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We define the projected entropy S(T) at a given temperature T in the context of an Ising model transition matrix calculation as the entropy associated with the distribution of Markov chain realizations in energy-magnetization, E-H, space.…

Statistical Mechanics · Physics 2018-10-17 David Yevick

The Suzuki-Trotter decomposition, which digitalizes quantum time evolution, provides a promising framework for simulating quantum dynamics on quantum hardware and exploring quantum advantage over classical computation. However, conventional…

Quantum Physics · Physics 2025-12-16 Bo Yang , Naoki Negishi

Using the random-cluster representation of the $q$-state Potts models we consider the pooling of data from cluster-update Monte Carlo simulations for different thermal couplings $K$ and number of states per spin $q$. Proper combination of…

Statistical Mechanics · Physics 2009-11-07 Martin Weigel , Wolfhard Janke , Chin-Kun Hu

Thermodynamic properties can be in principle derived from the partition function, which, in many-atom systems, is hard to evaluate as it involves a sum on the accessible microscopic states. Recently, the partition function has been computed…

The quest for improved sampling methods to solve statistical mechanics problems of physical and chemical interest proceeds with renewed efforts since the invention of the Metropolis algorithm, in 1953. In particular, the understanding of…

Quantum Physics · Physics 2021-08-27 Guglielmo Mazzola

We propose incorporating multi-qubit nonunitary operations in Variational Quantum Thermalizers (VQTs). VQTs are hybrid quantum-classical algorithms that generate the thermal (Gibbs) state of a given Hamiltonian, with applications in quantum…

Quantum Physics · Physics 2025-03-28 Elias Zapusek , Kristina Kirova , Walter Hahn , Michael Marthaler , Florentin Reiter

Transition Path Theory (TPT) provides a rigorous framework to investigate the dynamics of rare thermally activated transitions. In this theory, a central role is played by the forward committor function q^+(x), which provides the ideal…

Statistical Mechanics · Physics 2018-08-15 G. Bartolucci , S. Orioli , P. Faccioli

The simulation of quantum systems is one of the flagship applications of near-term NISQ (noisy intermediate-scale quantum) computing devices. Efficiently simulating the rich, non-unitary dynamics of open quantum systems remains challenging…

Quantum Physics · Physics 2024-10-14 Colin Burdine , Enrique P. Blair

Optimal control methods for implementing quantum modules with least amount of relaxative loss are devised to give best approximations to unitary gates under relaxation. The potential gain by optimal control using relaxation parameters…

Quantum Physics · Physics 2011-08-17 T. Schulte-Herbrueggen , A. Spoerl , N. Khaneja , S. J. Glaser

Preparing the thermal density matrix $\rho_{\beta} \propto e^{-\beta H}$ corresponding to a given Hamiltonian $H$ is a task of central interest across quantum many-body physics, and is particularly salient when attempting to study it with…

Quantum Physics · Physics 2026-01-14 Dominik Hahn , S. A. Parameswaran , Benedikt Placke

In the current work we address the problem of quantum process tomography (QPT) in the case of imperfect preparation and measurement of the states which are used for QPT. The fuzzy measurements approach which helps us to efficiently take…

Quantum Physics · Physics 2019-03-21 B. I. Bantysh , D. V. Fastovets , Yu. I. Bogdanov

In quantum information geometry, the curvature of von-Neumann entropy and relative entropy induce a natural metric on the space of mixed quantum states. Here we use this information metric to construct a random matrix ensemble for states…

Quantum Physics · Physics 2026-01-26 Harry J. D. Miller

We present a general protocol for estimating $M$ observables from only $\mathcal{O}(\log (M)/\varepsilon^2)$ copies of a Gibbs state whose Hamiltonian is accessible. The protocol uses single-copy, nonadaptive measurements and uses a total…

Quantum Physics · Physics 2026-03-18 Chi-Fang Chen , András Gilyén

A generic method to investigate many-body continuous-variable systems is pedagogically presented. It is based on the notion of matrix product states (so-called MPS) and the algorithms thereof. The method is quite versatile and can be…

Strongly Correlated Electrons · Physics 2013-05-29 S. Iblisdir , R. Orus , J. I. Latorre

Simulating the dynamic evolutions of physical and molecular systems in a quantum computer is of fundamental interest in many applications. Its implementation requires efficient quantum simulation algorithms. The Lie-Trotter-Suzuki…

Quantum Physics · Physics 2022-11-15 Yue Yu , Yulin Chi , Chonghao Zhai , Jieshan Huang , Qihuang Gong , Jianwei Wang

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

As one of the most prominent platforms for analog quantum simulators, Rydberg atom arrays are a promising tool for exploring quantum phases and transitions. While the ground state properties of one-dimensional Rydberg systems are already…

Quantum Physics · Physics 2024-10-02 Nora Reinić , Daniel Jaschke , Darvin Wanisch , Pietro Silvi , Simone Montangero

We demonstrate complete characterization of a two-qubit entangling process - a linear optics controlled-NOT gate operating with coincident detection - by quantum process tomography. We use maximum-likelihood estimation to convert the…

Quantum Physics · Physics 2008-11-26 J. L. O'Brien , G. J. Pryde , A. Gilchrist , D. F. V. James , N. K. Langford , T. C. Ralph , A. G. White

We propose a hybrid approach to simulate quantum many body dynamics by combining Trotter based quantum algorithm with classical dynamic mode decomposition. The interest often lies in estimating observables rather than explicitly obtaining…

Quantum Physics · Physics 2023-07-31 Niladri Gomes , Jia Yin , Siyuan Niu , Chao Yang , Wibe Albert de Jong

For the simulation of equilibrium states and finite-temperature response functions of strongly-correlated quantum many-body systems, we compare the efficiencies of two different approaches in the framework of the density matrix…

Strongly Correlated Electrons · Physics 2017-01-03 Moritz Binder , Thomas Barthel