck, we design a SFDMA based multi-user digital semantic interference network for inference tasks, which can achieve approximate orthogonal transmission. Moreover, we propose a SFDMA based multi-user digital semantic interference network for image reconstruction tasks, where the discrete outputs of the semantic encoders of the users are approximately orthogonal, which significantly reduces multi-user interference. Furthermore, we propose an Alpha-Beta-Gamma (ABG) formula for semantic communications, which is the first theoretical relationship between inference accuracy and transmission power. Then, we derive adaptive power control methods with closed-form expressions for inference tasks. Extensive simulations verify the effectiveness and superiority of the proposed SFDMA.

eess.SP↗

arXiv2024

Magnetic versus nonmagnetic polymorphs of RuBr$_3$ under pressure

Pressure evolution of the crystal structure and magnetism of the honeycomb $α$-RuBr$_3$ is studied using high-pressure x-ray diffraction, magnetometry, and density-functional band-structure calculations. Hydrostatic compression transforms antiferromagnetic $α$-RuBr$_3$ ($R\bar 3$) into paramagnetic $α'$-RuBr$_3$ ($P\bar 1$) where short Ru-Ru bonds cause magnetism collapse above 1.3 GPa at 0 K and 2.5 GPa at 295 K. Below this critical pressure, the Néel temperature of $α$-RuBr$_3$ increases with the slope of 1.8 K/GPa. Pressure tunes $α$-RuBr$_3$ away from the Kitaev limit, whereas increased third-neighbor in-plane coupling and interlayer coupling lead to a further stabilization of the collinear zigzag state. Both $α$- and $α'$-RuBr$_3$ are metastable at ambient pressure, but their transformation into the thermodynamically stable $β$-polymorph is kinetically hindered at room temperature.

cond-mat.str-el↗

arXiv2023

Gradient estimate for Fisher-KPP equation on Finsler metric measure spaces

In this manuscript, we study the positive solutions of the Finslerian Fisher-KPP equation $$ u_t=Δ^{\nabla u} u+cu(1-u). $$ The Fisher-KPP equation is widely applied and connected to many mathematical branches. We establish the global gradient estimates on compact Finsler metric measure manifold with the traditional $CD(K,N)$ condition, which is developed by S. Ohta and K.-T. Sturm in Finsler geometry. Furthermore, With the assistance of a new comparison theorem developed by the first author, we also give the gradient estimate on forward complete noncompact locally finite misalignment Finsler metric measure spaces with the mixed weighted curvature bounded below and some non-Riemannian curvatures norm-bounded.

math.DG↗

arXiv2022

A Survey on Open-Source-Defined Wireless Networks: Framework, Key Technology, and Implementation

The realization of open-source-defined wireless networks in the telecommunication domain is accomplished through the fifth-generation network (5G). In contrast to its predecessors (3G and 4G), the 5G network can support a wide variety of heterogeneous use cases with challenging requirements from both the Internet and the Internet of Things (IoT). The future sixth-generation (6G) network will not only extend 5G capabilities but also innovate new functionalities to address emerging academic and engineering challenges. The research community has identified these challenges could be overcome by open-source-defined wireless networks, which is based on open-source software and hardware. In this survey, we present an overview of different aspects of open-source-defined wireless networks, comprising motivation, frameworks, key technologies, and implementation. We start by introducing the motivation and explore several frameworks with classification into three different categories: black-box, grey-box, and white-box. We review research efforts related to open-source-defined Core Network (CN), Radio Access Network (RAN), Multi-access Edge Computing (MEC), the capabilities of security threats, open-source hardware, and various implementations, including testbeds. The last but most important in this survey, lessons learned, future research direction, open research issues, pitfalls, and limitations of existing surveys on open-source wireless networks are included to motivate and encourage future research.

cs.NI↗

arXiv2022

A Family of Lanthanide Noncentrosymmetric Superconductors La$_4$$TX$ ($T$ = Ru, Rh, Ir; $X$ = Al, In)

We report the discovery of superconductivity in a series of noncentrosymmetric compounds La$_4$$TX$ ($T$ = Ru, Rh, Ir; $X$ = Al, In), which have a cubic crystal structure with space group $F\bar{4}3m$. La$_4$RuAl, La$_4$RhAl, La$_4$IrAl, La$_4$RuIn and La$_4$IrIn exhibit bulk superconducting transitions with critical temperatures $T_c$ of 1.77 K, 3.05 K, 1.54 K, 0.58 K and 0.93 K, respectively. The specific heat of the La$_4$$T$Al compounds are consistent with an $s$-wave model with a fully open superconducting gap. In all cases, the upper critical fields are well described by the Werthamer-Helfand-Hohenberg model, and the values are well below the Pauli limit, indicating that orbital limiting is the dominant pair-breaking mechanism. Density functional theory (DFT) calculations reveal that the degree of band splitting by the antisymmetric spin-orbit coupling (ASOC) shows considerable variation between the different compounds. This indicates that the strength of the ASOC is highly tunable across this series of superconductors, suggesting that these are good candidates for examining the relationship between the ASOC and superconducting properties in noncentrosymmetric superconductors.

cond-mat.supr-con↗