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2508.03001 2026-03-24 eess.SY cs.SY

Generation Expansion Planning with Upstream Supply Chain Constraints on Materials, Manufacturing, and Deployment

Boyu Yao, Andrey Bernstein, Yury Dvorkin

Comments 16 pages, 10 figures

Journal ref IEEE Transactions on Energy Markets, Policy and Regulation, 2026

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Rising electricity demand underscores the need for secure and reliable generation expansion planning that accounts for upstream supply chain constraints. Traditional models often overlook limitations in materials, manufacturing capacity, lead times for deployment, and field availability, which can delay availability of planned resources and thus to threaten system reliability. This paper introduces a multi-stage supply chain-constrained generation expansion planning (SC-GEP) model that optimizes long-term investments while capturing material availability, production limits, spatial and temporal constraints, and material reuse from retired assets. A decomposition algorithm efficiently solves the resulting MILP. A Maryland case study shows that supply chain constraints shift technology choices, amplify deployment delays caused by lead times, and prompt earlier investment in shorter lead-time, low-material-intensity options. In the low-demand scenario, supply chain constraints raise investment costs by $1.2 billion. Under high demand, persistent generation and reserve shortfalls emerge, underscoring the need to integrate upstream constraints into long-term planning.

2508.02745 2026-03-24 hep-ph

Functional renormalization group study of rho condensate at a finite isospin chemical potential in the quark meson model

Mohammed Osman, Defu Hou, Wentao Wang, Hui Zhang

Comments To be published in Chinese Physics C

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We investigate the effect of an isospin chemical potential ($μ_{I}$) within the quark-meson model, which approximates quantum chromodynamics (QCD) by modeling low energy phenomena such as chiral symmetry breaking and phase structure under varying conditions of temperature and chemical potential. Using the functional renormalization group (FRG) flow equations, we calculate the phase diagram in the chiral limit within the two-flavor quark-meson model in a finite $μ_{I}$ with $ρ$ vector meson interactions. Fluctuation effects significantly decrease the critical chemical potential from the mean-field (MF) value $μ_{I, MF} > m_ρ$ to lower value, at which point the $ρ$ vector meson condensates alongside the chiral condensate once the isospin chemical potential exceeds the critical value $μ_{I}^{\text{crit}}$. This $ρ$ condensation is investigated numerically for different meson coupling strengths. The $ρ$ meson dominated region is delineated from other phases by a second-order phase transition at lower $μ_{I}$ and a first-order transition at slightly higher $μ_{I}$.

2508.01367 2026-03-24 cond-mat.supr-con cond-mat.mtrl-sci cond-mat.str-el

Supercurrent Growth in Nonequilibrium Superconductors

Qinghong Yang, Yuqi Cao, Dante M. Kennes, Zhiyuan Sun

Comments 5 pages, 3 figures

Journal ref Phys. Rev. B 113, 094518(2026)

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In ultrafast experiments on superconductors, a pump laser pulse often heats up the electronic system and suppresses the density of superfluid electrons. Subsequently, the electrons undergo a cooling process because of electron-phonon thermalization so that the superfluid density recovers in time. We study the nonequilibrium electromagnetic response of the system in this cooling process. We show that if a supercurrent is initiated by a probe electric field pulse, an intriguing phenomenon of `supercurrent growth' occurs, meaning that the net current grows in time with the increasing superfluid density. Using the Boltzmann kinetic equation, we uncover its microscopic origin as the momentum-relaxing scattering of Bogoliubov quasiparticles by impurities and phonons, in stark contrast to the widely accepted intuition that impurities always attenuate currents. We further show that supercurrent growth has important experimental manifestations, including the ultrafast Meissner effect and an optical reflectivity exceeding unity.

2508.00336 2026-03-24 math.CO

Saturation for Non-Symmetric Macdonald Polynomials

Milo Bechtloff Weising, Alexander E. Black

Comments 25 pages; restructured and added several new results

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We prove that supports of non-symmetric Macdonald polynomials are $M$-convex. As a consequence, we resolve a 2019 conjecture of Monical, Tokcan, and Yong that they have the saturated Newton polytope property. As a corollary we show that affine Demazure characters of type $\mathrm{GL}$ have M-convex supports and therefore the saturated Newton polytope property answering a 2022 open question of Besson and Hong. By their results, we then find that certain affine analogs of Bruhat interval polytopes in type $\mathrm{GL}$ are generalized permutahedra. To prove these results, we find a novel interpretation of the Haglund--Haiman--Loehr formula for non-symmetric Macdonald polynomials in terms of colorings of Dyck graphs.

