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We show how the path-integral formulation of quantum statistical mechanics can be used to construct practical {\em ab initio} techniques for computing the chemical potential of molecules adsorbed on surfaces, with full inclusion of quantum…

Materials Science · Physics 2015-05-18 D. Alfe` , M. J. Gillan

In the long-time pursuit of the solution to calculate the partition function (or free energy) of condensed matter, Monte-Carlo-based nested sampling should be the state-of-the-art method, and very recently, we established a direct integral…

Statistical Mechanics · Physics 2020-01-08 Le-Cheng Gong , Bo-Yuan Ning , Tsu-Chien Weng , Xi-Jing Ning

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…

We derive an exact, continuous-variable path integral (PI) representation of the canonical partition function for electronically nonadiabatic systems. Utilizing the Stock-Thoss (ST) mapping for an N-level system, matrix elements of the…

Statistical Mechanics · Physics 2011-07-28 Nandini Ananth , Thomas F. Miller

The recently introduced nested sampling algorithm allows the direct and efficient calculation of the partition function of atomistic systems. We demonstrate its applicability to condensed phase systems with periodic boundary conditions by…

Statistical Mechanics · Physics 2014-01-09 Lívia B. Pártay , Albert P. Bartók , Gábor Csányi

We present a method to compute real-time path integrals numerically, by Monte-Carlo sampling on near-Lefschetz thimbles. We present a collection of tools based on the Lefschetz thimble methods, which together provide an alternative to…

High Energy Physics - Lattice · Physics 2025-02-28 Zong-Gang Mou , Paul M. Saffin , Anders Tranberg

We have developed a numerically exact approach to compute real-time path integral expressions for quantum transport problems out of equilibrium. The scheme is based on a deterministic iterative summation of the path integral (ISPI) for the…

Mesoscale and Nanoscale Physics · Physics 2015-06-15 S. Weiss , R. Hützen , D. Becker , J. Eckel , R. Egger , M. Thorwart

Quantum embedding is an appealing route to fragment a large interacting quantum system into several smaller auxiliary `cluster' problems to exploit the locality of the correlated physics. In this work we critically review approaches to…

Strongly Correlated Electrons · Physics 2023-07-19 Max Nusspickel , Basil Ibrahim , George H. Booth

We propose a phase-space path integral formulation of noncommutative quantum mechanics, and prove its equivalence to the operatorial formulation. As an illustration, the partition function of a noncommutative two-dimensional harmonic…

High Energy Physics - Theory · Physics 2009-11-07 Ciprian Acatrinei

Vibrational spectra of condensed and gas-phase systems containing light nuclei are influenced by their quantum-mechanical behaviour. The quantum dynamics of light nuclei can be approximated by the imaginary time path integral (PI)…

Chemical Physics · Physics 2022-11-23 Félix Musil , Iryna Zaporozhets , Frank Noé , Cecilia Clementi , Venkat Kapil

Path integral Monte Carlo with Green's function analysis allows the sampling of quantum mechanical properties of molecules at finite temperature. While a high-precision computation of the energy of the Born-Oppenheimer surface from path…

Quantum Physics · Physics 2007-05-23 Daejin Shin , Ming-Chak Ho , J. Shumway

The precise description of quantum nuclear fluctuations in atomistic modelling is possible by employing path integral techniques, which involve a considerable computational overhead due to the need of simulating multiple replicas of the…

Chemical Physics · Physics 2017-03-23 Venkat Kapil , Jörg Behler , Michele Ceriotti

Path integrals for particles in curved spaces can be used to compute trace anomalies in quantum field theories, and more generally to study properties of quantum fields coupled to gravity in first quantization. While their construction in…

High Energy Physics - Theory · Physics 2017-04-26 Fiorenzo Bastianelli , Olindo Corradini , Edoardo Vassura

We present a simple and accurate computational method, which facilitates ab-initio path-integral molecular dynamics simulations, where the quantum mechanical nature of the nuclei is explicitly taken into account, at essentially no…

Chemical Physics · Physics 2016-04-21 Chris John , Thomas Spura , Scott Habershon , Thomas D. Kühne

This article presents a new method to compute matrices from numerical simulations based on the ideas of sparse sampling and compressed sensing. The method is useful for problems where the determination of the entries of a matrix constitutes…

Chemical Physics · Physics 2014-10-21 Jacob N. Sanders , Xavier Andrade , Alán Aspuru-Guzik

We have developed a numerical approach to compute real-time path integral expressions for quantum transport problems out of equilibrium. The scheme is based on a deterministic iterative summation of the path integral (ISPI) for the…

Mesoscale and Nanoscale Physics · Physics 2008-05-16 S. Weiss , J. Eckel , M. Thorwart , R. Egger

We present a quantum algorithm that additively approximates the value of a tensor network to a certain scale. When combined with existing results, this provides a complete problem for quantum computation. The result is a simple new way of…

Quantum Physics · Physics 2010-02-09 Itai Arad , Zeph Landau

In this paper, we demonstrate the efficiency of simulations via direct computation of the partition function under various macroscopic conditions, such as different temperatures or volumes. The method can compute partition functions by…

Statistical Mechanics · Physics 2011-11-09 Cheng Zhang , Jianpeng Ma

We present a systematic study of the nested sampling algorithm based on the example of the Potts model. This model, which exhibits a first order phase transition for $q>4$, exemplifies a generic numerical challenge in statistical physics:…

Computational Physics · Physics 2017-12-12 Manuel J. Pfeifenberger , Michael Rumetshofer , Wolfgang von der Linden

We present a method to approximate partition functions of quantum systems using mixed-state quantum computation. For positive semi-definite Hamiltonians, our method has expected running-time that is almost linear in $(M/(\epsilon_{\rm…

Quantum Physics · Physics 2021-03-24 Anirban N. Chowdhury , Rolando D. Somma , Yigit Subasi
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