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2410.04821 2026-03-27 physics.ao-ph

The absolute seawater entropy: Part I. Definition

Pascal Marquet

Comments V1: First submitted on the 7th of October 2024. V2: arXiv reference for the Part-II. V3: First Revised version. V4: Accepted in the Comptes Rendus (Geoscience) Paris, France on the 23th of March, 2026 (3 Figures; 27 pages)

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The first improvements concern the complex non-linear dependence of entropy on pressure, temperature and salinity, with the use of the standard TEOS10 formulation based on a fit of the oceanic Gibbs function to more recent observations. On the other hand, more recent thermodynamic tables have been used to increase the accuracy of the Millero's salinity increment to this standard formulation, to deduce the absolute version of entropy with new values for the pure-water and sea-salts absolute reference entropies. The differences between the values of the seawater entropy calculated with the Millero and TEOS10 formulations (standard and absolute) are documented, before a more complete study shown in the second part of the paper of the absolute seawater entropy computed from observed vertical profiles and analysed surface datasets.

2409.14126 2026-03-27 physics.optics

Temperature-dependent mechanical losses of Eu$^{3+}$:Y$_{2}$SiO$_{5}$ for spectral hole burning laser stabilization

Nico Wagner, Johannes Dickmann, Bess Fang, Michael T. Hartman, Stefanie Kroker

Comments 7 pages, 5 figures

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We investigate the mechanical loss characteristics of Eu$^{3+}$:Y$_2$SiO$_5$$\unicode{x2013}$a promising candidate for ultra-low-noise frequency stabilization through the spectral hole burning technique. Three different mechanical oscillators with varying surface-to-volume ratios and crystal orientations are evaluated. In this context, we perform mechanical ringdown and spectral measurements spanning temperatures from room temperature down to $15\,\mathrm{K}$. By doing so, we measure a maximum mechanical quality factor of $Q=3676$, corresponding to a loss angle of $ϕ=2.72\times 10^{-4}$. For a spectral hole burning laser stabilization experiment at $300\,\mathrm{mK}$, we can estimate the Allan deviation of the fractional frequency instability due to Brownian thermal noise to be below $σ_{δν/ν_0} = 2.5\times 10^{-18}$, a value lower than the estimated thermal-noise limit of any current cavity-referenced ultra-stable laser experiment.

2409.14120 2026-03-27 physics.optics

Mechanical loss and stability analysis of NEXCERA in ultra-stable optical cavities

Nico Wagner, Mateusz Narożnik, Marcin Bober, Steffen Sauer, Michał Zawada, Stefanie Kroker

Comments 13 pages, 7 figures

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NEXCERA has emerged as a ceramic-based material for spacers in ultra-stable optical cavities, with a coefficient of thermal expansion that crosses zero near room temperature. In such cavities, frequency stability is ultimately limited by Brownian thermal noise in the cavity components. A key parameter in this context is the mechanical loss, which has remained unknown for NEXCERA. In this work, we investigate the mechanical loss of NEXCERA N117B at room temperature for various resonances using the gentle nodal suspension technique. We measure a promising minimum mechanical loss of $ϕ= 1.89\times 10^{-5}$, indicating the suitability of NEXCERA for low-noise optical cavities. Using this value, we calculate the thermal noise of a cavity with a NEXCERA spacer and compare its performance to established materials such as ULE and Zerodur, taking into account different mirror substrate options. Our analysis shows that NEXCERA is a strong candidate for ultra-stable cavities due to its low thermal noise. Combined with its previously reported low linear drift, it offers a highly attractive option for long-term stable optical frequency references.

2407.11620 2026-03-27 eess.SP

A Deep Learning-Based Target Radial Length Estimation Method through HRRP Sequence

Lingfeng Chen, Panhe Hu, Zhiliang Pan, Xiao Sun, Zehao Wang

Comments 2 pages, 2 figures. Accepted by APCAP 2024

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This paper introduces an innovative deep learning-based method for end-to-end target radial length estimation from HRRP (High Resolution Range Profile) sequences. Firstly, the HRRP sequences are normalized and transformed into GAF (Gram Angular Field) images to effectively capture and utilize the temporal information. Subsequently, these GAF images serve as the input for a pretrained ResNet-101 model, which is then fine-tuned for target radial length estimation. The simulation results show that compared to traditional threshold method and simple networks e.g. one-dimensional CNN (Convolutional Neural Network), the proposed method demonstrates superior noise resistance and higher accuracy under low SNR (Signal-to-Noise Ratio) conditions.

