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In this report, we study the reduced conditional dynamics of a quantum system in the case of indirect quantum measurement. The detectors microscopic part (pointer) interacts with the measured system (target) and the environment, which…

Quantum Physics · Physics 2013-11-06 George Miroshnichenko , Alexander Trifanov

We consider the problem of decoherence and relaxation of open bosonic quantum systems from a perspective alternative to the standard master equation or quantum trajectories approaches. Our method is based on the dynamics of expectation…

Quantum Physics · Physics 2009-11-13 D. A. R. Dalvit , G. P. Berman , M. Vishik

An explicit solution of the equation for the classical harmonic oscillator with smooth switching of the frequency has been found . A detailed analysis of a quantum harmonic oscillator with such frequency has been done on the base of the…

Quantum Physics · Physics 2007-05-23 A. Angelow

We introduce a method of characterization of non-Markovianity using coherence of a system interacting with the environment. We show that under the allowed incoherent operations, monotonicity of a valid coherence measure is affected due to…

Quantum Physics · Physics 2016-11-28 Titas Chanda , Samyadeb Bhattacharya

Moving detectors in relativistic quantum field theories reveal the fundamental entangled structure of the vacuum which manifests, for instance, through its thermal character when probed by a uniformly accelerated detector. In this paper, we…

Quantum Physics · Physics 2019-08-21 Benjamin Roussel , Alexandre Feller

An extended variational principle providing the equations of motion for a system consisting of interacting classical, quasiclassical and quantum components is presented, and applied to the model of bilinear coupling. The relevant dynamical…

Quantum Physics · Physics 2009-11-13 M. Grigorescu

Variational representations of quantum states abound and have successfully been used to guess ground-state properties of quantum many-body systems. Some are based on partial physical insight (Jastrow, Gutzwiller projected, and fractional…

Quantum Physics · Physics 2019-12-18 Douglas Hendry , Adrian E. Feiguin

In this paper we analyze an exactly solvable model consisting of an inertial Unruh-DeWitt detector which interacts linearly with a massless quantum field in Minkowski spacetime with a perfectly reflecting flat plane boundary. Firstly a set…

Quantum Physics · Physics 2015-06-12 Rong Zhou , Ryan O. Behunin , Shih-Yuin Lin , B. L. Hu

Dynamical aspects of information-theoretic and entropic measures of quantum systems are studied. First, we show that for the time-dependent harmonic oscillator, as well as for the charged particle in certain time-varying electromagnetic…

Quantum Physics · Physics 2022-03-22 K. Andrzejewski

We tackle the dynamical description of the quantum measurement process, by explicitly addressing the interaction between the system under investigation with the measurement apparatus, the latter ultimately considered as macroscopic quantum…

Quantum Physics · Physics 2019-07-31 A. De Pasquale , C. Foti , A. Cuccoli , V. Giovannetti , P. Verrucchi

Using the Ermakov-Lewis invariants appearing in KvN mechanics, the time-dependent frequency harmonic oscillator is studied. The analysis builds upon the operational dynamical model, from which it is possible to infer quantum or classical…

The emergence of classical behaviour in quantum theory is often ascribed to the interaction of a quantum system with its environment, which can be interpreted as environmental monitoring of the system. As a result, off-diagonal elements of…

Quantum Physics · Physics 2025-04-24 Dorje C. Brody , Eva-Maria Graefe , Rishindra Melanathuru

Quantum coherence in curved spacetime offers a fresh window into the interplay between gravity, thermality, and quantum resources. While previous work has shown that Markovian evolution can generate entanglement and other nonclassical…

General Relativity and Quantum Cosmology · Physics 2025-10-06 Samira Elghaayda , Atta ur Rahman , Mostafa Mansour

In this manuscript we provide a consistent way of describing a localized non-relativistic quantum system undergoing a timelike trajectory in a background curved spacetime. Namely, using Fermi normal coordinates, we identify an inner product…

Quantum Physics · Physics 2024-03-08 T. Rick Perche

A system of a quantum harmonic oscillator bi-linearly coupled with a Glauber amplifier is analysed considering a time-dependent Hamiltonian model. The Hilbert space of this system may be exactly subdivided into invariant finite dimensional…

Quantum Physics · Physics 2020-01-29 R. Grimaudo , V. I. Man'ko , M. A. Man'ko , A. Messina

We consider the general open system problem of a charged quantum oscillator confined in a harmonic trap, whose frequency can be arbitrarily modulated in time, that interacts with both an incoherent quantized (blackbody) radiation field and…

Quantum Physics · Physics 2014-01-14 Leonardo A. Pachón , Paul Brumer

The non-commutativity of position and momentum observables is a hallmark feature of quantum physics. However this incompatibility does not extend to observables which are periodic in these base variables. Such modular-variable observables…

Quantum Physics · Physics 2018-04-11 C. Flühmann , V. Negnevitsky , M. Marinelli , J. P. Home

The techniques employed to solve the interaction of a detector and a quantum field typically require perturbation methods. We introduce mathematical techniques to solve the time evolution of an arbitrary number of detectors interacting with…

Quantum Physics · Physics 2014-04-01 David Edward Bruschi , Antony R. Lee , Ivette Fuentes

We develop a detector-based framework in which quantum theory and spacetime geometry arise within a common inferential structure. Detector states and a detector kernel assign amplitudes to measurement events, allowing quantum theory to be…

Quantum Physics · Physics 2026-04-14 Marcello Rotondo

We show that the unitary evolution of a harmonic oscillator coupled to a two-level system can be undone by a suitable manipulation of the two-level system -- more specifically: by a quasi-instantaneous phase change. This enables us to…

Quantum Physics · Physics 2010-03-26 Giovanna Morigi , Enrique Solano , Berthold-Georg Englert , Herbert Walther