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Open quantum systems are traditionally described by decomposing the total Hilbert space into a system and an external environment, linked by an explicit interaction Hamiltonian. We propose an alternative framework in which the environment…

Quantum Physics · Physics 2026-04-01 Yu Su , Yao Wang

We evaluate the entanglement entropy of a single connected region in excited states of one-dimensional massive free theories with finite numbers of particles, in the limit of large volume and region length. For this purpose, we use…

High Energy Physics - Theory · Physics 2018-10-18 Olalla A. Castro-Alvaredo , Cecilia De Fazio , Benjamin Doyon , István M. Szécsényi

In the context of quantum resource theories (QRTs), free states are defined as those which can be obtained at no cost under a certain restricted set of conditions. However, when taking a free state from one QRT and evaluating it through the…

Quantum Physics · Physics 2026-02-11 Andrew E. Deneris , Paolo Braccia , Pablo Bermejo , N. L. Diaz , Antonio A. Mele , M. Cerezo

We explore further the suggestion to describe a pre- and post-selected system by a two-state, which is determined by two conditions. Starting with a formal definition of a two-state Hilbert space and basic operations, we systematically…

Quantum Physics · Physics 2009-10-28 B. Reznik , Y. Aharonov

Unitary Designs have become a vital tool for investigating pseudorandomness since they approximate the statistics of the uniform Haar ensemble. Despite their central role in quantum information, their relation to quantum chaotic evolution…

Quantum Physics · Physics 2025-02-19 Michele Fava , Jorge Kurchan , Silvia Pappalardi

We derive an exact expression for the quantumness of a Hilbert space (defined in quant-ph/0302092), and show that in composite Hilbert spaces the signal states must contain at least some entangled states in order to achieve such a…

Quantum Physics · Physics 2007-05-23 Christopher A. Fuchs

We investigate the quantization of a free particle coupled linearly to a harmonic oscillator. This system, whose classical counterpart has clearly separated regular and chaotic regions, provides an ideal framework for studying the…

Chaotic Dynamics · Physics 2009-11-13 Thomas Mainiero , Mason A. Porter

Common notions of entanglement are based on well-separated subsystems. However, obtaining such independent degrees of freedom is not always possible because of physical constraints. In this work, we explore the notion of entanglement in the…

Quantum Physics · Physics 2025-04-08 Franziska Barkhausen , Laura Ares Santos , Stefan Schumacher , Jan Sperling

We investigate the implications of free probability for random matrices. From rules for calculating all possible joint moments of two free random matrices, we develop a notion of partial freeness which is quantified by the breakdown of…

Probability · Mathematics 2013-05-23 Jiahao Chen , Troy Van Voorhis , Alan Edelman

We investigate recurrence phenomena in coupled two degrees of freedom systems. It is shown that an initial well localized wave packet displays recurrences even in the presence of coupling in these systems. We discuss the interdependence of…

Quantum Physics · Physics 2009-11-13 Farhan Saif

Most states in the Hilbert space are maximally entangled. This fact has proven useful to investigate - among other things - the foundations of statistical mechanics. Unfortunately, most states in the Hilbert space of a quantum many body…

Quantum Physics · Physics 2015-05-30 Alioscia Hamma , Siddhartha Santra , Paolo Zanardi

The study of multipartite entanglement is not only interesting but also important due to its wide application in quantum information processing. However, the complicated structure of the Hilbert space for many parties makes multipartite…

Mathematical Physics · Physics 2022-03-03 Songbo Xie

We show that almost every pure state of multi-party quantum systems (each of whose local Hilbert space has the same dimension) is completely determined by the state's reduced density matrices of a fraction of the parties; this fraction is…

Quantum Physics · Physics 2007-05-23 N. Linden , W. K. Wootters

Device-independent randomness generation and quantum key distribution protocols rely on a fundamental relation between the non-locality of quantum theory and its random character. This relation is usually expressed in terms of a trade-off…

Quantum Physics · Physics 2018-03-20 Olmo Nieto-Silleras , Cédric Bamps , Jonathan Silman , Stefano Pironio

Free variables occur frequently in mathematics and computer science with ad hoc and altering semantics. We present the most recent version of our free-variable framework for two-valued logics with properly improved functionality, but only…

Artificial Intelligence · Computer Science 2024-05-30 Claus-Peter Wirth

The restrictions that nature places on the distribution of correlations in a multipartite quantum system play fundamental roles in the evolution of such systems, and yield vital insights into the design of protocols for the quantum control…

Quantum Physics · Physics 2007-05-23 Tracey E. Tessier

Quantum coherences characterise the ability of particles to quantum mechanically interfere within some given distances. In the context of noisy many-body quantum systems these coherences can fluctuate. A simple toy model to study such…

Statistical Mechanics · Physics 2023-04-03 Ludwig Hruza , Denis Bernard

We propose a simple model of classical open system consisting of two subsystems all stationary states of which correspond to phase synchronization between the subsystems. The model is generalized to quantum systems in a finite-dimensional…

Quantum Physics · Physics 2015-03-17 E. D. Vol

Recent experimental and theoretical developments in many-body quantum systems motivate the study of their out-of-equilibrium properties through multi-time correlation functions. We consider the dynamics of higher-order out-of-time-order…

Quantum Physics · Physics 2025-06-24 Felix Fritzsch , Pieter W. Claeys

We present the entanglement properties of the spin-orbital coupling systems with multiple degrees of freedom. After constructing the maximally entangled spin-orbital basis of bipartite, we find that the quantum entanglement length in the…

Strongly Correlated Electrons · Physics 2007-05-23 Dong-Meng Chen , Wei-Hua Wang , Liang-Jian Zou