2507.17310 2026-03-24 math.AP

Blow-up problem for porous medium equation with absorption under nonlinear nonlocal boundary condition

Alexander Gladkov

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In this paper, we consider an initial boundary value problem for the porous medium equation with absorption under a nonlinear nonlocal boundary condition and a nonnegative initial datum. We prove the local existence of solutions, establish a comparison principle, and demonstrate both global existence and blow-up of solutions.

2507.16619 2026-03-24 cond-mat.str-el

A long-range model for the electron-nuclear coupling and two-stage order in TmVO$_4$

Sayan Ghosh, Anirudha Menon, Manoranjan Kumar, Rajiv R. P. Singh

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We study an infinite-range coupled electronic-quadrupole and nuclear-spin model for ferro-quadrupolar and nuclear-spin ordering in TmVO$_4$ in external magnetic and strain fields. This material is an experimental realization of a Transverse-Field Ising Model, where the Ising degree of freedom is quadrupolar and non-magnetic, but a transverse component is magnetic and couples both to external magnetic fields and to the nuclear spins via a hyperfine coupling. In zero external magnetic-field, there is a well-separated two-step order of the electronic and nuclear degrees of freedom and the release of their respective entropies. A transverse magnetic-field polarizes the electronic orbital moments and also the nuclear spins via the hyperfine coupling. The quadrupolar ordering temperature is gradually reduced to zero. But, there is no longer a nuclear transition in non-zero fields. Quantum fluctuations are magnified near the phase transitions and lead to peaks in the magnetic susceptibility. The spectral functions reveal a softening of a low-energy mode near the quantum critical point, consistent with the closing of the excitation gap and its reopening in the disordered phase, providing direct dynamical signatures of the field-driven quantum critical phenomena.

2507.15139 2026-03-24 math.CO

A result on spanning trees with bounded total excess

Sizhong Zhou

Comments 11 pages

Journal ref Discrete Applied Mathematics (2026)

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Let $G$ be a connected graph and $T$ a spanning tree of $G$. Let $ρ(G)$ denote the adjacency spectral radius of $G$. The $k$-excess of a vertex $v$ in $T$ is defined as $\max\{0,d_T(v)-k\}$. The total $k$-excess $\mbox{te}(T,k)$ is defined by $\mbox{te}(T,k)=\sum\limits_{v\in V(T)}{\max\{0,d_T(v)-k\}}$. A tree $T$ is said to be a $k$-tree if $d_T(v)\leq k$ for any $v\in V(T)$, that is to say, the maximum degree of a $k$-tree is at most $k$. In fact, $T$ is a spanning $k$-tree if and only if $\mbox{te}(T,k)=0$. This paper studies a generalization of spanning $k$-trees using a concept called total $k$-excess and proposes a lower bound for $ρ(G)$ in a connected graph $G$ to ensure that $G$ contains a spanning tree $T$ with $\mbox{te}(T,k)\leq b$, where $k$ and $b$ are two nonnegative integers with $k\geq\max\{5,b+3\}$ and $(b,k)\neq(2,5)$.

2507.13498 2026-03-24 astro-ph.GA

ALMA FACTS III. High-Resolution CO(2-1)/CO(1-0) Maps of Twelve Nearby Galaxies

Amanda M Lee, Jin Koda, Fumi Egusa, Akihiko Hirota, Shinya Komugi, Fumiya Maeda, Tsuyoshi Sawada

Comments Accepted for publication in ApJ

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We present early results from a high-resolution analysis ($\sim$100-200pc) of the CO(2-1)/CO(1-0) line ratio in twelve nearby galaxies. We use new ALMA CO(1-0) observations from the Fundamental CO(1-0) Transition Survey (FACTS), and re-imaged CO(2-1) data from PHANGS. We make empirical classifications based on the optical and molecular gas morphologies, which show clear systematic trends in the variation of $R_{21}$ as a function of galactic structure. The sample includes barred and unbarred, and flocculent galaxies. The barred spiral galaxies follow a general trend when the gas exists significantly: $R_{21}$ is high in the center, low along the bar, increases at the bar ends, and then lowers beyond the bar end or flattens in the outer parts of the disk. The structure dependence suggests the importance of galactic dynamics on molecular gas evolution, and consequently on star formation, in galaxies. $R_{21}$ fluctuates in the spiral arms for both barred and unbarred galaxies. Areas around HII regions in some cases appear to show more high-ratio gas. Together, $R_{21}$ varies systematically as a function of galactic structure, dynamics, and star formation activity.