2407.08236 2026-03-27 eess.SP

HRRPGraphNet: Make HRRPs to Be Graphs for Efficient Target Recognition

Lingfeng Chen, Xiao Sun, Zhiliang Pan, Zehao Wang, Xiaolong Su, Zhen Liu, Panhe Hu

Comments 3 pages, 3 figures. Accepted by IET Electronics Letters

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High Resolution Range Profiles (HRRP) have become a key area of focus in the domain of Radar Automatic Target Recognition (RATR). Despite the success of deep learning based HRRP recognition, these methods needs a large amount of training samples to generate good performance, which could be a severe challenge under non-cooperative circumstances. Currently, deep learning based models treat HRRP as sequences, which may lead to ignorance of the internal relationship of range cells. This letter introduces HRRPGraphNet, whose pivotal innovation is the transformation of HRRP data into a novel graph structure, utilizing a range cell amplitude(hyphen)based node vector and a range(hyphen)relative adjacency matrix. This graph(hyphen)based approach facilitates both local feature extraction via one(hyphen)dimensional convolution layers, global feature extraction through a graph convolution layer and a attention module. Experiments on the aircraft electromagnetic simulation dataset confirmed HRRPGraphNet superior accuracy and robustness, particularly in limited training sample environments, underscoring the potential of graph(hyphen)driven innovations in HRRP(hyphen)based RATR.

2407.07555 2026-03-27 hep-th

Conformal bootstrap and Mirror symmetry of states in Gepner models

Sergej Parkhomenko

Comments reference and minor comments added

Journal ref JHEP 11 (2024) 104

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We consider two explicit constructions of states in the orbifolds of a product of Minimal $N=(2,2)$ models which are based on twisting by spectral flow, mutual locality and operator algebra requirement. It is shown that these two constructions lead to the Berglund-Hubsh-Krawitz dual orbifold groups which define mirror pairs of isomorphic models. Then we generalize our construction for the orbifolds of Gepner models of superstring compactification and explicitly build IIA/IIB mirror map of the space of states of the superstrings using light-cone gauge.

2407.06640 2026-03-27 hep-ph gr-qc

Higgs-like field interactions before symmetry breaking

Jerzy Paczos, Szymon Cedrowski, Krzysztof Turzyński, Andrzej Dragan

Comments 4+2 pages; published in Nuclear Physics B

Journal ref Nuclear Physics B 1024 (2026) 117351

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We investigate the Brout-Englert-Higgs mechanism of spontaneous symmetry breaking and show that, before symmetry breaking, the interaction of Higgs fields with massless gauge fields leads to the production of particles with negative squared mass.

2406.15853 2026-03-27 quant-ph

Repeater-like asynchronous measurement-device-independent quantum conference key agreement

Yu-Shuo Lu, Hua-Lei Yin, Yuan-Mei Xie, Yao Fu, Zeng-Bing Chen

Comments 28 pages, 9 figures

Journal ref Rep. Prog. Phys. 88, 067901 (2025)

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Quantum conference key agreement enables secure communication among multiple parties by leveraging multipartite entanglement, which is expected to play a crucial role in future quantum networks. However, its practical implementation has been severely limited by the experimental complexity and low efficiency associated with the requirement for synchronous detection of multipartite entangled states. In this work, we propose a measurement-device-independent quantum conference key agreement protocol that employs asynchronous Greenberger-Horne-Zeilinger state measurement. Our protocol enables a linear scaling of the conference key rate among multiple parties, demonstrating performance comparable to that of the single-repeater scheme in quantum networks. Additionally, we achieve intercity transmission distances with composable security under finite-key conditions. By adopting the generalized asynchronous pairing strategy, our approach eliminates the need for complex global phase locking techniques. Furthermore, by integrating asynchronous pairing with ring-interference network structure, our method provides insights for various quantum tasks beyond quantum communication, including multiparty computing and quantum repeaters.

