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We derive an integral-free thermodynamic perturbation series expansion for quantum partition functions which enables an analytical term-by-term calculation of the series. The expansion is carried out around the partition function of the…

Statistical Mechanics · Physics 2018-05-23 Itay Hen

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

We describe a method to compute thermodynamic quantities in the harmonic approximation for identical bosons and fermions in an external confining field. We use the canonical partition function where only energies and their degeneracies…

Quantum Physics · Physics 2012-02-16 J. R. Armstrong , N. T. Zinner , D. V. Fedorov , A. S. Jensen

We present a new technique for a numerical analysis of the phase structure of the 2D Hubbard model as a function of the hole chemical potential. The grand canonical partition function for the model is obtained via Monte Carlo simulations.…

High Energy Physics - Lattice · Physics 2009-10-22 I. M. Barbour , E. G. Klepfish

Efficient sampling from ensembles of Hamiltonian cycles is critical for predicting the thermodynamic properties of compact polymers, with applications including modeling protein and RNA folding and designing soft materials. Although…

Quantum Physics · Physics 2026-03-16 Davide Rattacaso , Daniel Jaschke , Antonio Trovato , Ilaria Siloi , Simone Montangero

For the calculation of the partition function $\mathcal{Z}$ of small, isolated and interacting many body systems an improvement with respect to previous formulations is presented. By including anharmonicities and employing a variational…

Nuclear Theory · Physics 2009-11-10 Christian Rummel , Helmut Hofmann

Stoquastic Hamiltonians are characterized by the property that their off-diagonal matrix elements in the standard product basis are real and non-positive. Many interesting quantum models fall into this class including the Transverse field…

Quantum Physics · Physics 2017-01-13 Sergey Bravyi

In order to analyze spectrum from the interstellar medium (ISM), spectrum of the molecule of interest is recorded in a laboratory, and accurate rotational and centrifugal distortion constants are derived. By using these constants, one can…

Astrophysics of Galaxies · Physics 2015-07-20 M. K. Sharma , Monika Sharma , Suresh Chandra

A multi-band effective-mass Hamiltonian is derived for lattice-matched semiconductor nanostructures in a slowly varying external magnetic field. The theory is derived from the first-principles magnetic-field coupling Hamiltonian of Pickard…

Materials Science · Physics 2007-05-23 Bradley A. Foreman

We derive the microcanonical partition function of the ideal relativistic quantum gas of spinless bosons in a quantum field framework as an expansion over fixed multiplicities. Our calculation generalizes well known expressions in…

Nuclear Theory · Physics 2008-11-26 F. Becattini , L. Ferroni

The gravitational field in a spatially finite region is described as a microcanonical system. The density of states $\nu$ is expressed formally as a functional integral over Lorentzian metrics and is a functional of the geometrical boundary…

General Relativity and Quantum Cosmology · Physics 2009-10-22 J. David Brown , James W. York

We present a geometric and dynamical approach to the micro-canonical ensemble of classical Hamiltonian systems. We generalize the arguments in \cite{Rugh} and show that the energy-derivative of a micro-canonical average is itself…

chao-dyn · Physics 2009-10-30 Hans Henrik Rugh

Non-Gaussian distributions in cosmology are commonly evaluated with Monte Carlo Markov-chain methods, as the Fisher-matrix formalism is restricted to the Gaussian case. The Metropolis-Hastings algorithm will provide samples from the…

Cosmology and Nongalactic Astrophysics · Physics 2023-05-15 Lennart Röver , Heinrich von Campe , Maximilian Philipp Herzog , Rebecca Maria Kuntz , Björn Malte Schäfer

Boltzmann sampling based on Metropolis algorithm has been extensively used for simulating a canonical ensemble. An estimate of a mechanical property, like energy, of an equilibrium system, can be made by averaging over a large number…

Statistical Mechanics · Physics 2017-10-04 K P N Murthy

We show here that the Hamiltonian for an electronic system may be written exactly in terms of fluctuation operators that transition constituent fragments between internally correlated states, accounting rigorously for inter-fragment…

Chemical Physics · Physics 2019-05-24 Anthony D. Dutoi , Yuhong Liu

The Metropolis Monte Carlo algorithm with the Finite Element method applied to compute electrostatic interaction energy between charge densities is described in this work. By using the Finite Element method to integrate numerically the…

Statistical Mechanics · Physics 2010-09-08 Martial Mazars

The aim of the present paper is to provide a preliminary investigation of the thermodynamics of particles obeying monotone statistics. To render the potential physical applications realistic, we propose a modified scheme called…

Mathematical Physics · Physics 2023-01-27 Fabio Ciolli , Francesco Fidaleo , Chiara Marullo

Various aspects of the statistics of work performed by an external classical force on a quantum mechanical system are elucidated for a driven harmonic oscillator. In this special case two parameters are introduced that are sufficient to…

Statistical Mechanics · Physics 2009-06-05 Peter Talkner , P. Sekhar Burada , Peter Hänggi

Hamiltonian dynamics can be used to produce distant proposals for the Metropolis algorithm, thereby avoiding the slow exploration of the state space that results from the diffusive behaviour of simple random-walk proposals. Though…

Computation · Statistics 2021-06-30 Radford M. Neal

The relaxation function is the cornerstone to perform calculations in weakly driven processes. Properties that such a function should obey are already established, but the difficulty in its calculation is still an issue to be overcome. In…

Statistical Mechanics · Physics 2024-07-11 Pierre Nazé