2507.12764 2026-03-24 physics.flu-dyn math.AP

Unraveling Self-Similar Energy Transfer Dynamics: a Case Study for 1D Burgers System

Pritpal Matharu, Bartosz Protas, Tsuyoshi Yoneda

Comments 32 pages, 5 figures, 4 tables, code available: https://github.com/pipmath/BurgersEnergyTransfer

Journal ref Physical Review Fluids 11, 034608, 2026

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In this work we consider the problem of constructing initial conditions for a flow model such that the resulting flow evolution leads to a self-similar energy cascade consistent with Kolmogorov's statistical theory of turbulence. As a first step in this direction, we focus on the one-dimensional viscous Burgers equation as a toy model. Its solutions exhibiting self-similar behavior, in a precisely-defined sense, are found by framing this problems in terms of PDE-constrained optimization. The main physical parameters are the time window over which self-similar behavior is sought (equal to approximately one eddy turnover time), viscosity (inversely proportional to the ``Reynolds number") and an integer parameter characterizing the distance in the Fourier space over which self-similar interactions occur. Local solutions to this nonconvex PDE optimization problems are obtained with a state-of-the-art adjoint-based gradient method. Two distinct families of solutions, termed viscous and inertial, are identified and are distinguished primarily by the behavior of enstrophy which, respectively, uniformly decays and grows in the two cases. The physically meaningful and appropriately self-similar inertial solutions are found only when a sufficiently small viscosity is considered. These flows achieve the self-similar behaviour by a uniform steepening of the wave fronts present in the solutions. The results obtained demonstrate that the proposed methodology may be used to search for self-similar behavior in more complex flow models, including shell models, 2D turbulence and, ultimately, 3D turbulence.

2507.11432 2026-03-24 astro-ph.CO gr-qc

Shape of Dark Energy: Constraining Its Evolution with a General Parametrization

Dong Ha Lee, Weiqiang Yang, Eleonora Di Valentino, Supriya Pan, Carsten van de Bruck

Comments 16 pages including references; 3 tables and 6 captioned figures; version published in Phys. Rev. D

Journal ref Phys. Rev. D \textbf{113}, no.6, 063554 (2026)

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We consider a general dark energy (DE) model parametrized by its equation-of-state (EoS), featuring three free parameters: $w_0$ (the present-day value of the DE EoS), $w_β$ (quantifying the dynamical nature of the DE EoS), and $β$ (governing various dynamical forms of the DE EoS). The key controlling parameter $β$ can recover several existing DE models in the literature, such as the Chevallier-Polarski-Linder (CPL) parametrization ($β= 1$), the logarithmic parametrization (in the limit $β\rightarrow 0$), and the linear parametrization ($β= -1$), alongside generate a class of new DE parametrizations for other values of $β$. The resulting DE scenario is constrained using a suite of the latest cosmological probes, including Cosmic Microwave Background (CMB) temperature and polarization anisotropies from three different experiments (Planck 2018 and Atacama Cosmology Telescope combined with WMAP), CMB lensing, Baryon Acoustic Oscillations from DESI Year 2, and PantheonPlus from Type Ia supernovae. Our analyses reveal that stringent constraints on the DE parameters are obtained only when all cosmological probes are combined; otherwise, some parameters remain unconstrained. The present-day value of the DE EoS remains in the quintessence regime according to our results, and no significant evidence for a dynamical DE EoS is found. However, based on the $Δχ^2$ and Bayesian evidence analyses, we observe a mild preference for the present three-parameter DE parametrization over the CPL parametrization when all cosmological probes are taken into account. Nonetheless, the Bayesian evidence difference remains below the threshold for statistical significance according to the revised Jeffreys scale, indicating that both models are effectively equally preferred by the data.

2507.09526 2026-03-24 math.FA

An order-theoretic characterization of JB-algebras

Mark Roelands, Samuel Tiersma

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We give an order-theoretic characterization of the JB-algebras among the complete order unit spaces in terms of the existence of an order-anti-automorphism of the interior of the cone that is homogeneous of degree -1. More geometrically, we characterize JB-algebras as those complete order unit spaces for which the interior of the cone is a symmetric Banach--Finsler manifold under Thompson's metric. Furthermore, we show that two order unit spaces are isomorphic if there exists a gauge-reversing bijection between them, thus answering a question raised by Noll--Schäfer. These results have previously been established for finite-dimensional resp. reflexive order unit spaces by Walsh and Lemmens--R.--Wortel.

