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We formally extend the notion of Markov order to open quantum processes by accounting for the instruments used to probe the system of interest at different times. Our description recovers the classical Markov order property in the…

Quantum Physics · Physics 2019-04-11 Philip Taranto , Felix A. Pollock , Simon Milz , Marco Tomamichel , Kavan Modi

We investigate what can be concluded about a quantum system when sequential quantum measurements of its observable -- a prominent example of the so-called quantum stochastic process -- fulfill the Kolmogorov consistency condition and thus…

Quantum Physics · Physics 2024-07-02 Piotr Szańkowski , Łukasz Cywiński

We show that stochastic processes with linear conditional expectations and quadratic conditional variances are Markov, and their transition probabilities are related to a three-parameter family of orthogonal polynomials which generalize the…

Probability · Mathematics 2007-05-23 Wlodzimierz Bryc , Jacek Wesolowski

Given a physical quantum system described by a Hilbert H, for any bounded quantum observable (a bounded self-adjoint operator) T it is possible to define several ''hidden observable'' functions f:H->R associated to T and for any quantum…

Quantum Physics · Physics 2007-11-18 Antonio Cassa

We derive a thermodynamic uncertainty relation for general open quantum dynamics, described by a joint unitary evolution on a composite system comprising a system and an environment. By measuring the environmental state after the…

Statistical Mechanics · Physics 2021-01-06 Yoshihiko Hasegawa

It is common, when dealing with quantum processes involving a subsystem of a much larger composite closed system, to treat them as effectively memory-less (Markovian). While open systems theory tells us that non-Markovian processes should…

Quantum Physics · Physics 2019-05-02 Pedro Figueroa-Romero , Kavan Modi , Felix A. Pollock

The study of Markov models is central to control theory and machine learning. A quantum analogue of partially observable Markov decision process was studied in (Barry, Barry, and Aaronson, Phys. Rev. A, 90, 2014). It was proved that…

Quantum Physics · Physics 2019-11-06 Christino Tamon , Weichen Xie

Sublinear expectations for uncertain processes have received a lot of attention recently, particularly methods to extend a downward-continuous sublinear expectation on the bounded finitary functions to one on the non-finitary functions. In…

Probability · Mathematics 2023-05-05 Alexander Erreygers

We consider the issue of non-Markovianity of a quantum dynamics starting from a comparison with the classical definition of Markovian process. We point to the fact that two sufficient but not necessary signatures of non-Markovianity of a…

Quantum Physics · Physics 2015-06-05 Bassano Vacchini

The problem of constructing a consistent quantum-classical hybrid dynamics is afforded in the case of a quantum component in a separable Hilbert space and a continuous, finite-dimensional classical component. In the Markovian case, the…

Quantum Physics · Physics 2023-11-21 Alberto Barchielli

Quantum theory can be viewed as a generalization of classical probability theory, but the analogy as it has been developed so far is not complete. Whereas the manner in which inferences are made in classical probability theory is…

Quantum Physics · Physics 2013-12-04 M. S. Leifer , R. W. Spekkens

In the case of a quantum-classical hybrid system with a finite number of degrees of freedom, the problem of characterizing the most general dynamical semigroup is solved, under the restriction of being quasi-free. This is a generalization…

Quantum Physics · Physics 2026-05-05 Alberto Barchielli , Reinhard Werner

The aim of this paper is to analyze the reconstructability of quantum mechanics from classical conditional probabilities representing measurement outcomes conditioned on measurement choices. We will investigate how the quantum mechanical…

Quantum Physics · Physics 2019-06-13 Gábor Hofer-Szabó

In operator algebra theory, a conditional expectation is usually assumed to be a projection map onto a sub-algebra. In the paper, a further type of conditional expectation and an extension of the Lueders - von Neumann measurement to…

Mathematical Physics · Physics 2010-01-22 Gerd Niestegge

We show that if a product system comes from a quantum Markov semigroup, then it carries a natural Borel structure with respect to which the semigroup may be realized in terms of a measurable representation. We show, too, that the dual…

Operator Algebras · Mathematics 2007-05-23 Paul S. Muhly , Baruch Solel

For the classical mind, quantum mechanics is boggling enough; nevertheless more bizarre behavior could be imagined, thereby concentrating on propositional structures (empirical logics) that transcend the quantum domain. One can also…

Quantum Physics · Physics 2017-01-09 Karl Svozil

A characteristical property of a classical physical theory is that the observables are real functions taking an exact outcome on every (pure) state; in a quantum theory, at the contrary, a given observable on a given state can take several…

Quantum Physics · Physics 2015-06-26 Antonio Cassa

Using a newly introduced connection between the local and non-local description of open quantum system dynamics, we investigate the relationship between these two characterisations in the case of quantum semi-Markov processes. This class of…

Quantum Physics · Physics 2020-08-24 Nina Megier , Andrea Smirne , Bassano Vacchini

We enhance the standard formalism of quantum theory to enable events. The concepts of experiment and of measurement are defined. Dynamics is given by Liouville's equation that couples quantum system to a classical one. It implies a unique…

Quantum Physics · Physics 2009-10-28 Ph. Blanchard , A. Jadczyk

According to a standard view, quantum mechanics (QM) is a contextual theory and quantum probability does not satisfy Kolmogorov's axioms. We show, by considering the macroscopic contexts associated with measurement procedures and the…

Quantum Physics · Physics 2019-05-24 Claudio Garola