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Related papers: On the complexity of quantum partition functions

200 papers

Simulation of warm dense matter requires computational methods that capture both quantum and classical behavior efficiently under high-temperature, high-density conditions. Currently, density functional theory molecular dynamics is used to…

Chemical Physics · Physics 2015-10-21 Attila Cangi , Aurora Pribram-Jones

We provide a pure state formulation for hydrodynamic dynamics of isolated quantum many-body systems. A pure state describing quantum systems in local thermal equilibrium is constructed, which we call a local thermal pure quantum ($\ell$TPQ)…

Statistical Mechanics · Physics 2021-07-06 Shoichiro Tsutsui , Masaru Hongo , Shintaro Sato , Takahiro Sagawa

We present a quantum algorithm to prepare the thermal Gibbs state of interacting quantum systems. This algorithm sets a universal upper bound D^alpha on the thermalization time of a quantum system, where D is the system's Hilbert space…

Quantum Physics · Physics 2013-05-29 David Poulin , Pawel Wocjan

We discuss how to calculate genuine multipartite quantum and classical correlations in symmetric, spatially invariant, mixed $n$-qubit density matrices. We show that the existence of symmetries greatly reduces the amount of free parameters…

Quantum Physics · Physics 2016-10-24 Gian Luca Giorgi , Steve Campbell

We provide several quantum algorithms for continuous optimization that do not require gradient estimation. Instead, we encode the optimization problem into the dynamics of a physical system and coherently simulate the time evolution. We…

Quantum Physics · Physics 2026-03-18 Ahmet Burak Catli , Sophia Simon , Nathan Wiebe

A calculation of the classical analogue for the quantum wave function and local denity of states, in energy representation, is presented for simple Hamiltonian systems. Sucha analogous were proposed by M. V. Berry and A. voros considering…

Chaotic Dynamics · Physics 2012-12-24 H. Hernández-Saldaña

The new mathematical framework based on the free energy of pure classical fluids presented in [R. D. Rohrmann, Physica A 347, 221 (2005)] is extended to multi-component systems to determine thermodynamic and structural properties of…

Statistical Mechanics · Physics 2008-11-26 R. D. Rohrmann , J. Zorec

Due to the limitations of present-day quantum hardware, it is especially critical to design algorithms that make the best possible use of available resources. When simulating quantum many-body systems on a quantum computer, straightforward…

Quantum Physics · Physics 2021-04-07 Olivia Di Matteo , Anna McCoy , Peter Gysbers , Takayuki Miyagi , R. M. Woloshyn , Petr Navrátil

We present a quantum algorithm for simulating the dynamics of a first-quantized Hamiltonian in real space based on the truncated Taylor series algorithm. We avoid the possibility of singularities by applying various cutoffs to the system…

Quantum Physics · Physics 2017-07-07 Ian D. Kivlichan , Nathan Wiebe , Ryan Babbush , Alan Aspuru-Guzik

Electron-electron correlation forms the basis of difficulties encountered in many-body problems. Accurate treatment of the correlation problem is likely to unravel some nice physical properties of matter embedded in this correlation. In an…

Quantum Physics · Physics 2022-03-24 Eric Ouma Jobunga

{Many-body quantum states at thermal equilibrium are ubiquitous in nature. Investigating their dynamical properties is a formidable task due to the complexity of the Hilbert space they live in. Quantum computers may have the potential to…

Quantum Physics · Physics 2024-07-25 Mirko Consiglio , Tony J. G. Apollaro

The ultimate precision of any measurement of the temperature of a quantum system is the inverse of the local quantum thermal susceptibility [De Pasquale et al., Nature Communications 7, 12782 (2016)] of the subsystem with whom the…

Quantum Physics · Physics 2017-05-24 Giacomo De Palma , Antonella De Pasquale , Vittorio Giovannetti

The Green's function plays a crucial role when studying the nature of quantum many-body systems, especially strongly-correlated systems. Although the development of quantum computers in the near future may enable us to compute energy…

Quantum Physics · Physics 2020-08-25 Suguru Endo , Iori Kurata , Yuya O. Nakagawa

Interactions between particles are usually a resource for quantum computing, making quantum many-body systems intractable by any known classical algorithm. In contrast, noise is typically considered as being inimical to quantum many-body…

Quantum Physics · Physics 2021-10-29 Oles Shtanko , Abhinav Deshpande , Paul S. Julienne , Alexey V. Gorshkov

We give a quasi-polynomial time classical algorithm for estimating the ground state energy and for computing low energy states of quantum impurity models. Such models describe a bath of free fermions coupled to a small interacting subsystem…

Quantum Physics · Physics 2018-10-23 Sergey Bravyi , David Gosset

This work continues the investigation in two recent papers on the quantum thermodynamics of spacetimes, 1) placing what was studied in [1] for thermal quantum fields in the context of early universe cosmology, and 2) extending the…

High Energy Physics - Theory · Physics 2024-11-26 Jen-Tsung Hsiang , Yu-Cun Xie , Bei-Lok Hu

This paper investigates the thermodynamics of a large class of non-Hermitian, $PT$-symmetric oscillators, whose energy spectrum is entirely real. The spectrum is estimated by second-order WKB approximation, which turns out to be very…

Quantum Physics · Physics 2014-11-18 H. F. Jones , E. S. Moreira

In this work, we consider a fundamental task in quantum many-body physics - finding and learning ground states of quantum Hamiltonians and their properties. Recent works have studied the task of predicting the ground state expectation value…

Quantum Physics · Physics 2025-01-16 Štěpán Šmíd , Roberto Bondesan

Despite progress in quantum Hamiltonian complexity, little is known about the computational complexity of quantum physics at the thermodynamic limit. Even defining the problem is not straight forward. We study the complexity of estimating…

Quantum Physics · Physics 2021-11-09 Dorit Aharonov , Sandy Irani

While questions on quantum simulation of ground state physics are mostly focussed on the realization of effective interactions, most work on quantum simulation of thermal physics explores the realization of dynamics towards a thermal mixed…