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We study the universal structure of late-time ensembles obtained from unitary dynamics in quantum chaotic systems with symmetries, such as charge or energy conservation. We find that although quantum states do not ergodically explore the…

Random matrix ensembles are introduced that respect the local tensor structure of Hamiltonians describing a chain of $n$ distinguishable spin-half particles with nearest-neighbour interactions. We prove a central limit theorem for the…

Mathematical Physics · Physics 2017-06-19 J. P. Keating , N. Linden , H. J. Wells

The quantum nature of a microscopic system can only be revealed when it is sufficiently decoupled from surroundings. Interactions with the environment induce relaxation and decoherence that turn the quantum state into a classical mixture.…

Mesoscale and Nanoscale Physics · Physics 2017-09-12 Alexey M. Shakirov , Alexey N. Rubtsov , Alexander I. Lichtenstein , Pedro Ribeiro

The information in quantum computers is often stored in identical two-level systems (spins or pseudo-spins) that are separated by a distance shorter than the characteristic wavelength of a reservoir which is responsible for decoherence. In…

Quantum Physics · Physics 2016-09-08 Shoko Utsunomiya , Cyrus P. Master , Yoshihisa Yamamoto

Studying the complexity of states sampled from various ensembles is a central component of quantum information theory. In this work we establish the average-case hardness of learning, in the statistical query model, the Born distributions…

Quantum Physics · Physics 2026-01-16 Maxwell West

We propose a method for detecting bipartite entanglement in a many-body mixed state based on estimating moments of the partially transposed density matrix. The estimates are obtained by performing local random measurements on the state,…

Quantification of coherence lies at the heart of quantum information processing and fundamental physics. Exact evaluation of coherence measures generally needs a full reconstruction of the density matrix, which becomes intractable for…

Quantum Physics · Physics 2021-06-28 Qi-Ming Ding , Xiao-Xu Fang , Xiao Yuan , Ting Zhang , He Lu

We illustrate through numerical results a number of features of environment-induced decoherence under a broad class of apparatus-environment interactions in quantum measurements wherein the reduced system-apparatus density matrix evolves…

Quantum Physics · Physics 2007-06-13 Avijit Lahiri

We show how the replica method can be used to compute the asymptotic eigenvalue spectrum of a real Wishart product matrix. For unstructured factors, this provides a compact, elementary derivation of a polynomial condition on the Stieltjes…

Disordered Systems and Neural Networks · Physics 2023-01-24 Jacob A. Zavatone-Veth , Cengiz Pehlevan

This paper establishes a natural quantum counterpart of weak equilibration for statistical ensembles in integrable systems. For quantum systems with pure point spectrum, single-time expectation values under unitary evolution are typically…

Dynamical Systems · Mathematics 2026-03-26 Xinyu Liu

The partial trace operation is usually considered in composite quantum systems, to reduce the state on a single subsystem. This operation has a key role in the decoherence effect and quantum measurements. However, partial trace operations…

Quantum Physics · Physics 2024-03-18 Quentin Ansel

Ensembles of random density matrices determined by various probability measures are analysed. A simple and efficient algorithm to generate at random density matrices distributed according to the Bures measure is proposed. This procedure may…

Statistical Mechanics · Physics 2010-03-31 Vladimir Al. Osipov , Hans-Juergen Sommers , Karol Zyczkowski

This study derives a new property of the Wishart distribution when the degree-of-freedom and the size of the matrix parameter of the distribution grow simultaneoulsy. Particularly, the asymptotic normality of the product of four independent…

Statistics Theory · Mathematics 2022-03-29 Koji Tsukuda , Shun Matsuura

We present an efficient algorithm for twirling a multi-qudit quantum state. The algorithm can be used for approximating the twirling operation in an ensemble of physical systems in which the systems cannot be individually accessed. It can…

Quantum Physics · Physics 2007-05-23 Geza Toth , Juan Jose Garcia-Ripoll

Mixed states of a quantum system, represented by density operators, can be decomposed as a statistical mixture of pure states in a number of ways where each decomposition can be viewed as a different preparation recipe. However the fact…

Quantum Physics · Physics 2016-01-26 Sandeep K Goyal , Rajeev Singh , Sibasish Ghosh

Cumulant mapping has been recently suggested [Frasinski, Phys. Chem. Chem. Phys. 24, 207767 (2022)] as an efficient approach to observing multi-particle fragmentation pathways, while bypassing the restrictions of the usual…

Chemical Physics · Physics 2025-04-11 S. Patchkovskii , J. Mikosch

We present an algebraic algorithm for quantum state tomography that leverages measurements of certain observables to estimate structured entries of the underlying density matrix. Under low-rank assumptions, the remaining entries can be…

Quantum Physics · Physics 2026-02-18 Shakir Showkat Sofi , Charlotte Vermeylen , Lieven De Lathauwer

The distribution of entanglement of typical multiparty quantum states is not uniform over the range of the measure utilized for quantifying the entanglement. We intend to find the response to disorder in the state parameters on this…

Quantum Physics · Physics 2022-12-29 George Biswas , Anindya Biswas , Ujjwal Sen

Coherence and entanglement are fundamental concepts in resource theory. The coherence (entanglement) of assistance is the coherence (entanglement) that can be extracted assisted by another party with local measurement and classical…

Quantum Physics · Physics 2021-03-17 Ming-Jing Zhao , Rajesh Pereira , Teng Ma , Shao-Ming Fei

A new method involving particle diagrams is introduced and developed into a rigorous framework for carrying out embedded random matrix calculations. Using particle diagrams and the attendant methodology including loop counting it becomes…

Quantum Physics · Physics 2015-04-01 Rupert A Small