2406.06361 2026-03-27 quant-ph math.OC

Challenges with Differentiable Quantum Dynamics

Sri Hari Krishna Narayanan, Michael Perlin, Robert Lewis-Swan, Jeffrey Larson, Matt Menickelly, Jan Hückelheim, Paul Hovland

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Differentiable quantum dynamics require automatic differentiation of a complex-valued initial value problem, which numerically integrates a system of ordinary differential equations from a specified initial condition, as well as the eigendecomposition of a matrix. We explored several automatic differentiation frameworks for these tasks, finding that no framework natively supports our application requirements. We therefore demonstrate a need for broader support of complex-valued, differentiable numerical integration in scientific computing libraries.

2406.04790 2026-03-27 math.AP

On the location of the maximal gradient of the torsion function over some non-symmetric planar domains

Qinfeng Li, Shuangquan Xie, Hang Yang, Ruofei Yao

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We investigate the location of the maximal gradient of the torsion function on certain non-symmetric planar domains. First, by establishing uniform estimates for convex narrow domains, we show that as a planar domain bounded by two graphs becomes increasingly narrow, the location of the maximal gradient of its torsion function converges to the endpoints of the longest vertical segment, with smaller curvature among them. This result confirms that Saint-Venant's conjecture on the location of fail points holds for asymptotically narrow domains. Second, for triangles, we prove that the maximal gradient of the torsion function always occurs on the longest side, lying between the foot of the altitude and the midpoint of that side. Moreover, via nodal line analysis, we show that, restricted to each side, the critical point of the gradient is unique and non-degenerate. Additionally, by perturbation and barrier arguments, we establish that for a class of nearly equilateral triangles, this critical point is closer to the midpoint than to the foot of the altitude, and the maximal gradient at the midpoint exceeds that at the foot of the altitude. Third, employing the reflection method, we demonstrate that for a non-concentric annulus, the maximal gradient of the torsion function is always attained at the point on the inner boundary closest to the center of the outer boundary.

2405.04951 2026-03-27 math.PR

Gaussian consensus processes and their Lyapunov exponents

Edward Crane, Stanislav Volkov

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We introduce a simple dynamic model of opinion formation, in which a finite population of individuals hold vector-valued opinions. At each time step, each individual's opinion moves towards the mean opinion but is then perturbed independently by a centred multivariate Gaussian random variable, with covariance proportional to the covariance matrix of the opinions of the population. We establish precise necessary and sufficient conditions on the parameters of the model, under which all opinions converge to a common limiting value. Asymptotically perfect correlation emerges between opinions on different topics. Our results are rigorous and based on properties of the partial products of an i.i.d. sequence of random matrices. Each matrix is a fixed linear combination of the identity matrix and a real Ginibre matrix. We derive an analytic expression for the maximal Lyapunov exponent of this product sequence. We also analyze a continuous-time analogue of our model.

2405.01295 2026-03-27 quant-ph

Inverse Current in Coupled Transport: A Quantum Thermodynamic Model

Shuvadip Ghosh, Nikhil Gupt, Arnab Ghosh

Comments 18 pages, 6 figures

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The recent discovery of inverse current in coupled transport (ICC) in classical systems~\textcolor{blue}{[\textbf{Phys. Rev. Lett.} \textbf{124}, 110607 (2020)]} -- where an induced current flows opposite to two mutually parallel thermodynamic forces, yet remains consistent with the second law of thermodynamics -- reveals a striking and counterintuitive transport phenomenon. Using an exactly solvable model of strongly coupled quantum dots, we develop a thermodynamic framework to describe the ICC phenomenon at the quantum level. By systematically connecting the microscopic and macroscopic formulations of the entropy production rate in terms of appropriate entropic biases and entropic fluxes, our analysis identifies the conditions under which a \textit{genuine} ICC effect can arise in quantum thermal transport and highlights potential applications in autonomous quantum engines and refrigerators.

2404.15142 2026-03-27 math.MG

Face embeddings of Archimedean solids

Tommy Murphy, David Weed

Comments v2: to appear in BZAG. Packing results removed to appear in a subsequent work

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We characterize the Archimedean solids among the convex uniform polyhedra via face embeddings into a regular Tetrahedron. This result has been listed without proof in the literature.

