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In this contribution, we introduce a general class of car-following models with an input-state-output port-Hamiltonian structure. We derive stability conditions and long-term behavior of the finite system with periodic boundaries and…

Dynamical Systems · Mathematics 2025-02-04 Julia Ackermann , Matthias Ehrhardt , Thomas Kruse , Antoine Tordeux

We introduce a quantum extension of dynamic programming, a fundamental computational method that efficiently solves recursive problems using memory. Our innovation lies in showing how to coherently generate recursion step unitaries by using…

Quantum Physics · Physics 2025-05-09 Jeongrak Son , Marek Gluza , Ryuji Takagi , Nelly H. Y. Ng

We present a simple theory accounting for two central observations in a recent experiment on quantum coarsening and collective dynamics on a programmable quantum simulator [T. Manovitz et al., Nature \textbf{638}, 86 (2025)]: an apparent…

Statistical Mechanics · Physics 2026-03-02 Federico Balducci , Anushya Chandran , Roderich Moessner

We study the distribution of quantum steerability for continuous variables between two causally disconnected open charts in de Sitter space. It is shown that quantum steerability suffers from "sudden death" in de Sitter space, which is…

General Relativity and Quantum Cosmology · Physics 2020-02-05 Cuihong Wen , Jieci Wang , Jiliang Jing

The phenomenon of PT (parity- and time-reversal) symmetry breaking is conventionally associated with a change in the complex mode spectrum of a non-Hermitian system that marks a transition from a purely oscillatory to an exponentially…

The description of spontaneous symmetry breaking that underlies the connection between classically ordered objects in the thermodynamic limit and their individual quantum mechanical building blocks is one of the cornerstones of modern…

Other Condensed Matter · Physics 2010-04-29 Jasper van Wezel

A quantum measuring instrument is constructed that utilises symmetry breaking to enhance a microscopic signal. The entire quantum system consists of a system-apparatus-environment triad that is composed of a small set of spin-1/2 particles.…

Quantum Physics · Physics 2018-08-07 H. C. Donker , H. De Raedt , M. I. Katsnelson

In this article we study the quench dynamics of Galilean and scale invariant many-body systems which can be prepared using interacting atomic gases. The far-away from equilibrium dynamics are investigated by employing $m$-body density…

Quantum Gases · Physics 2019-08-07 Jeff Maki , Fei Zhou

We consider an arbitrary quantum system coupled non perturbatively to a large arbitrary and fully quantum environment. In [G. Ithier and F. Benaych-Georges, Phys. Rev. A 96, 012108 (2017)] the typicality of the dynamics of such an embedded…

Quantum Physics · Physics 2017-12-20 Grégoire Ithier , Saeed Ascroft , Florent Benaych-Georges

Unitary designs are unitary ensembles that emulate Haar-random unitary statistics. They provide a vital tool for studying quantum randomness and have found broad applications in quantum technologies. However, existing research has focused…

Quantum Physics · Physics 2026-01-06 Xiaodong Yang , Jiaqing Leng , Jun Li

The execution of quantum circuits on real systems has largely been limited to those which are simply time-ordered sequences of unitary operations followed by a projective measurement. As hardware platforms for quantum computing continue to…

Quantum state tomography is a core task in quantum system identification. Real experimental conditions often deviate from nominal designs, introducing errors in both the measurement devices and the Hamiltonian governing the system's…

Quantum Physics · Physics 2025-12-16 Alan Chen , Shuixin Xiao , Hailan Ma , Daoyi Dong

We study the dynamics of quantum statistical ensembles at first-order phase transition points of finite macroscopic systems. First, we show that at the first-order phase transition point of systems with an order parameter that does not…

Statistical Mechanics · Physics 2023-10-10 Yasushi Yoneta

A pair of coupled quantum harmonic oscillators, one subject to a gain one to a loss, is a paradigmatic setup to implement PT-symmetric, non-Hermitian Hamiltonians in that one such Hamiltonian governs the mean-field dynamics for equal gain…

Quantum Physics · Physics 2019-07-03 Federico Roccati , Salvatore Lorenzo , G. Massimo Palma , Francesco Ciccarello

Long-range entangled states are vital for quantum information processing and quantum metrology. Preparing such states by combining measurements with unitary gates opened new possibilities for efficient protocols with finite-depth quantum…

Quantum Physics · Physics 2024-08-07 Iosifina Angelidi , Marcin Szyniszewski , Arijeet Pal

We design several examples of constrained, symmetric quantum circuit dynamics that generate non-equilibrium steady states. The qubit networks maintain local memory of the initial conditions and display inhomogeneous subsystem dynamics over…

Quantum Physics · Physics 2025-05-02 Unnati Akhouri , Sarah Shandera , Jackson Henry

We analyze the response of a complex quantum-mechanical system (e. g., a quantum dot) to a time-dependent perturbation. Assuming the dot energy spectrum and the perturbation to be described by the Gaussian Orthogonal Ensemble of random…

Mesoscale and Nanoscale Physics · Physics 2009-11-07 D. M. Basko , M. A. Skvortsov , V. E. Kravtsov

It is now widely accepted that quenches through the critical region of quantum phase transitions result in post-transition states populated with topological defects -- analogs of the classical topological defects. However, consequences of…

Quantum Physics · Physics 2022-12-29 Jacek Dziarmaga , Marek M. Rams , Wojciech H. Zurek

We outline a program with the potential to solve both the cosmological constant and quantum gravity problems within a single, comprehensive framework, one that is formulated entirely in four spacetime dimensions. The program is based on an…

High Energy Physics - Theory · Physics 2008-10-06 Philip D. Mannheim

We prove stability of the spectral gap for gapped, frustration-free Hamiltonians under general, quasi-local perturbations. We present a necessary and sufficient condition for stability, which we call "Local Topological Quantum Order" and…

Quantum Physics · Physics 2013-07-22 Spyridon Michalakis , Justyna Pytel