2507.07918 2026-03-24 math.AP

Strong time-periodic solutions for a multilayered fluid-structure interaction system with nonlinear coupling

Felix Brandt, Claudiu Mîndrilă, Arnab Roy

Comments Accepted for publication in Nonlinearity

Journal ref Nonlinearity 39 (2026), Paper No. 035018

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We investigate a time-periodic fully three-dimensional fluid-structure interaction system in which the Navier-Stokes equations for an incompressible viscous fluid are coupled with a multilayered elastic structure composed of a damped thin linear plate and a thick viscoelastic layer. The coupling is nonlinear, meaning that it is on a moving interface that is not known a priori, rendering the problem a moving-domain problem. We prove the existence of strong time-periodic solutions. The proof relies on a fixed point argument, combining sharp nonlinear estimates with a detailed analysis of the linearized system. The linearized problem is analyzed by employing the Arendt-Bu theorem on maximal periodic $\mathrm{L}^p$-regularity, which requires several new analytical ingredients including a refined lifting procedure, a decoupling strategy establishing $\mathcal{R}$-sectoriality of the coupled operator, a careful treatment of the thick structural layer, and a spectral analysis adapted to the multilayered setting. This provides the first strong time-periodic existence result for multilayered fluid-structure interaction systems, and the methods are expended to extend more broadly to nonlinear coupled PDEs on moving domains with periodic forcing.

2507.04672 2026-03-24 math.OC

Bounds for the number of basic feasible solutions generated by the simplex method with the largest distance rule

Tomonari Kitahara

Comments 10pages, comments are welcomed!

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In this paper, we analyze the simplex method with the largest distance rule and derive upper bounds on the number of different basic feasible solutions generated. The pivoting rule was proposed by Pan [10], and in some cases, it was reported to be more efficient than the renowned steepest edge rule. We show that the analytical framework developed by Kitahara and Mizuno can be extended to this rule, despite its structural differences from previously studied pivoting rules. The resulting bounds involve a geometric parameter $β$ determined by the column norms of the constraint matrix. In addition, our analysis does not require a nondegeneracy assumption.

2507.02538 2026-03-24 hep-ph nucl-th

Matching from quark to hadronic operators: external source vs spurion methods

Gang Li, Chuan-Qiang Song, Jiang-Hao Yu

Comments v1: 51 pages, 9 tables. v2: added discussions on relations of LECs for chiral operators in the systematic spurion method; matches the published version in JHEP

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Various weak processes at the hadronic scale have been utilized to search for new physics at high energy scale, which can be described by the QCD chiral Lagrangian matched from the low-energy effective theory (LEFT). Utilizing the chiral symmetry $SU(2)_L\times SU(2)_R \to SU(2)_V$ at the quark and hadronic levels, we make a comprehensive comparison of various matching methods, including the external source method, conventional spurion method, and our systematic spurion method. Although different methods show agreements for dimension-6 LEFT operator matching, we find that for higher-dimensional operators, the external source method is quite limited or inapplicable, the conventional spurion methods needs to introduce more and more spurions, while our spurion method does not need to introduce any new spurions than the ones in the dimension-6 matching. Using minimal set of spurions, we thus establish an one-to-one correspondence between the LEFT and chiral operators, with several examples, such as derivative operators at dimensions 7 and 8 with a single bilinear, four-quark operators at the dimension-9 level with two quark bilinears, which can be applied to the study of neutrino/electron scatterings and neutrinoless double beta decay.

2506.23814 2026-03-24 cs.CR

Beyond the TESSERACT:Trustworthy Dataset Curation for Sound Evaluations of Android Malware Classifiers

Theo Chow, Mario D'Onghia, Lorenz Linhardt, Zeliang Kan, Daniel Arp, Lorenzo Cavallaro, Fabio Pierazzi

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The reliability of machine learning critically depends on dataset quality. While machine learning applied to computer vision and natural language processing benefits from high-quality benchmark datasets, cyber security often falls behind, as quality ties to the ability of accessing hard-to-obtain realistic data that may evolve over time. Android is, however, positioned uniquely in this ecosystem due to AndroZoo and other sources, which provide large-scale, continuously updated, and timestamped repositories of benign and malicious apps. Since their release, such data sources provided access to populations of Android apps that researchers can sample from to evaluate learning-based methods in realistic settings, i.e., over temporal frames to account for app evolution (natural distribution shift) and test datasets that reflect in-the-wild class ratios. Surprisingly, we observe that despite this abundance of data, performance discrepancies of learning-based Android malware detectors still persist even after satisfying such realistic requirements, which challenges our ability to understand what the state of the art in this field is. In this work, we identify five novel factors that influence such discrepancies: we show how such factors have been largely overlooked and the impact they have on providing sound evaluations. Our findings and recommendations help define a methodology for curating trustworthy datasets towards sound evaluations of Android malware classifiers.