2404.11786 2026-03-27 math.OC

A Sequential Benders-based Mixed-Integer Quadratic Programming Algorithm and Its Implementation in the CAMINO Toolbox

Andrea Ghezzi, Wim Van Roy, Sebastian Sager, Moritz Diehl

Comments Andrea Ghezzi and Wim Van Roy contributed equally to this work. 56 pages, 15 figures, 8 tables

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Sequential quadratic programming and sequential convex programming efficiently solve nonlinear programs (NLPs) by linearizing inner nonlinearities while preserving the outer convex structure. This paper introduces a sequential mixed-integer quadratic programming (MIQP) algorithm to extend this methodology to mixed-integer nonlinear problems (MINLPs), leveraging the efficiency of modern MIQP solvers. The algorithm uses a three-step iterative process. First, the MINLP is linearized around the current iterate. Second, an MIQP is formulated and solved, with its feasible region restricted to a specific area around the linearization point. This region is defined using objective values and derivatives from previous iterations, drawing on concepts from generalized Benders' decomposition. Third, the integer variables from the MIQP solution are fixed, and an NLP involving only the continuous variables is solved. The best solution among all iterates becomes the linearization point for the next iteration. A fallback strategy based on a mixed-integer linear program (MILP) is used when MIQP progress stalls. This guarantees convergence to the global optimal solution for convex MINLPs. For nonconvex problems, the algorithm functions as a heuristic without global optimality guarantees. Numerical experiments show its competitiveness with other MINLP solvers on benchmark problems. In addition, the algorithm was successfully applied to mixed-integer optimal control problems, demonstrating its effectiveness in handling challenging nonlinear equality constraints. The proposed algorithm is publicly available at https://github.com/minlp-toolbox/CAMINO with the name s-b-miqp.

2404.09297 2026-03-27 econ.GN q-fin.EC

Belief Bias Identification

Pedro Gonzalez-Fernandez

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This paper proposes a unified theoretical model to identify and test a comprehensive set of probabilistic updating biases within a single framework. The model achieves separate identification by focusing on the updating of belief distributions, rather than point beliefs alone. Estimating the model in a laboratory experiment reveals significant individual heterogeneity: all tested biases are present and exhibit systematic co-occurrence patterns across individuals, with motivated-belief biases (optimism and pessimism) and sequence-related biases (gambler's and hot-hand fallacy) emerging as key drivers of biased inference. At the population level most biases average out, but base-rate neglect remains a persistent influence. This study contributes to the belief-updating literature by providing a methodological toolkit for researchers examining links between conflicting biases and connections between updating biases and other behavioral phenomena.

2403.18141 2026-03-27 math-ph math.CO math.MP math.PR

The 2D Toda lattice hierarchy for multiplicative statistics of Schur measures

Pierre Lazag

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We prove Fredholm determinants build out from generalizations of Schur measures, or equivalently, arbitrary multiplicative statistics of the original Schur measures are tau-functions of the 2D Toda lattice hierarchy. Our result apply to finite temperature Schur measures, and extends both the result of Okounkov in \cite{okounkovschurmeasures} and of Cafasso-Ruzza in \cite{cafassoruzza} concerning the finite-temperature Plancherel measure. Our proof lies on the semi-infinite wedge formalism and the Boson-Fermion correspondance.

2403.10282 2026-03-27 math.NA cs.NA math.OC

Non-Conforming Structure Preserving Finite Element Method for Doubly Diffusive Flows on Bounded Lipschitz Domains

Jai Tushar, Arbaz Khan, Manil T. Mohan

Comments Revised manuscript

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We study a stationary model of doubly diffusive flows with temperature-dependent viscosity on bounded Lipschitz domains in two and three dimensions. A new well-posedness and regularity analysis of weak solutions under minimal assumptions on domain geometry and data regularity are established. A fully non-conforming finite element method based on Crouzeix-Raviart elements, which ensures locally exactly divergence-free velocity fields is explored. Unlike previously proposed schemes, this discretization enables to establish uniqueness of the discrete solutions. We prove the well-posedness of the discrete problem and derive a priori error estimates. An accuracy test is conducted to verify the theoretical error decay rates in flow, Stokes and Darcy regimes on convex and non-convex domains, and a benchmark test of flow in a porous cavity is conducted, comparing the proposed method with existing literature.

