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The geometric phases of the cyclic states of a generalized harmonic oscillator with nonadiabatic time-periodic parameters are discussed in the framework of squeezed state. It is shown that the cyclic and quasicyclic squeezed states…

Quantum Physics · Physics 2009-10-31 Jie Liu , Bambi Hu , Baowen Li

The quantum geometric tensor has established itself as a general framework for the analysis and detection of equilibrium phase transitions in isolated quantum systems. We propose a novel generalization of the quantum geometric tensor, which…

Quantum Physics · Physics 2025-02-27 Pavel Orlov , Georgy V. Shlyapnikov , Denis V. Kurlov

In this study we consider the Hamiltonian approach for the construction of a map for a system with nonlinear resonant interaction, including phase trapping and phase bunching effects. We derive basic equations for a single resonant…

Nonadiabatic ring-polymer molecular dynamics employs the mapping approach to describe nonadiabatic effects within the ring-polymer ansatz. In this paper, it is generalized to allow for the nuclear and electronic degrees of freedom to be…

Chemical Physics · Physics 2017-08-23 Jeremy O. Richardson , Philipp Meyer , Marc-Oliver Pleinert , Michael Thoss

Choosing an appropriate representation of the molecular Hamiltonian is one of the challenges faced by simulations of the nonadiabatic quantum dynamics around a conical intersection. The adiabatic, exact quasidiabatic, and strictly diabatic…

Chemical Physics · Physics 2024-09-26 Seonghoon Choi , Jiří Vaníček

We investigate consequences of allowing the Hilbert space of a quantum system to have a time-dependent metric. For a given possibly nonstationary quantum system, we show that the requirement of having a unitary Schreodinger time-evolution…

Quantum Physics · Physics 2015-06-26 Ali Mostafazadeh

We present an approach for eliminating the gauge freedom for derivative couplings in nonadiabatic dynamics in the presence of geometric phase effects. This approach relies on a bottom-up construction of a parametric quantum Hamiltonian in…

Chemical Physics · Physics 2023-04-18 Alex Krotz , Roel Tempelaar

We study the statistical mechanics of a general Hamiltonian system in the context of symplectic structure of the corresponding phase space. This covariant formalism reveals some interesting correspondences between properties of the phase…

General Relativity and Quantum Cosmology · Physics 2015-07-10 V. Hosseinzadeh , M. A. Gorji , K. Nozari , B. Vakili

An adequate characterization of the dynamics of Hamiltonian systems at physically relevant scales has been largely lacking. Here we investigate this fundamental problem and we show that the finite-scale Hamiltonian dynamics is governed by…

Chaotic Dynamics · Physics 2007-05-23 Adilson E. Motter , Alessandro P. S. de Moura , Celso Grebogi , Holger Kantz

We introduce noncommutative phase spaces by minimal couplings (usual one, dual one and their mixing). We then realize some of them as coadjoint orbits of the anisotropic Newton-Hooke groups in two- and three-dimensional spaces. Through…

Mathematical Physics · Physics 2011-12-20 Ancille Ngendakumana , Joachim Nzotungicimpaye , Leonardt Todjihounde

Diabatization of the molecular Hamiltonian is a standard approach to removing the singularities of nonadiabatic couplings at conical intersections of adiabatic potential energy surfaces. In general, it is impossible to eliminate the…

Chemical Physics · Physics 2021-03-26 Seonghoon Choi , Jiří Vaníček

Quantum fluctuations driven by non-stoquastic Hamiltonians have been conjectured to be an important and perhaps essential missing ingredient for achieving a quantum advantage with adiabatic optimization. We introduce a transformation that…

Quantum Physics · Physics 2020-09-30 Elizabeth Crosson , Tameem Albash , Itay Hen , A. P. Young

We investigate the relation between the phase space structure of Hamiltonian and non-Hamiltonian deterministic thermostats. We show that phase space structures governing reaction dynamics in Hamiltonian systems map to the same type of phase…

Statistical Mechanics · Physics 2008-10-21 Gregory S. Ezra , Stephen Wiggins

Understanding how non-adiabatic terms affect quantum dynamics is fundamental to improving various protocols for quantum technologies. We present a novel approach to computing the Adiabatic Gauge Potential (AGP), which gives information on…

Quantum Physics · Physics 2025-01-15 Ewen D C Lawrence , Sebastian F J Schmid , Ieva Čepaitė , Peter Kirton , Callum W Duncan

Mixed-quantum-classical molecular dynamics simulation implies an effective measurement on the electronic states owing to continuously tracking the atomic forces.Based on this insight, we propose a quantum trajectory mean-field approach for…

Chemical Physics · Physics 2014-08-08 Wei Feng , Luting Xu , Xin-Qi Li , Weihai Fang , YiJing Yan

In this paper, non-Hamiltonian systems with holonomic constraints are treated by a generalization of Dirac's formalism. Non-Hamiltonian phase space flows can be described by generalized antisymmetric brackets or by general Liouville…

Statistical Mechanics · Physics 2009-11-11 Alessandro Sergi

The quantum-classical Liouville equation offers a rigorous approach to nonadiabatic quantum dynamics based on surface hopping type trajectories. However, in practice the applicability of this approach has been limited to short times owing…

Chemical Physics · Physics 2015-06-16 Aaron Kelly , Thomas E. Markland

Chemical relaxation phenomena, including photochemistry and electron transfer processes, form a vigorous area of research in which nonadiabatic dynamics plays a fundamental role. Here, we show that for nonadiabatic dynamics with two…

Chemical Physics · Physics 2022-07-20 Yanze Wu , Xuezhi Bian , Jonathan Rawlinson , Robert G. Littlejohn , Joseph E. Subotnik

A new scheme of realizing the nonadiabatic conditional geometric phase shift via a noncoplanar (and coiled) fiber system is presented in this Letter. It is shown that the effective Hamiltonian that describes the interaction of polarized…

Quantum Physics · Physics 2007-05-23 Jian Qi Shen

Direct dynamics methods using Gaussian wavepackets have to rely only on local properties, such as gradients and hessians at the center of the wavepacket, so as to be compatible with the usual quantum chemistry methods. Matrix elements of…

Chemical Physics · Physics 2016-04-26 Alexander Humeniuk , Roland Mitric