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We analyze the production of entropy along non-equilibrium processes in quantum systems coupled to generic environments. First, we show that the entropy production due to final measurements and the loss of correlations obeys a fluctuation…

Quantum Physics · Physics 2018-08-08 Gonzalo Manzano , Jordan M. Horowitz , Juan M. R. Parrondo

Controllable adiabatic evolution of a multi-qubit system can be used for adiabatic quantum computation (AQC). This evolution ends at a configuration where the Hamiltonian of the system encodes the solution of the problem to be solved. As a…

In part I, we presented the ring-polymer instanton with explicit friction (RPI-EF) method and showed how it can be connected to the \textit{ab initio} electronic friction formalism. This framework allows the calculation of tunneling…

Chemical Physics · Physics 2022-05-17 Y. Litman , E. S. Pós , C. L. Box , R. Martinazzo , R. J. Maurer , M. Rossi

Collective spin systems -- spin ensembles coupled to a common reservoir and effectively described by a single macrospin -- play an important role in both atomic and solid-state physics. Their intrinsic nonlinearity gives rise to multiple…

Quantum Physics · Physics 2026-04-17 Krzysztof Ptaszynski , Maciej Chudak , Massimiliano Esposito

We shall revisit the conventional adiabatic or Markov approximation, which --contrary to the semiclassical case-- does not preserve the positive-definite character of the corresponding density matrix, thus leading to highly non-physical…

Quantum Physics · Physics 2015-05-13 David Taj , Rita Claudia Iotti , Fausto Rossi

Canonical instanton theory is known to overestimate the rate constant close to a system-dependent crossover temperature and is inapplicable above that temperature. We compare the accuracy of the reaction rate constants calculated using…

Chemical Physics · Physics 2020-09-15 Sean McConnell , Johannes Kästner

The average time $T$ required for high-fidelity readout of quantum states can be significantly reduced via a real-time adaptive decision rule. An adaptive decision rule stops the readout as soon as a desired level of confidence has been…

Quantum Physics · Physics 2016-02-25 B. D'Anjou , L. Kuret , L. Childress , W. A. Coish

Adiabatic quantum optimization has been proposed as a route to solve NP-complete problems, with a possible quantum speedup compared to classical algorithms. However, the precise role of quantum effects, such as entanglement, in these…

Quantum Gases · Physics 2015-06-23 Philipp Hauke , Lars Bonnes , Markus Heyl , Wolfgang Lechner

In the modelling of stochastic phenomena, such as quasi-reaction systems, parameter estimation of kinetic rates can be challenging, particularly when the time gap between consecutive measurements is large. Local linear approximation…

Methodology · Statistics 2026-03-10 Matteo Framba , Veronica Vinciotti , Ernst C. Wit

Steepest-Entropy-Ascent Quantum Thermodynamics (SEAQT) provides a general framework for the description of non-equilibrium phenomena at any level, particularly the atomistic one. This theory and its dynamical postulate are used here to…

Chemical Physics · Physics 2017-05-03 Gian Paolo Beretta , Michael von Spakovsky

We introduce an efficient, quasideterministic scheme to generate maximally entangled states of two atomic ensembles. The scheme is based on quantum nondemolition measurements of total atomic populations and on adiabatic quantum feedback…

Quantum Physics · Physics 2016-09-08 Antonio Di Lisi , Silvio De Siena , Fabrizio Illuminati , David Vitali

We present a new approach to study the thermodynamic properties of $d$-dimensional classical systems by reducing the problem to the computation of ground state properties of a $d$-dimensional quantum model. This classical-to-quantum mapping…

Quantum Physics · Physics 2009-11-13 Rolando D. Somma , Cristian D. Batista , Gerardo Ortiz

The authors present a relativistic and cross-section factorized framework for computing quasielastic A(p,pN) observables at intermediate and high energies. The model is based on the eikonal approximation and can accomodate both optical…

Nuclear Theory · Physics 2007-05-23 B. Van Overmeire , W. Cosyn , P. Lava , J. Ryckebusch

Many problems of industrial interest are NP-complete, and quickly exhaust resources of computational devices with increasing input sizes. Quantum annealers (QA) are physical devices that aim at this class of problems by exploiting quantum…

The evolution of a system of chemical reactions can be studied, in the eikonal approximation, by means of a Hamiltonian dynamical system. The fixed points of this dynamical system represent the different states in which the chemical system…

Statistical Mechanics · Physics 2009-11-13 Carlos Escudero , Jose Angel Rodriguez

We show that quantum nondemolition (QND) measurements can be used to realize measurement-based imaginary time evolution. In our proposed scheme, repeated weak QND measurements are used to estimate the energy of a given Hamiltonian. Based on…

The adiabatic theorem provides sufficient conditions for the time needed to prepare a target ground state. While it is possible to prepare a target state much faster with more general quantum annealing protocols, rigorous results beyond the…

Quantum Physics · Physics 2023-11-28 Luis Pedro García-Pintos , Lucas T. Brady , Jacob Bringewatt , Yi-Kai Liu

The training of neural networks (NNs) is a computationally intensive task requiring significant time and resources. This paper presents a novel approach to NN training using Adiabatic Quantum Computing (AQC), a paradigm that leverages the…

Quantum Physics · Physics 2023-08-28 Steve Abel , Juan Carlos Criado , Michael Spannowsky

In this paper,we present a rigorous demonstration and discussion of the quantum adiabatic theorem for systems having a non degenerate continuous spectrum. A new strategy is initiated by defining a kind of gap, "a virtual gap", for the…

Quantum Physics · Physics 2008-04-28 M. Maamache , Y. Saadi

Nonadiabatic holonomic quantum computation has been proposed as a method to implement quantum logic gates with robustness comparable to that of adiabatic holonomic gates but with shorter execution times. In this paper, we establish an…

Quantum Physics · Physics 2024-06-26 Ole Sönnerborn