2401.06240 2026-03-27 quant-ph cs.DS cs.NA math.NA physics.chem-ph

Quantum eigenvalue processing

Guang Hao Low, Yuan Su

Comments 114 pages, 3 figures. Tabulated common measures of non-normality (Jordan condition number, numerical range, pseudospectrum) and the corresponding cost of eigenvalue processors. Improved complexity of initial state preparation using the block preconditioning technique from arXiv:2410.18178. Enhanced version of the paper presented at FOCS 2024 and published in SICOMP

Journal ref SIAM Journal on Computing 55 (2026), no. 1, 135-215

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Many problems in linear algebra -- such as those arising from non-Hermitian physics and differential equations -- can be solved on a quantum computer by processing eigenvalues of the non-normal input matrices. However, the existing Quantum Singular Value Transformation (QSVT) framework is ill-suited for this task, as eigenvalues and singular values are different in general. We present a Quantum EigenValue Transformation (QEVT) framework for applying arbitrary polynomial transformations on eigenvalues of block-encoded non-normal operators, and a related Quantum EigenValue Estimation (QEVE) algorithm for operators with real spectra. QEVT has query complexity to the block encoding nearly recovering that of the QSVT for a Hermitian input, and QEVE achieves the Heisenberg-limited scaling for diagonalizable input matrices. As applications, we develop a linear differential equation solver with strictly linear time query complexity for average-case diagonalizable operators, as well as a ground state preparation algorithm that upgrades previous nearly optimal results for Hermitian Hamiltonians to diagonalizable matrices with real spectra. Underpinning our algorithms is an efficient method to prepare a quantum superposition of Faber polynomials, which generalize the nearly-best uniform approximation properties of Chebyshev polynomials to the complex plane. Of independent interest, we also develop techniques to generate $n$ Fourier coefficients with $\mathbf{O}(\mathrm{polylog}(n))$ gates compared to prior approaches with linear cost.

2312.03083 2026-03-27 quant-ph

Dual-VQE: A quantum algorithm to lower bound the ground-state energy

Hanna Westerheim, Jingxuan Chen, Zoë Holmes, Ivy Luo, Theshani Nuradha, Dhrumil Patel, Soorya Rethinasamy, Kathie Wang, Mark M. Wilde

Comments v3: 15 pages, 8 figures, accepted for publication in Physical Review A

Journal ref Physical Review A, vol. 113, no. 3, page 032443, March 2026

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The variational quantum eigensolver (VQE) is a hybrid quantum-classical variational algorithm that produces an upper-bound estimate of the ground-state energy of a Hamiltonian. As quantum computers become more powerful and go beyond the reach of classical brute-force simulation, it is important to assess the quality of solutions produced by them. Here we propose a dual variational quantum eigensolver (dual-VQE) that produces a lower-bound estimate of the ground-state energy. As such, VQE and dual-VQE can serve as quality checks on their solutions; in the ideal case, the VQE upper bound and the dual-VQE lower bound form an interval containing the true optimal value of the ground-state energy. The idea behind dual-VQE is to employ semidefinite programming duality to rewrite the ground-state optimization problem as a constrained maximization problem, which itself can be bounded from below by an unconstrained optimization problem to be solved by a variational quantum algorithm. When using a convex combination ansatz in conjunction with a classical generative model, the quantum computational resources needed to evaluate the objective function of dual-VQE are no greater than those needed for that of VQE. We also show that the problem is well suited for classical pretraining using matrix product states and these methods help warm-start the optimization. We simulated the performance of dual-VQE on the transverse-field Ising model with and without pretraining and found that, for the example considered, while dual-VQE training is slower and noisier than VQE, it approaches the true value with an error of order $10^{-2}$.

