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We introduce a method that ensures efficient computation of one-dimensional quantum systems with long-range interactions across all temperatures. Our algorithm operates within a quasi-polynomial runtime for inverse temperatures up to…

Quantum Physics · Physics 2025-05-19 Rakesh Achutha , Donghoon Kim , Yusuke Kimura , Tomotaka Kuwahara

We consider a quantum quench in a non-interacting fermionic one-dimensional field-theory. The system of size $L$ is initially prepared into two halves $\mathcal{L}$ ($[-L/2,0]$) and $\mathcal{R}$ ($[0,L/2]$), each of them thermalized at two…

Statistical Mechanics · Physics 2014-10-23 Mario Collura , Dragi Karevski

When we consider canonical average for classical discrete systems under constant composition (specifically, substitutional alloys) as a map phi from a set of many-body interatomic interactions to that of microscopic configuration in…

Statistical Mechanics · Physics 2025-05-12 Ryu Tomitaka , Koretaka Yuge

Predicting the stationary behavior of observables in isolated many-body quantum systems is a central challenge in quantum statistical mechanics. While one can often use the Gibbs ensemble, which is simple to compute, there are many…

Quantum Physics · Physics 2025-07-30 Lodovico Scarpa , Abdulla Alhajri , Vlatko Vedral , Fabio Anza

In this article we introduce a novel quantum state, the perfect quantum optical vortex state which exhibits a highly localised distribution along a ring in the quadrature space. We examine its nonclassical properties using the Wigner…

Quantum Physics · Physics 2016-11-30 Anindya Banerji , Ravindra Pratap Singh , Dhruba Banerjee , Abir Bandyopadhyay

We derive the steady state solution of the Fokker-Planck equation that describes the dynamics of the nondegenerate optical parametric oscillator in the truncated Wigner representation of the density operator. We assume that the pump mode is…

Quantum Physics · Physics 2011-12-24 K. Dechoum , M. D. Hahn , R. O. Vallejos , A. Z. Khoury

Entanglement is the hallmark of quantum physics, yet its characterization in interacting many-body systems at thermal equilibrium remains one of the most important challenges in quantum statistical physics. We prove that the Gibbs state of…

Quantum Physics · Physics 2026-02-17 Ainesh Bakshi , Soonwon Choi , Saúl Pilatowsky-Cameo

The preparation of Gibbs thermal states is an important task in quantum computation with applications in quantum simulation, quantum optimization, and quantum machine learning. However, many algorithms for preparing Gibbs states rely on…

Quantum Physics · Physics 2022-03-25 Ada Warren , Linghua Zhu , Nicholas J. Mayhall , Edwin Barnes , Sophia E. Economou

After a sudden disruption, weakly interacting quantum systems first relax to a prethermalized state that can be described by perturbation theory and a generalized Gibbs ensemble. Using these properties of the prethermalized state we…

Strongly Correlated Electrons · Physics 2013-08-27 Michael Stark , Marcus Kollar

Both classical and quantum damped systems give rise to complex spectra and corresponding resonant states. We investigate how resonant states, which do not belong to the Hilbert space, fit the phase space formulation of quantum mechanics. It…

Mathematical Physics · Physics 2007-05-23 D. Chruscinski

Efficient representation of quantum many-body states on classical computers is a problem of enormous practical interest. An ideal representation of a quantum state combines a succinct characterization informed by the system's structure and…

Quantum Physics · Physics 2023-04-11 Abhijith Jayakumar , Marc Vuffray , Andrey Y. Lokhov

We present a Gutzwiller von Neumann dynamics (GvND) method for simulating equilibrium and nonequilibrium phenomena in strongly correlated electron systems. Our approach is a real-space formulation of the time-dependent Gutzwiller…

Strongly Correlated Electrons · Physics 2017-11-22 Gia-Wei Chern

We formulate a canonical quantization of Equilibrium Thermodynamics by applying Dirac's theory of constrained systems. Thermodynamic variables are treated as conjugate pairs of coordinates and momenta, allowing extensive and intensive…

Quantum Physics · Physics 2025-11-19 Luis F. Santos , Victor Hugo M. Ramos , Danilo Cius , Mario C. Baldiotti , Bárbara Amaral

The local physical properties of an isolated quantum statistical system in the stationary state reached long after a quench are generically described by the Gibbs ensemble, which involves only its Hamiltonian and the temperature as a…

Statistical Mechanics · Physics 2017-06-13 Laura Foini , Andrea Gambassi , Robert Konik , Leticia F. Cugliandolo

Simulating real-time dynamics of gauge theories represents a paradigmatic use case to test the hardware capabilities of a quantum computer, since it can involve non-trivial input states preparation, discretized time evolution, long-distance…

We derive the exact out-of-equilibrium Wigner function of a bosonic mode linearly coupled to a bosonic bath of arbitrary spectral density. Our solution does not rely on any master equation approach and it therefore also correctly describes…

Quantum Physics · Physics 2014-01-13 A. Rancon , J. Bonart

I investigate the extent to which the description of quantum systems by Gibbs states can be justified purely on the basis of tomographic data, without recourse to theoretical concepts such as infinite ensembles, environments, information,…

Quantum Physics · Physics 2014-12-22 Jochen Rau

Complex numbers appear in the Hilbert space formulation of quantum mechanics, but not in the formulation in phase space. Quantum symmetries are described by complex, unitary or antiunitary operators defining ray representations in Hilbert…

Quantum Physics · Physics 2009-11-11 A. J. Bracken

We consider a quantum mechanical system represented in phase space (referred to hereafter as "Wigner space"), coupled to a harmonic oscillator bath. We derive quantum hierarchal Fokker-Planck (QHFP) equations not only in real time, but also…

Statistical Mechanics · Physics 2015-04-16 Yoshitaka Tanimura

Realising high fidelity entangled states in controlled quantum many-body systems is challenging due to experimental uncertainty in a large number of physical quantities. We develop a robust optimal control method for achieving this goal in…

Quantum Physics · Physics 2021-10-26 Nguyen H. Le , Max Cykiert , Eran Ginossar