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We study the problem of learning a local quantum Hamiltonian $H$ given copies of its Gibbs state $\rho = e^{-\beta H}/\textrm{tr}(e^{-\beta H})$ at a known inverse temperature $\beta>0$. Anshu, Arunachalam, Kuwahara, and Soleimanifar…

Quantum Physics · Physics 2026-05-11 Ainesh Bakshi , Allen Liu , Ankur Moitra , Ewin Tang

We identify the low energy effective Hamiltonian that is expected to describe the low temperature properties of the frustrated magnet $\mathrm{Ca}_{10}\mathrm{Cr}_{7}\mathrm{O}_{28}$. Motivated by the fact that this effective Hamiltonian…

Strongly Correlated Electrons · Physics 2018-03-07 Sounak Biswas , Kedar Damle

We consider a perturbed Floquet Hamiltonian $-i\partial_t + H + \beta V(\omega t)$ in the Hilbert space $L^2([0,T],E,dt)$. Here $H$ is a self-adjoint operator in $E$ with a discrete spectrum obeying a growing gap condition, $V(t)$ is a…

Mathematical Physics · Physics 2008-11-06 P. Duclos , P. Stovicek , M. Vittot

Understanding the emergence of chaos in many-body quantum systems away from semi-classical limits, particularly in spatially local interacting spin Hamiltonians, has been a long-standing problem. In these intrinsically quantum regimes,…

Statistical Mechanics · Physics 2025-01-24 Christopher M. Langlett , Cheryne Jonay , Vedika Khemani , Joaquin F. Rodriguez-Nieva

Based on an attractive $U$ Hubbard model on a lattice with up to second neighbor hopping we derive an effective Hamiltonian for phase fluctuations. The superconducting gap is assumed to have s-wave symmetry. The effective Hamiltonian we…

Superconductivity · Physics 2009-11-10 Wonkee Kim , J. P. Carbotte

In this paper we present a new mathematical rigorous technique for computing the average free energy of a disordered system with quenched randomness, using the replicas. The basic tool of this technique is a distributional zeta-function, a…

Statistical Mechanics · Physics 2016-09-21 B. F. Svaiter , N. F. Svaiter

The Hamiltonian Mean Field (HMF) model has a low-energy phase where $N$ particles are trapped inside a cluster. Here, we investigate some properties of the trapping/untrapping mechanism of a single particle into/outside the cluster. Since…

Chaotic Dynamics · Physics 2007-11-25 Hiroko Koyama , Tetsuro Konishi , Stefano Ruffo

A conceptually simple physical interpretation of a conserved Hamiltonian $\mathcal{H}$ for a mechanical system with a time-dependent constraint is given. For the case of a bead on a vertical hoop forced to rotate with constant angular…

Classical Physics · Physics 2019-05-22 Víctor F. Correa

We investigate relations between spectral properties of a single-centre point-interaction Hamiltonian describing a particle confined to a bounded domain $\Omega\subset\mathbb{R}^{d},\: d=2,3$, with Dirichlet boundary, and the geometry of…

Mathematical Physics · Physics 2019-12-10 Pavel Exner , Andrea Mantile

This paper concerns a first-order algorithmic technique for a class of optimal control problems defined on switched-mode hybrid systems. The salient feature of the algorithm is that it avoids the computation of Fr\'echet or G\^ateaux…

Optimization and Control · Mathematics 2016-09-13 Yorai Wardi , Magnus Egerstedt , Muhammad Umer Qureshi

We show that superconductors with inhomogeneous order parameters can show similar features as anisotropic ones. In this paper we study the low temperature specific heat dependence in such a system and we show that the disorder associated…

Superconductivity · Physics 2015-06-24 Grzegorz Litak

The thermal self-energy of an electron in a static uniform magnetic field $B$ is calculated to first order in the fine structure constant $\alpha $ and to all orders in $eB$. We use two methods, one based on the Furry picture and another…

High Energy Physics - Phenomenology · Physics 2009-10-28 Per Elmfors , David Persson , Bo-Sture Skagerstam

We propose a method of quantization based on Hamilton-Jacobi theory in the presence of a random constraint due to the fluctuations of a set of hidden random variables. Given a Lagrangian, it reproduces the results of canonical quantization…

Quantum Physics · Physics 2012-07-05 Agung Budiyono

It is shown that a relevant control of Hamiltonian chaos is possible through suitable small perturbations whose form can be explicitly computed. In particular, it is possible to control (reduce) the chaotic diffusion in the phase space of a…

The influence of substitutional disorder on the transport properties of heavy-fermion systems is investigated. We extend the dynamical mean-field theory treatment of the periodic Anderson model (PAM) to a coherent-potential approximation…

Strongly Correlated Electrons · Physics 2008-03-25 Claas Grenzebach , Frithjof B. Anders , Gerd Czycholl , Thomas Pruschke

The behavior of electronic states of one dimensional correlated disordered systems which are modelled by a tight binding Hamiltonian is studied analytically using the invariant measure method. The approach of Bovier is generalized to…

Condensed Matter · Physics 2009-10-28 K. Kundu , D. Giri , K. Ray

We study theoretically the influence of the temperature and disorder on the spin wave spectrum of the magnonic crystal Fe$_{1-c}$Co$_{c}$. Our formalism is based on the analysis of a Heisenberg Hamiltonian by means of the wave vector and…

Materials Science · Physics 2023-01-06 Sebastian Paischer , Paweł A. Buczek , Nadine Buczek , David Eilmsteiner , Arthur Ernst

In this paper we study homogenization for a class of monotone systems of first-order time-dependent periodic Hamilton-Jacobi equations. We characterize the Hamiltonians of the limit problem by appropriate cell problems. Hence we show the…

Analysis of PDEs · Mathematics 2010-02-10 Fabio Camilli , Olivier Ley , Paola Loreti

The numerical approximation of an inverse problem subject to the convection--diffusion equation when diffusion dominates is studied. We derive Carleman estimates that are on a form suitable for use in numerical analysis and with explicit…

Numerical Analysis · Mathematics 2020-06-25 Erik Burman , Mihai Nechita , Lauri Oksanen

In a recent paper [P. Strasberg and M. Esposito, Phys. Rev. E {\bf 101}, 050101(R) (2020)] an attempt is presented to formulate the nonequilibrium thermodynamics of an open system in terms of the Hamiltonian of mean force. The purpose of…

Statistical Mechanics · Physics 2021-01-04 Peter Talkner , Peter Hänggi