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Quantum state estimation for continuously monitored dynamical systems involves assigning a quantum state to an individual system at some time, conditioned on the results of continuous observations. The quality of the estimation depends on…

Quantum Physics · Physics 2022-05-26 Areeya Chantasri , Ivonne Guevara , Kiarn T. Laverick , Howard M. Wiseman

The paper reviews positive and negative time delays in various processes of classical and quantum physics. In the beginning, we demonstrate how a time-shifted response of a system to an external perturbation appears in classical mechanics…

Nuclear Theory · Physics 2015-06-12 E. E. Kolomeitsev , D. N. Voskresensky

The model of weak measurements is applied to various problems, related to the time problem in quantum mechanics. The review and generalization of the theoretical analysis of the time problem in quantum mechanics based on the concept of weak…

Quantum Physics · Physics 2015-06-26 J. Ruseckas , B. Kaulakys

Recent progress in electro-optic sampling has allowed direct access to the fluctuations of the electromagnetic ground state. Here, we present a theoretical formalism that allows for an in-depth characterisation and interpretation of such…

Quantum Physics · Physics 2020-10-28 Frieder Lindel , Robert Bennett , Stefan Yoshi Buhmann

Quantum theory depends on an external classical time, and there ought to exist an equivalent reformulation of the theory which does not depend on such a time. The demand for the existence of such a reformulation suggests that quantum theory…

Quantum Physics · Physics 2012-10-31 Tejinder P. Singh

The method of restricted path integrals allows one to effectively consider continuous (prolonged in time) measurements of quantum systems. Monitoring of the system coordinates is such a continuous measurement that allows one to describe a…

chao-dyn · Physics 2008-02-03 Michael Mensky

It is hypothesized that the Langevin time of stochastic quantum quantization is a physical time over which quantum fields at all values of space and coordinate time fluctuate. The average over paths becomes a time average as opposed to an…

Quantum Physics · Physics 2017-08-16 Michael Grady

We show that applying feedback and weak measurements to a quantum system induces phase transitions beyond the dissipative ones. Feedback enables controlling essentially quantum properties of the transition, i.e., its critical exponent, as…

Quantum Physics · Physics 2020-01-08 D. A. Ivanov , T. Yu. Ivanova , S. F. Caballero-Benitez , I. B. Mekhov

We propose an effective field theory describing the time dependent fluctuations of electrons in conducting systems, generalizing the well known kinetic theory of fluctuations. On several examples, we show its equivalence, (when quantum…

Mesoscale and Nanoscale Physics · Physics 2009-03-22 D. B. Gutman , A. D. Mirlin , Yuval Gefen

Quantum mechanics rests on the assumption that time is a classical variable. As such, classical time is assumed to be measurable with infinite accuracy. However, all real clocks are subject to quantum fluctuations, which leads to the…

General Relativity and Quantum Cosmology · Physics 2008-11-26 J. M. Isidro , J. L. Gonzalez-Santander , P. Fernandez de Cordoba

The quantum theory of indirect measurements in physical systems is studied. The example of an indirect measurement of an observable represented by a self-adjoint operator $\mathcal{N}$ with finite spectrum is analysed in detail. The…

Mathematical Physics · Physics 2017-09-12 M. Ballesteros , N. Crawford , M. Fraas , J. Fröhlich , B. Schubnel

We develop the statistical mechanics of the Hopfield model in a transverse field to investigate how quantum fluctuations affect the macroscopic behavior of neural networks. When the number of embedded patterns is finite, the Trotter…

Condensed Matter · Physics 2009-10-28 Hidetoshi Nishimori , Yoshihiko Nonomura

In this work, we extend the idea of Quantum Markov chains [S. Gudder. Quantum Markov chains. J. Math. Phys., 49(7), 2008] in order to propose Quantum Hidden Markov Models (QHMMs). For that, we use the notions of Transition Operation…

Quantum Physics · Physics 2017-03-03 Michał Cholewa , Piotr Gawron , Przemysław Głomb , Dariusz Kurzyk

We consider an extension of Discrete Time Markov Chain queueing model to the quantum domain by use of Discrete Time Quantum Markov Chain. We introduce methods for numerical analysis of such models. Using this tools we show that quantum…

Quantum Physics · Physics 2013-06-26 Piotr Gawron , Dariusz Kurzyk , Zbigniew Puchała

We review recent progress in attaining a quantitative understanding of the scarring phenomenon, the non-random behavior of quantum wavefunctions near unstable periodic orbits of a classically chaotic system. The wavepacket dynamics…

chao-dyn · Physics 2009-08-14 L. Kaplan

Perturbation theory in quantum mechanics studies how quantum systems interact with their environmental perturbations. Harmonic perturbation is a rare special case of time-dependent perturbations in which exact analysis exists. Some…

Quantum Physics · Physics 2008-01-01 Jie-Hong R. Jiang , Dah-Wei Chiou , Cheng-En Wu

Motivated by applications in movement ecology, in this paper I propose a new class of integrated continuous-time hidden Markov models in which each observation depends on the underlying state of the process over the whole interval since the…

Methodology · Statistics 2019-10-01 Paul G Blackwell

A quantum trajectory describes the evolution of a quantum system undergoing indirect measurement. In the discrete-time setting, the state of the system is updated by applying Kraus operators according to the measurement results. From an…

Quantum Physics · Physics 2022-04-04 Maël Bompais , Nina H. Amini , Clément Pellegrini

A fundamental prediction of quantum theory that is derived from the "projection postulate" is that under continuous measurement, the state of a system traces out a "quantum trajectory" in time that depends upon its measurement record, and…

Quantum Physics · Physics 2014-01-03 A. A. Gangat

Hidden-variable models aim to reproduce the results of quantum theory and to satisfy our classical intuition. Their refutation is usually based on deriving predictions that are different from those of quantum mechanics. Here instead we…

Quantum Physics · Physics 2015-03-05 Radu Ionicioiu , Robert B. Mann , Daniel R. Terno