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Related papers: On the complexity of quantum partition functions

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In this paper we develop a quantum algorithm to realize finite temperature simulation on a quantum computer. As quantum computers use real-time evolution we did not use the imaginary time methods popular on classical algorithms. Instead, we…

Quantum Physics · Physics 2019-11-11 Raffaele Miceli , Michael McGuigan

The key problem of statistical physics standing over one hundred years is how to exactly calculate the partition function (or free energy) of many-body interaction systems, which severely hinders application of the theory for realistic…

Statistical Mechanics · Physics 2019-04-26 Bo-Yuan Ning , Le-Cheng Gong , Tsu-Chien Weng , Xi-Jing Ning

Learning the Hamiltonian underlying a quantum many-body system in thermal equilibrium is a fundamental task in quantum learning theory and experimental sciences. To learn the Gibbs state of local Hamiltonians at any inverse temperature…

Quantum Physics · Physics 2025-04-04 Chi-Fang Chen , Anurag Anshu , Quynh T. Nguyen

Understanding the mechanisms responsible for the equilibration of isolated quantum many-body systems is a long-standing open problem. In this work we obtain a statistical relationship between the equilibration properties of Hamiltonians and…

Quantum Physics · Physics 2013-03-27 Lluis Masanes , Augusto J. Roncaglia , Antonio Acin

Long-range quantum systems, in which the interactions decay as $1/r^{\alpha}$, are of increasing interest due to the variety of experimental set-ups in which they naturally appear. Motivated by this, we study fundamental properties of…

Quantum Physics · Physics 2026-01-08 Jorge Sánchez-Segovia , Jan T. Schneider , Álvaro M. Alhambra

We address the question of how a quantum computer can be used to simulate experiments on quantum systems in thermal equilibrium. We present two approaches for the preparation of the equilibrium state on a quantum computer. For both…

Quantum Physics · Physics 2009-10-31 Barbara M. Terhal , David P. DiVincenzo

We study the problem of learning the Hamiltonian of a quantum many-body system given samples from its Gibbs (thermal) state. The classical analog of this problem, known as learning graphical models or Boltzmann machines, is a well-studied…

Quantum Physics · Physics 2021-05-26 Anurag Anshu , Srinivasan Arunachalam , Tomotaka Kuwahara , Mehdi Soleimanifar

We describe an efficient approximation algorithm for evaluating the ground-state energy of the classical Ising Hamiltonian with linear terms on an arbitrary planar graph. The running time of the algorithm grows linearly with the number of…

Quantum Physics · Physics 2009-09-16 Nikhil Bansal , Sergey Bravyi , Barbara M. Terhal

A quantum thermodynamic system is described by a Hamiltonian and a list of conserved, non-commuting charges, and a fundamental goal is to determine the minimum energy of the system subject to constraints on the charges. Recently, [Liu et…

Estimating the ground-state energy of Hamiltonians is a fundamental task for which it is believed that quantum computers can be helpful. Several approaches have been proposed toward this goal, including algorithms based on quantum phase…

Quantum Physics · Physics 2025-11-26 Dhrumil Patel , Daniel Koch , Saahil Patel , Mark M. Wilde

Simulating the nonequilibrium dynamics of thermal states is a fundamental problem across scales from high energy to condensed matter physics. Quantum computers may provide a way to solve this problem efficiently. Preparing a thermal state…

Quantum Physics · Physics 2023-11-03 Jason Saroni , Henry Lamm , Peter P. Orth , Thomas Iadecola

Quantum dynamics can be analyzed via the structure of energy eigenstates. However, in the many-body setting, preparing eigenstates associated with finite temperatures requires time scaling exponentially with system size. In this work we…

Quantum Physics · Physics 2024-07-11 Samuel J. Garratt , Soonwon Choi

Free classical particles have well-defined momentum and position, while free quantum particles have well-defined momentum but a position fully delocalized over the sample volume. We develop a many-body formalism based on wave-packet…

Quantum Physics · Physics 2017-11-07 Aurélia Chenu , Monique Combescot

The ground state energy and the free energy of Quantum Local Hamiltonians are fundamental quantities in quantum many-body physics, however, it is QMA-Hard to estimate them in general. In this paper, we develop new techniques to find…

Quantum Physics · Physics 2023-08-08 Thiago Bergamaschi

The development of novel quantum many-body computational algorithms relies on robust benchmarking. However, generating such benchmarks is often hindered by the massive computational resources required for exact diagonalization or quantum…

Strongly Correlated Electrons · Physics 2025-12-29 Wei-Bo He , Yun-Tong Yang , Hong-Gang Luo

We present two algorithms, one quantum and one classical, for estimating partition functions of quantum spin Hamiltonians. The former is a DQC1 (Deterministic quantum computation with one clean qubit) algorithm, and the first such for…

Quantum Physics · Physics 2023-02-01 Andrew Jackson , Theodoros Kapourniotis , Animesh Datta

Thermalization is the process through which a physical system evolves toward a state of thermal equilibrium. Determining whether or not a physical system will thermalize from an initial state has been a key question in condensed matter…

Quantum Physics · Physics 2026-01-05 Dhruv Devulapalli , T. C. Mooney , James D. Watson

Computing finite temperature properties of a quantum many-body system is key to describing a broad range of correlated quantum many-body physics from quantum chemistry and condensed matter to thermal quantum field theories. Quantum…

Quantum Physics · Physics 2023-08-16 Hai Wang , Jue Nan , Tao Zhang , Xingze Qiu , Wenlan Chen , Xiaopeng Li

We consider a family of quantum spin systems which includes as special cases the ferromagnetic XY model and ferromagnetic Ising model on any graph, with or without a transverse magnetic field. We prove that the partition function of any…

Quantum Physics · Physics 2017-09-13 Sergey Bravyi , David Gosset

The problem of simulating the thermal behavior of quantum systems remains a central open challenge in quantum computing. Unlike well-established quantum algorithms for unitary dynamics, \emph{provably efficient} algorithms for preparing…

Quantum Physics · Physics 2026-05-14 Dominik Hahn , Ryan Sweke , Abhinav Deshpande , Oles Shtanko