2506.23457 2026-03-24 cs.HC

Driving Path Indication Reduces Motion Sickness and Influences Head Motion of Passengers in Autonomous Personal Mobility Vehicle

Yuya Ide, Hailong Liu, Takahiro Wada

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Autonomous personal mobility vehicles (APMVs) are novel smart mobility devices designed to provide automated individual transportation in indoor or mixed-traffic environments. However, in such environments, frequent pedestrian avoidance maneuvers may cause rapid steering adjustments and passive postural responses from passengers, thereby increasing the risk of motion sickness. This study investigated whether indicating the future driving path could mitigate motion sickness in APMV passengers. A mixed-design experiment was conducted with 40 participants under two self-reported genders as a between-subject factor (male and female), two driving paths as a between-subject factor (irregular and regular) and three driving conditions as a within-subject factor (manual driving (MD), automated driving without path indication (AD w/o path), and automated driving with path indication (AD w/ path)). Motion sickness was evaluated using the Motion Illness Symptom Classification (MISC), and head motion was assessed by calculating the delay time of participants' head yaw rate relative to APMV's yaw rate in the turning direction. The results showed that driving condition was the only factor that significantly affected both motion sickness and head-motion delay. Compared with the AD w/o path condition, both the MD and AD w/ path conditions were associated with lower motion sickness severity, longer motion sickness onset latency, and earlier head motion relative to vehicle motion. Notably, the AD w/ path condition achieved motion sickness levels comparable to those in the MD condition. Furthermore, repeated-measures correlation analysis showed significant associations between head-motion delay and all MISC metrics but the underlying physiological mechanism remains to be elucidated. These findings suggest that presenting information about future driving path can mitigate motion sickness in APMV passengers.

2506.22823 2026-03-24 math.DS math.PR

Concentration inequalities for random dynamical systems

Graccyela Salcedo

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We establish concentration inequalities for random dynamical systems (RDSs), assuming that the observables of interest are separately Lipschitz. Under a weak average contraction condition, we obtain deviation bounds for several random quantities, including time-average synchronization, empirical measures, Birkhoff sums, and correlation dimension estimators. We present concrete classes of RDSs to which our main results apply, such as finitely supported diffeomorphisms on the circle and projective systems induced by linear cocycles. In both cases, we obtain concentration inequalities for finite-time Lyapunov exponents.

2506.22687 2026-03-24 cs.LO

Compositional Control-Driven Boolean Circuits

Damian Arellanes

Comments Full version of a paper accepted at RAMICS 2026. It includes all proofs and appendix material from the original submission, which were peer-reviewed but omitted from the proceedings version due to space constraints. In the proceedings version, only the proofs of Theorems 6 and 7 and Proposition 7 are included. The Version of Record is available at: https://doi.org/10.1007/978-3-032-22469-9_2

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Boolean circuits abstract away from physical details to focus on the logical structure and computational behaviour of digital components. Although such circuits have been studied for many decades, compositionality has been widely ignored or examined in an informal manner, which is a property for combining circuits without delving into their internal structure, while supporting modularity and formal reasoning. In this paper, we address this longstanding theoretical gap by proposing colimit-based operators for compositional circuit construction. We define separate operators for forming sequential, parallel, branching and iterative circuits. As composites encapsulate explicit control flow, a new model of computation emerges which we refer to as (families of) control-driven Boolean circuits. We show how this model is at least as powerful as its classical counterpart. In other words, it is able to non-uniformly compute any Boolean function on inputs of arbitrary length.

2506.22417 2026-03-24 cond-mat.mes-hall cond-mat.mtrl-sci cond-mat.str-el

Quantum-geometric dipole: a topological boost to flavor ferromagnetism in flat bands

Lei Chen, Sayed Ali Akbar Ghorashi, Jennifer Cano, Valentin Crépel

Comments 9+9 pages, 3+2 figures

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Robust flavor-polarized phases are a striking hallmark of many flat-band moiré materials. In this work, we trace the origin of this spontaneous polarization to a lesser-known quantum-geometric quantity: the quantum-geometric dipole. Analogous to how the quantum metric governs the spatial spread of wavepackets, we show that the quantum-geometric dipole sets the characteristic size of particle-hole excitations, e.g. magnons in a ferromagnet, which in turn boosts their gap and stiffness. Indeed, the larger the particle-hole separation, the weaker the mutual attraction, and the stronger the excitation energy. In topological bands, this energy enhancement admits a lower bound within the local-mode approximation, highlighting the crucial role of topology in flat-band ferromagnetism. We illustrate these effects in microscopic models, emphasizing their generality and relevance to moiré materials. Our results establish the quantum-geometric dipole as a predictive geometric indicator for ferromagnetism in flat bands, a crucial prerequisite for topological order.