2311.15403 2026-03-27 hep-th math-ph math.MP

Mirror symmetry and new approach to constructing orbifolds of Gepner models

Alexander Belavin, Sergey Parkhomenko

Journal ref Nucl.Phys. B998 (2024) 116431

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Motivated by the principles of the conformal bootstrap, primarily the principle of Locality, simultaneously with the requirement of space-time supersymmetry, we reconsider constructions of compactified superstring models. Starting from requirements of space-time supersymmetry and mutual locality, we construct a complete set of physical fields of orbifolds of Gepner models. To technically implement this, we use spectral flow generators to construct all physical fields from the chiral primary fields. The set of these spectral flow operators forms a so-called admissible group $G_{adm}$, which defines a given orbifold. The action of these operators produces a collection of physical fields consistent with the action of supersymmetry generators. The selection of mutually local fields from this collection is carried out using the mirror group $G^*_{adm}$. The permutation of $G_{adm}$ and $G^*_{adm}$ replaces the original orbifold with a mirror one that satisfies the same conditions as the original one. This also implies that the resulting model is modular invariant.

2309.16580 2026-03-27 math.AG

On the superadditivity of anticanonical Iitaka dimension

Marta Benozzo, Iacopo Brivio, Chi-Kang Chang

Comments 39 pages. (v4) minor corrections. Final version to appear in Advances in Mathematics

Journal ref Adv. Math. 491, Article ID 110860, 50 p. (2026)

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Given a fibration $f: X \to Y$ with normal general fibre $X_y$, over a field of any characteristic, we establish the Iitaka-type inequality $κ(X,-K_X) \leq κ(X_y,-K_{X_y})+κ(Y,-K_Y)$ whenever the $\mathbb{Q}$-linear series $|-K_X|_{\mathbb{Q}}$ has good singularities on $X_y$.

2309.08432 2026-03-27 math.AG math.RT

Topological K-theory of quasi-BPS categories of symmetric quivers with potential

Tudor Pădurariu, Yukinobu Toda

Comments 91 pages, improvements in Sections 4-6, added Appendix A

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In previous works, we introduced and studied certain categories called quasi-BPS categories associated to symmetric quivers with potential, preprojective algebras, and local surfaces. They have properties reminiscent of BPS invariants/ cohomologies in enumerative geometry, for example they play important roles in categorical wall-crossing formulas. In this paper, we make the connections between quasi-BPS categories and BPS cohomologies more precise via the cycle map for topological K-theory. We show the existence of filtrations on topological K-theory of quasi-BPS categories whose associated graded are isomorphic to the monodromy invariant BPS cohomologies. Along the way, we also compute the topological K-theory of categories of matrix factorizations in terms of the monodromy invariant vanishing cycles (a version of this comparison was already known by work of Blanc-Robalo-Toën-Vezzosi), prove a Grothendieck-Riemann-Roch theorem for matrix factorizations, and prove the compatibility between the Koszul equivalence in K-theory and dimensional reduction in cohomology. In a separate paper, we use the results from this paper to show that the quasi-BPS categories of K3 surfaces recover the BPS invariants of the corresponding local surface, which are Euler characteristics of Hilbert schemes of points on K3 surfaces.

2308.05824 2026-03-27 math.DS

Topology of global attractors for homeomorphisms with the topological shadowing property in $\mathbb{R}^m$

Gonzalo Cousillas, Jorge Groisman

Comments 11 pages, 1 figure

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This paper studies the behavior of dynamical systems in non-compact spaces, specifically focusing on the concepts of global attractors and shadowing. Let $K$ be a compact global attractor. We show that the shadowing property holds in certain types of dynamical systems in non-compact spaces if and only if $K$ is trivial.

2307.01941 2026-03-27 math.AG math.AT math.SG

A relative orientation for the moduli space of stable maps to a del Pezzo surface

Jesse Leo Kass, Marc Levine, Jake P. Solomon, Kirsten Wickelgren

Comments 81 pages. Accepted for publication in Algebraic Geometry

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We prove orientation results for evaluation maps of moduli spaces of rational stable maps to del Pezzo surfaces over a field, both in characteristic $0$ and in positive characteristic. These results and the theory of degree developed in a sequel produce quadratically enriched counts of rational curves over non-algebraically closed fields of characteristic not $2$ or $3$. Orientations are constructed in two steps. First, the ramification locus of the evaluation map is shown to be the divisor in the moduli space of stable maps where image curves have a cusp. Second, this divisor is related to the discriminant of a branched cover of the moduli space given generically by pairs of points on the universal curve with the same image.

