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Related papers: Gauge-Fixing Quantum Density Operators At Scale

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Quantum computers hold promise to enable efficient simulations of the properties of molecules and materials; however, at present they only permit ab initio calculations of a few atoms, due to a limited number of qubits. In order to harness…

Materials Science · Physics 2020-07-07 He Ma , Marco Govoni , Giulia Galli

The dynamics of one-dimensional quantum many-body systems is often numerically simulated with matrix-product states (MPSs). The computational complexity of MPS methods is known to be related to the growth of entropies of reduced density…

Quantum Physics · Physics 2023-08-08 Guillermo Preisser , David Wellnitz , Thomas Botzung , Johannes Schachenmayer

Trading fidelity for scale enables approximate classical simulators such as matrix product states (MPS) to run quantum circuits beyond exact methods. A control parameter, the so-called bond dimension $\chi$ for MPS, governs the allocated…

Quantum Physics · Physics 2023-01-03 Maxime Dupont , Nicolas Didier , Mark J. Hodson , Joel E. Moore , Matthew J. Reagor

The problem of simulatability of quantum processes using classical resources plays a cornerstone role for quantum computing. Quantum circuits can be simulated classically, e.g., using Monte Carlo sampling techniques applied to…

Quantum Physics · Physics 2024-02-09 Denis A. Kulikov , Vsevolod I. Yashin , Aleksey K. Fedorov , Evgeniy O. Kiktenko

We present a systematic approach for constructing steady state density operators of Markovian dissipative evolution for open quantum chain models with integrable bulk interaction and boundary incoherent driving. The construction is based on…

Quantum Physics · Physics 2015-06-16 Enej Ilievski , Bojan Žunkovič

In quantum physics, the density operator completely describes the state. Instead, in classical physics the mean value of every physical quantity is evaluated by means of a probability distribution. We study the possibility to describe pure…

Quantum Physics · Physics 2011-11-09 Alberto Montina

Investigations of quantum and mesoscopic thermodynamics force one to answer two fundamental questions associated with the foundations of statistical mechanics: (i) how does macroscopic irreversibility emerge from microscopic reversibility?…

Quantum Physics · Physics 2019-02-20 Wei-Min Zhang

We present a quantum Monte-Carlo simulation for a pumped atom in a strong coupling cavity with dissipation, where two ordered spatial modes are formed for the atomic probability density, with the peaks distributed either only in the odd…

Quantum Physics · Physics 2015-06-16 Zhen Fang , Baoguo Yang , Xuzong Chen , Xiaoji Zhou

The paper deals with quantum pulse position modulation (PPM), both in the absence (pure states) and in the presence (mixed states) of thermal noise, using the Glauber representation of coherent laser radiation. The objective is to find…

Quantum Physics · Physics 2009-11-16 G. Cariolaro , G. Pierobon

We introduce a way to express compact quantum electrodynamics with dynamical matter on two- and three-dimensional spatial lattices in a gauge redundancy-free manner while preserving translational invariance. By transforming to a rotating…

Quantum Physics · Physics 2020-12-24 Julian Bender , Erez Zohar

We perform quantum simulation on classical and quantum computers and set up a machine learning framework in which we can map out phase diagrams of known and unknown quantum many-body systems in an unsupervised fashion. The classical…

Quantum Physics · Physics 2022-10-21 Korbinian Kottmann

This chapter gives a self-contained review of the how standard open quantum system Hamiltonians can be mapped analytically onto representations in which the environments appear as one dimensional harmonic chains with nearest neighbour…

Quantum Physics · Physics 2011-12-30 Alex W. Chin , Susana F. Huelga , Martin B. Plenio

An alternative approach to decoherence, named non-dynamical decoherence is developed and used to resolve the quantum measurement problem. According to decoherence, the observed system is open to a macroscopic apparatus(together with a…

Quantum Physics · Physics 2015-04-08 Yu-Lei Feng , Yi-Xin Chen

Exact diagonalization is a powerful tool to study fractional quantum Hall (FQH) systems. However, its capability is limited by the exponentially increasing computational cost. In order to overcome this difficulty,…

Strongly Correlated Electrons · Physics 2015-10-01 Zhao Liu , R. N. Bhatt

The density matrix is a positive semidefinite operator of trace 1 characterizing the state of a quantum system. We consider the inverse problem to reconstruct such density matrices from indirect measurements, also known as quantum state…

Numerical Analysis · Mathematics 2026-03-06 Florian Oberender , Thorsten Hohage

We consider a class of interacting particle systems in continuous space of non-gradient type, which are reversible with respect to Poisson point processes with constant density. For these models, a rate of convergence was recently obtained…

Probability · Mathematics 2024-01-19 Chenlin Gu , Jean-Christophe Mourrat , Maximilian Nitzschner

We aim to bridge the gap between quantum coherence, quantum correlations, and nonequilibrium quantum transport in a quantum double-dot (QDD) system interacting with fermionic reservoirs. The system-reservoir coupling is modeled using a…

Quantum Physics · Physics 2025-02-18 Saikumar Krithivasan , Thingujam Yaiphalemba Meitei , Arijit Sen , Md Manirul Ali

It is widely believed that statistical interpretation of quantum mechanics requires that density operators representing quantum states be normalized. We present a description of selective measurements in terms of density operators. The…

Mathematical Physics · Physics 2007-11-15 Wlodzimierz M. Tulczyjew

Quantum computing has recently emerged as a transformative technology. Yet, its promised advantages rely on efficiently translating quantum operations into viable physical realizations. In this work, we use generative machine learning…

Quantum Physics · Physics 2024-05-22 Florian Fürrutter , Gorka Muñoz-Gil , Hans J. Briegel

Molecular dynamics simulations are an invaluable tool in numerous scientific fields. However, the ubiquitous classical force fields cannot describe reactive systems, and quantum molecular dynamics are too computationally demanding to treat…

Chemical Physics · Physics 2022-08-09 Xiangyun Lei , Andrew J. Medford