2506.20976 2026-03-24 math.CO

Eigenvalue bounds for distance-edge colorings

Aida Abiad, Harper Reijnders

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For a fixed positive integer $t$, we consider the graph colouring problem in which edges at distance at most $t$ are given distinct colours. We obtain sharp lower bounds for the distance-$t$ chromatic index, the least number of colours necessary for such a colouring. Our bounds are of algebraic nature; they depend on the eigenvalues of the line graph and on a polynomial which can be found using integer linear programming methods. We show several graph classes that attain equality for our bounds, and also present some computational results which illustrate the bound's performance. Lastly, we investigate the implications the spectral approach has to the Erdős-Nešetřil conjecture, and derive some conditions which a graph must satisfy if we could use it to obtain a counter example through the proposed spectral methods.

2506.20366 2026-03-24 physics.app-ph cond-mat.mtrl-sci

Electrically-gated laser-induced spin dynamics in magneto-electric iron garnet at room temperature

T. T. Gareev, N. E. Khokhlov, L. Körber, A. P. Pyatakov, A. V. Kimel

Comments 6 pages, 6 figures

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Ultrafast pump-probe imaging reveals that the efficiency of optical excitation of coherent spins waves in epitaxial iron garnet films can be effectively controlled by an external electric field at room temperature. Although a femtosecond laser pulse alone does not excite any pronounced coherent spin oscillations, an electrical gating with the field of 0.5 MV/m dramatically changes the outcome in a laser-induced launching of spin waves. The effect, demonstrated under room-temperature conditions, is estimated to be orders of magnitude larger than in magnetic van der Waals semiconductors observed at 10 K. This electrical gating of laser-induced spin dynamics enriches opto-magnonics with a new tool and thus opens up a new avenue in fundamental and applied magnonics research.

2506.20223 2026-03-24 physics.optics

Efficient first-principles inverse design of nanolasers

Beñat Martinez de Aguirre Jokisch, Alexander Cerjan, Rasmus Ellebæk Christiansen, Jesper Mørk, Ole Sigmund, Steven G. Johnson

Journal ref Laser Photonics Reviews e01614 (2025)

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We develop and demonstrate a first-principles approach, based on the nonlinear Maxwell-Bloch equations and steady-state ab-initio laser theory (SALT), for inverse design of nanostructured lasers, incorporating spatial hole-burning corrections, threshold effects, out-coupling efficiency, and gain diffusion. The resulting figure of merit exploits the high-$Q$ regime of optimized laser cavities to perturbatively simplify the nonlinear model to a single linear ''reciprocal'' Maxwell solve. The consequences for laser-cavity design, and in particular the strong dependence on the nature of the gain region, are demonstrated using topology optimization of both 2d and full 3d geometries.

2506.14967 2026-03-24 cond-mat.mes-hall

Quasi-1D Coulomb drag between spin-polarized quantum wires

Mingyang Zheng, Rebika Makaju, Rasul Gazizulin, Alex Levchenko, Sadhvikas J. Addamane, Dominique Laroche

Comments 7 pages, 4 figures

Journal ref Phys. Rev. B 113, L121408 (2026)

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One-dimensional (1D) quantum wires provide a versatile platform for studying strong electron-electron interactions and collective excitations under confinement. Coulomb drag between 1D systems offers a powerful probe of Tomonaga-Luttinger liquid (TLL) physics, with theoretical predictions suggesting distinct power-law in temperature dependencies between the spin-full and the spin-polarized regimes. However, experimental verification has thus far remained limited. Here, we report measurements of reciprocal and nonreciprocal Coulomb drag between vertically coupled quasi-1D quantum wires in the spin-polarized regime. Clear signatures of spin splitting are observed in both the wires conductance and the drag signal. We observed a connection between electron-hole asymmetry and negative drag, and demonstrated different power-law behaviors in spin-full and spin-polarized regimes, yielding consistent TLL interaction parameters. These results validate the theoretical predictions for backscattering induced drag in the reciprocal regime and extend them to the nonreciprocal and the multiple subband regimes. Furthermore, the nonmonotonic density dependence of the reciprocal interaction parameter correlates with the subband occupation of the drag wire, revealing the complexity of the scattering mechanisms in multichannel systems.