2305.19823 2026-03-27 quant-ph physics.optics

Optoacoustic cooling of traveling hypersound waves

Laura Blázquez Martínez, Philipp Wiedemann, Changlong Zhu, Andreas Geilen, Birgit Stiller

Comments 5 pages, 3 figures, L. B. M., P. W. and C. Z. contributed equally to this work

Journal ref Phys. Rev. Lett. 132, 023603 (2024)

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We experimentally demonstrate optoacoustic cooling via stimulated Brillouin-Mandelstam scattering in a 50 cm-long tapered photonic crystal fiber. For a 7.38 GHz acoustic mode, a cooling rate of 219 K from room temperature has been achieved. As anti-Stokes and Stokes Brillouin processes naturally break the symmetry of phonon cooling and heating, resolved sideband schemes are not necessary. The experiments pave the way to explore the classical to quantum transition for macroscopic objects and could enable new quantum technologies in terms of storage and repeater schemes.

2305.16461 2026-03-27 math.DG math.CV

Singularities of the Chern-Ricci flow

Quang-Tuan Dang

Comments final version, to appear in Analysis & PDE

Journal ref https://msp.org/apde/2026/19-3/p02.xhtml

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We study the nature of finite-time singularities for the Chern-Ricci flow, partially answering a question of Tosatti-Weinkove. We show that a solution of degenerate parabolic complex Monge-Ampère equations starting from arbitrarily positive (1,1)-currents are smooth outside some analytic subset, generalizing works by Di Nezza-Lu. We extend Guedj-Lu's recent approach to establish uniform a priori estimates for degenerate complex Monge-Ampère equations on compact Hermitian manifolds. We apply it to studying the Chern-Ricci flows on complex log terminal varieties starting from an arbitrary current.

2305.08205 2026-03-27 math.PR math-ph math.MP

More scaling limits for 1d random Schrödinger operators with critically decaying and vanishing potentials

Yi Han

Comments 22 pages

Journal ref Lett Math Phys 116, 41 (2026)

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Consider the random Schrödinger operator $H_n$ defined on $\{0,1,\cdots,n\}\subset\mathbb{Z}$ $$ (H_nψ)_\ell=ψ_{\ell-1,n}+ψ_{\ell+1,n}+σ\frac{ω_\ell}{a_{\ell,n}}ψ_{\ell,n},\quad ψ_0=ψ_{n+1}=0, $$ where $σ>0$, $ω_\ell$ are i.i.d. random variables and $a_{\ell,n}$ typically has order $\sqrt{n}$ for $\ell\in[εn,(1-ε)n]$ and any $ε>0$. Two important cases: (a) the vanishing case $a_{\ell,n}=\sqrt{n}$ and (b) the decaying case $a_{\ell,n}=\sqrt{\ell}$, were studied before in \cite{kritchevski2011scaling}. In this paper we consider more general decaying profiles that lie in between these two extreme cases. We characterize the scaling limit of transfer matrices and determine the point process limit of eigenvalues near a fixed energy in the bulk, in terms of solutions to coupled SDEs. We obtain new point processes that share similar properties to the $\text{Sch}_τ$ process. We determine the shape profile of eigenfunctions after a suitable rescaling, that corresponds to a uniformly chosen eigenvalue of $H_n$. We also give a more detailed description of the newly defined point processes, including the probability of small and large gaps and a variance estimate.

