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Simulations of chemical dynamics are a powerful means for understanding chemistry. However, classical computers struggle to simulate many chemical processes, especially non-adiabatic ones, where the Born-Oppenheimer approximation breaks…

In the pursuit of numerically identifying the ground state of quantum many-body systems, approximate quantum wavefunction ansatzes are commonly employed. This study focuses on the spectral decomposition of these approximate quantum…

Quantum Physics · Physics 2025-08-29 Yu-Qin Chen , Shi-Xin Zhang

We formulate a canonical quantization of Equilibrium Thermodynamics by applying Dirac's theory of constrained systems. Thermodynamic variables are treated as conjugate pairs of coordinates and momenta, allowing extensive and intensive…

Quantum Physics · Physics 2025-11-19 Luis F. Santos , Victor Hugo M. Ramos , Danilo Cius , Mario C. Baldiotti , Bárbara Amaral

Nonequilibrium dynamics of quantum many-body systems is challenging for classical computing, providing opportunities for demonstrating practical quantum computational advantage with analogue quantum simulators. Owing to the intimate…

For the description of observables and states of a quantum system, it may be convenient to use a canonical Weyl algebra of which only a subalgebra $\mathcal A$, with a non-trivial center $\mathcal Z$, describes observables, the other Weyl…

Mathematical Physics · Physics 2015-11-06 Carlo Heissenberg , Franco Strocchi

We establish an analytical criterion for dynamical thermalization within harmonic systems, applicable to both classical and quantum models. Specifically, we prove that thermalization of various observables, such as particle energies in…

Statistical Mechanics · Physics 2025-07-29 Marco Cattaneo , Marco Baldovin , Dario Lucente , Paolo Muratore-Ginanneschi , Angelo Vulpiani

A local and distributive algorithm is proposed to find an optimal trial wave-function minimizing the Hamiltonian expectation in a quantum system. To this end, the quantum state of the system is connected to the Gibbs state of a classical…

Quantum Physics · Physics 2015-06-03 A. Ramezanpour

We find Weyl upper bounds for the quantum open baker's map in the semiclassical limit. For the number of eigenvalues in an annulus, we derive the asymptotic upper bound $\mathcal O(N^\delta)$ where $\delta$ is the dimension of the trapped…

Spectral Theory · Mathematics 2022-02-23 Zhenhao Li

We introduce a quantum measurement process that is capable of characterizing an unknown state of a system almost without disturbing or collapsing it. The underlying idea is to extract information of a system from the thermodynamic…

Quantum Physics · Physics 2019-11-26 Mohit Lal Bera , Manabendra Nath Bera

We develop a framework for simulating measure-preserving, ergodic dynamical systems on a quantum computer. Our approach provides a new operator-theoretic representation of classical dynamics by combining ergodic theory with quantum…

A quantum system at equilibrium is represented by a corresponding classical system, chosen to reproduce the thermodynamic and structural properties. The objective is to develop a means for exploiting strong coupling classical methods (e.g.,…

Statistical Mechanics · Physics 2015-05-30 James W. Dufty , Sandipan Dutta

Recent progress in the development of quantum technologies has enabled the direct investigation of dynamics of increasingly complex quantum many-body systems. This motivates the study of the complexity of classical algorithms for this…

Quantum Physics · Physics 2023-07-12 Dominik S. Wild , Álvaro M. Alhambra

We show that when the thermal wavelength is comparable to the spatial size of a system, thermodynamic observables like Pressure and Volume have quantum fluctuations that cannot be ignored. They are now represented by operators; conventional…

Statistical Mechanics · Physics 2008-07-30 Antonin Coutant , S. G. Rajeev

In a series of papers we have argued that the 'basic' physical procedure of minimal coupling giving the quantum description of a Hamiltonian system interacting with a magnetic field, can be given a very satisfactory mathematical formulation…

Mathematical Physics · Physics 2018-04-23 Viorel Iftimie , Radu Purice , Marius Mantoiu

Nuclear quantum phenomena beyond the Born-Oppenheimer approximation are known to play an important role in a growing number of chemical and biological processes. While there exists no unique consensus on a rigorous and efficient…

Measuring expectation values of observables is an essential ingredient in variational quantum algorithms. A practical obstacle is the necessity of a large number of measurements for statistical convergence to meet requirements of precision,…

Quantum Physics · Physics 2022-09-07 Masaya Kohda , Ryosuke Imai , Keita Kanno , Kosuke Mitarai , Wataru Mizukami , Yuya O. Nakagawa

A quantum statistical model of nuclear multifragmentation is proposed. The recurrence equation method used within the canonical ensemble makes the model solvable and transparent to physical assumptions and allows to get results without…

Nuclear Theory · Physics 2009-10-31 A. S. Parvan , V. D. Toneev , M. Ploszajczak

Accurate control of quantum systems requires precise measurement of the parameters that govern the dynamics, including control fields and interactions with the environment. Parameters will drift in time and experiments interleave protocols…

Quantum Physics · Physics 2020-02-11 Swarnadeep Majumder , Leonardo Andreta de Castro , Kenneth R. Brown

Quantum simulation has begun to penetrate the field of quantum chemistry in hopes of efficiently calculating ground state energies and approximating real-time evolution. With modern research highlighting nonadiabatic dynamics, tunably…

Quantum Physics · Physics 2026-05-08 Joshua M. Courtney , P. C. Stancil

We present an approach for carrying out non-adiabatic molecular dynamics simulations of systems in which non-adiabatic transitions arise from the coupling between the classical atomic motions and a quasi-continuum of electronic quantum…

Computational Physics · Physics 2018-11-21 Jerome Daligault , Dmitry Mozyrsky