2506.14082 2026-03-24 physics.geo-ph stat.AP

Smooth surface reconstruction of earthquake faults from distributed moment-potency-tensor solutions

Dye SK Sato, Yuji Yagi, Ryo Okuwaki, Yukitoshi Fukahata

Comments 46 pages, 13 figures

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Earthquake faults as observed by seismic motions primarily manifest as displacement discontinuities within elastic continua. The displacement discontinuity and the surface normal vector (n-vector) of such an idealized earthquake source are measured by the tensor of potency, which is seismic moment normalized by stiffness. This study formulates an inverse problem to reconstruct a smooth 3D fault surface from an areal density field of the potency tensor. Here, the surface is represented by an elevation field, while nodal planes of the potency density represent the surface normal (n-vector) field, reducing the problem to an n-vector-to-elevation transform. Although this transform is a one-to-one mapping in 2D, it becomes overdetermined in 3D because the n-vector has two degrees of freedom while the scalar elevation has only one, admitting no solution in general. This overdeterminacy originates from modeling the potency density, the inelastic strain with six degrees of freedom, as a displacement discontinuity of five degrees of freedom. Whereas this overdeterminacy appears as the violation of the determinant-free constraint in point potency sources, it raises a conflict with the global consistency of the n-vector field in areal potency densities. Recognizing this capacity of the potency density to describe inelastic strain incompatible with displacement discontinuity, we introduce an a priori constraint to define the fault as the smooth surface that best approximates inelastic strain as displacement discontinuity. We derive an analytical solution for this formulation and demonstrate its ability to reproduce 3D surfaces from noisy synthetic n-vectors. We integrate this formula into potency density tensor inversion and apply it to the 2013 Balochistan earthquake. The estimated 3D geometry shows better agreement with observed fault traces than previous quasi-2D methods, validating our proposal.

2506.13872 2026-03-24 quant-ph gr-qc

Gravitational wave imprints on spontaneous emission

Jerzy Paczos, Navdeep Arya, Sofia Qvarfort, Daniel Braun, Magdalena Zych

Comments 5+10 pages, 1 figure; published in Physical Review Letters

Journal ref Phys. Rev. Lett. 136, 113201 (2026)

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Despite growing interest, there is a scarcity of known predictions in the regime where both quantum and general relativistic effects become observable. Here, we investigate a combined atom-field system in a curved spacetime, with a specific focus on gravitational-wave backgrounds. We demonstrate that a plane gravitational wave alters spontaneous emission from a single atom, manifesting itself as a direction-dependent change in the emission spectrum. Although the total decay rate remains unchanged, implying that no information about the gravitational wave is stored in the atomic internal state alone, the wave leaves imprints on the evolution of the composite atom-field system. To quantify how well this effect can be measured, we analyze both the classical Fisher information associated with photon number measurements and the quantum Fisher information. Our analysis indicates that the effect could be measured in state-of-the-art cold-atom experiments and points to spontaneous emission as a potential probe of low-frequency gravitational waves.

2506.12629 2026-03-24 physics.comp-ph cs.CE cs.MS physics.chem-ph quant-ph

The Software Landscape for the Density Matrix Renormalization Group

Per Sehlstedt, Jan Brandejs, Paolo Bientinesi, Lars Karlsson

Comments [v2] Added two more packages

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The density matrix renormalization group (DMRG) algorithm is a cornerstone computational method for studying quantum many-body systems, renowned for its accuracy and adaptability. Despite DMRG's broad applicability across fields such as materials science, quantum chemistry, and quantum computing, numerous independent implementations have been developed. This survey maps the rapidly expanding DMRG software landscape, providing a comprehensive comparison of features among 35 existing packages. We found significant overlap in features among the packages when comparing key aspects, such as parallelism strategies for high-performance computing and symmetry-adapted formulations that enhance efficiency. This overlap suggests opportunities for modularization of common operations, including tensor operations, symmetry representations, and eigensolvers, as the packages are mostly independent and share few third-party library dependencies where functionality is factored out. More widespread modularization and standardization would result in reduced duplication of efforts and improved interoperability. We believe that the proliferation of packages and the current lack of standard interfaces and modularity are more social than technical. We aim to raise awareness of existing packages, guide researchers in finding a suitable package for their needs, and help developers identify opportunities for collaboration, modularity standardization, and optimization. Ultimately, this work emphasizes the value of greater cohesion and modularity, which would benefit DMRG software, allowing these powerful algorithms to tackle more complex and ambitious problems.