2304.02678 2026-03-27 math.SP math.GT

Friedman-Ramanujan functions in random hyperbolic geometry and application to spectral gaps I

Nalini Anantharaman, Laura Monk

Comments 71 pages, 18 figures. This new version is shorter due to making the former last section into a standalone article (to appear on arxiv). Content is otherwise unchanged

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In this series of articles, we analyse the level-sets of length functions on the moduli space of compact hyperbolic surfaces of fixed genus. This work ultimately culminates in a proof that typical hyperbolic surfaces have an optimal spectral gap. In this first article, we introduce new volume functions $V_g^T(l)$, counting the expected number of closed geodesics of type $T$ and length $l$ on a random hyperbolic surface of genus $g$. So far, this function has only been considered in the case where the type is simple, in which case it can be expressed as a combination of Weil-Petersson volumes polynomials, as proven by Mirzakhani. We provide an integral expression for $V_g^T(l)$ for any prescribed type $T$, which we use to prove that $V_g^T(l)$ admits a full asymptotic expansion in powers of $1/g$. We then claim that the coefficients in this expansion, as a function of the length variable $l$, belong to a newly-introduced class of functions called "Friedman-Ramanujan functions". We relate this claim to the study of the spectral gap of the Laplace-Beltrami operator, and prove it when $T$ fills a surface of Euler characteristic $0$ or $-1$, providing a method to explicitly compute all coefficients in the second-order expansion. We conclude by displaying how the presence of tangles (which is an event of vanishing probability) prevents the sum over all types to satisfy the Friedman-Ramanujan property at the second order.

2303.16075 2026-03-27 math.RT math.AG math.AT

Harder-Narasimhan Filtrations of Persistence Modules

Marc Fersztand, Emile Jacquard, Vidit Nanda, Ulrike Tillmann

Comments 28 pages, comments welcome!

Journal ref Transactions of the London Mathematical Society, 11(1), e70003 (2024)

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The Harder-Narasimhan type of a quiver representation is a discrete invariant parameterised by a real-valued function (called a central charge) defined on the vertices of the quiver. In this paper, we investigate the strength and limitations of Harder-Narasimhan types for several families of quiver representations which arise in the study of persistence modules. We introduce the skyscraper invariant, which amalgamates the HN types along central charges supported at single vertices, and generalise the rank invariant from multiparameter persistence modules to arbitrary quiver representations. Our four main results are as follows: (1) we show that the skyscraper invariant is strictly finer than the rank invariant in full generality, (2) we characterise the set of complete central charges for zigzag (and hence, ordinary) persistence modules, (3) we extend the preceding characterisation to rectangle-decomposable multiparameter persistence modules of arbitrary dimension; and finally, (4) we show that although no single central charge is complete for nestfree ladder persistence modules, a finite set of central charges is complete.

2303.14805 2026-03-27 hep-ph

Sensitivity of anomalous quartic gauge couplings via tri-photon production at FCC-hh

A. Senol, H. Denizli, C. Helveci

Comments 17 pages, 6 figures, In the published version of this paper, there is a typographical error in Equation (9) (the closing square bracket is misplaced). This has been corrected in the version

Journal ref Nucl.Phys.B 998 (2024) 116387

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英文摘要

A direct investigation of the self-couplings of gauge bosons, completely described by the non-Abelian gauge symmetry of the Standard Model, is extremely valuable in understanding the gauge structure of the SM. Any deviation from the SM predictions on gauge boson self-coupling is to give a hint at the existence of a new physics beyond the SM, which is defined with a modification of the self-interactions using an effective field theory approach. In this paper, we present a detailed Monte Carlo study searching for anomalous quartic gauge dimension-8 couplings related to $γγγγ$ and $γγγZ$ vertices at the future hadron-hadron collider (FCC-hh) via tri-photon production at a 100 TeV center of mass energy with an integrated luminosity L$_{int}$=30 ab$^{-1}$. Events that have been parton showered and include detector effects are analyzed with a Toolkit for Multivariate Data Analysis (TMVA) using a boosted decision tree to help distinguish between signal and background events to achieve the best sensitivities on anomalous quartic gauge couplings. Our obtained results reveal that the limits on anomalous quartic gauge couplings $f_{T8}/Λ^{4}$ and $f_{T9}/Λ^{4}$ at 95\% C.L. without systematic errors are about three orders of magnitude stronger compared to the best current experimental limits reported by the ATLAS collaboration at the LHC. Considering a realistic systematic uncertainty such as 10\% from possible experimental sources, our obtained limits of anomalous quartic couplings get worse by about one order of magnitude compared to those without systematic uncertainty but are still two orders of magnitude better than those recently reported by ATLAS.