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We show that a novel, general phase space mapping Hamiltonian for nonadiabatic systems, which is reminiscent of the renowned Meyer-Miller mapping Hamiltonian, involves a commutator variable matrix rather than the conventional…

Chemical Physics · Physics 2021-08-19 Xin He , Baihua Wu , Zhihao Gong , Jian Liu

Nonadiabatic dynamical processes are one of the most important quantum mechanical phenomena in chemical, materials, biological, and environmental molecular systems, where the coupling between different electronic states is either inherent…

Chemical Physics · Physics 2022-05-24 Jian Liu , Xin He , Baihua Wu

We propose a trajectory-based method for simulating nonadiabatic dynamics in molecular systems with two coupled electronic states. Employing a quantum-mechanically exact mapping of the two-level problem to a spin-1/2 coherent state, we…

Chemical Physics · Physics 2020-03-03 Johan E. Runeson , Jeremy O. Richardson

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

Dynamics of neutral atoms in nonuniform magnetic fields, typical of quadrupole magnetic traps, is considered by applying an accurate method for solving nonlinear systems of differential equations. This method is more general than the…

Atomic Physics · Physics 2009-10-30 V. I. Yukalov

We present a thermodynamic model which explains the presence of a negative slope in the melt curve, as observed in systems as diverse as the alkali metals and molecular hydrogen at high pressure. We assume that components of the system can…

Absolute temperature, the fundamental temperature scale in thermodynamics, is usually bound to be positive. Under special conditions, however, negative temperatures - where high-energy states are more occupied than low-energy states - are…

Noncommutative features are introduced into a relativistic quantum field theory model of nuclear matter, the quantum hadrodynamics-I nuclear model (QHD-I). It is shown that the nuclear matter equation of state (NMEoS) depends on the…

High Energy Physics - Phenomenology · Physics 2015-12-09 Orfeu Bertolami , Hodjat Mariji

The maximum entropy principle (MEP) apparently allows us to derive, or justify, fundamental results of equilibrium statistical mechanics. Because of this, a school of thought considers the MEP as a powerful and elegant way to make…

Statistical Mechanics · Physics 2015-12-09 Gennaro Auletta , Lamberto Rondoni , Angelo Vulpiani

We present a new partially linearized mapping-based approach for approximating real-time quantum correlation functions in condensed-phase nonadiabatic systems, called spin-PLDM. Within a classical trajectory picture, partially linearized…

Chemical Physics · Physics 2021-02-03 J. R. Mannouch , J. O. Richardson

A new methodology of simulating nonadiabatic dynamics using frozen-width Gaussian wavepackets within the moving crude adiabatic representation with the on-the-fly evaluation of electronic structure is presented. The main feature of the new…

Chemical Physics · Physics 2018-04-04 Loïc Joubert-Doriol , Artur F. Izmaylov

Identifying extensively degenerate zero-temperature states is key in characterizing spin-liquid-candidate materials and spin ices. In experiments, finding zero-point entropy (ZPE) is often attempted by measuring the entropy released by a…

Mesoscale and Nanoscale Physics · Physics 2026-04-02 Sergey Syzranov , Arthur P. Ramirez

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

Do negative absolute temperatures matter physics and specifically Statistical Physics? We provide evidence that we can certainly answer positively to this vexata quaestio. The great majority of models investigated by statistical mechanics…

Statistical Mechanics · Physics 2021-07-07 Marco Baldovin , Stefano Iubini , Roberto Livi , Angelo Vulpiani

The free energy principle (FEP) states that any dynamical system can be interpreted as performing Bayesian inference upon its surrounding environment. In this work, we examine in depth the assumptions required to derive the FEP in the…

Neurons and Cognition · Quantitative Biology 2022-05-23 Miguel Aguilera , Beren Millidge , Alexander Tschantz , Christopher L. Buckley

In the standard cosmological framework of the 0th-order FLRW metric and the use of perfect fluids in the stress-energy tensor, dark energy with an equation-of-state parameter $w < -1$ (known as phantom dark energy) implies negative kinetic…

General Relativity and Quantum Cosmology · Physics 2015-10-07 Kevin J. Ludwick

We develop a geometric formalism suited for describing the quantum thermodynamics of a certain class of nanoscale systems (whose density matrix is expressible in the McLennan--Zubarev form) at any arbitrary non-equilibrium steady state. It…

Statistical Mechanics · Physics 2021-10-04 Aritra Ghosh , Malay Bandyopadhyay , Chandrasekhar Bhamidipati

Nonlinearity introduced in slow-roll inflation will produce weakly non-Gaussian CMB temperature fluctuations. We have simulated non-Gaussian large scale CMB maps (including COBE-DMR constraints) introducing an additional quadratic term in…

Astrophysics · Physics 2009-11-07 L. Cayon , E. Martinez-Gonzalez , F. Argueso , A. J. Banday , K. M. Gorski

Recently proposed non-adiabatic ring polymer molecular dynamics (NRPMD) approach has shown to provide accurate quantum dynamics by incorporating explicit electronic state descriptions and nuclear quantizations. Here, we present a rigorous…

Chemical Physics · Physics 2019-07-24 Sutirtha N. Chowdhury , Pengfei Huo

In this work, we perform a detailed dynamical analysis for the cosmological applications of a nonminimal torsion-matter coupled gravity. Two alternative formalisms are proposed, which enable one to choose between the easier approach for a…

General Relativity and Quantum Cosmology · Physics 2016-01-20 Sante Carloni , Francisco S. N. Lobo , Giovanni Otalora , Emmanuel N. Saridakis
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