2506.11885 2026-03-24 quant-ph

Fast and High Excitation Transport in Waveguide Quantum Electrodynamics

Ya-Tang Yu, I Gusti Ngurah Yudi Handayana, Wei Chen, H. H. Jen

Comments 12 figures

Journal ref New J. Phys. 28, 034501 (2026)

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英文摘要

Waveguide quantum electrodynamics (wQED) with underlying collective and long-range atom-atom interactions has led to many distinct dynamical phenomena, including modified collective radiations and intriguing quantum correlations. It stands out as a unique platform to illustrate correlated photon transport, as well as to promise applications in quantum information processing. Here we manifest a fast and high atomic excitation transport by employing two separated chirally-coupled atomic arrays. This enhanced waveguide-mediated transport of excitations emerges due to the dominance of few subradiant right eigenstates that are spectrally isolated and spatially localized in the system's dynamics. Contrary to the instinct of applying the cascaded systems with unidirectional couplings to expedite direct and high excitation transport, the optimal system configurations in open wQED systems demand slight or finite nonreciprocal decay channels to facilitate energy transport by exploiting waveguide-mediated couplings. We also investigate the effect of the couplings' directionality and the scaling of atom number on the transport properties. Our results showcase the wide applicability in wQED platforms and provide insights into quantum engineering and quantum information applications.

2506.07708 2026-03-24 math.OC math.MG

Shape optimization under width constraint: the Cheeger constant and the torsional rigidity

Beniamin Bogosel

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英文摘要

In this article it is shown that the equilateral triangle maximizes the Cheeger constant and minimizes the torsional rigidity among shapes having a fixed minimal width. The proof techniques use direct comparisons with simpler shapes, consisting of disks with three disjoint caps. Comparison results for harmonic functions help establish that in non-equilateral configurations the shape derivative has an appropriate sign, contradicting optimality.

2506.06655 2026-03-24 hep-ph astro-ph.CO

Composite Hybrid Inflation : Primordial Black Holes and Stochastic Gravitational Waves

Giacomo Cacciapaglia, Dhong Yeon Cheong, Aldo Deandrea, Wanda Isnard, Seong Chan Park, Xinpeng Wang, Ying-li Zhang

Comments 29 pages, 17 figures, matches JCAP version

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英文摘要

We investigate the production of primordial black holes and gravitational waves in composite hybrid inflation. Starting from an effective chiral Lagrangian with a dilaton and pions, we identify inflation occurring due to the walking dynamics of the theory. A $\mathbb{Z}_2$ symmetry-breaking term in the pion sector induces a shift in the inflaton's trajectory, which leads to a tachyonic instability phase. Curvature perturbations grow exponentially, producing copious primordial black holes and a stochastic gravitational wave background. We show that the primordial black hole mass and the gravitational wave frequency are strongly restricted by the anomalous dimensions of the pion operators, with larger anomalous dimensions giving lighter primordial black holes and higher frequency gravitational waves. In both cases, the associated signatures lie within reach of future gravitational wave observatories.

2506.05849 2026-03-24 nucl-th hep-ph

Femtoscopic signatures of unique nuclear structures in relativistic collisions

Daniel Kincses

Comments 8 pages, 5 figures

Journal ref Phys.Rev.Res. 7 (2025) 4, L042028

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英文摘要

One of the most vital topics of today's high-energy nuclear physics is the investigation of the nuclear structure of the collided nuclei. Recent studies at the Relativistic Heavy Ion Collider (RHIC) and the Large Hadron Collider (LHC) have shown that several observables, such as the collective flow and transverse-momentum correlations of the produced particles, can be sensitive to various nuclear structure and deformation parameters. Femtoscopy, another essential tool for investigating the space-time geometry of the matter created in nuclear collisions, has not yet been widely applied to such studies. Using a multiphase transport model (AMPT), in this Letter, it is demonstrated that the femtoscopic source parameters of pion pairs can also serve as a robust signal of unique nuclear structure. Through an analysis of $^{208}$Pb+$^{20}$Ne and $^{208}$Pb+$^{16}$O collisions at $\sqrt{s_{NN}}$ = 68.5 GeV, two collision systems especially relevant to the SMOG2 program of the LHCb experiment, it is shown that a deformed initial shape can significantly affect femtoscopic source parameters. This study highlights the importance of expanding the nuclear structure investigations to femtoscopic observables and serves as a baseline for numerous possible future studies in this new direction.