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Related papers: Quantum Jarzynski-Sagawa-Ueda relations

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Quantum measurements of physical quantities are usually described as ideal measurements. However, only a few measurements fulfil the conditions of ideal measurements. The aim of the present work is to describe real position measurements…

Quantum Physics · Physics 2019-01-17 Klaus Wick

Quantum mechanics is usually formulated with an implicit assumption that agents who can observe and interact with the world are external to it and have a classical memory. However, there is no accepted way to define the quantum-classical…

The environment surrounding a quantum system can, in effect, monitor some of the systems observables. As a result, the eigenstates of these observables continuously decohere and can behave like classical states.

Quantum Physics · Physics 2007-05-23 Wojciech H. Zurek

Feedback control of quantum mechanical systems must take into account the probabilistic nature of quantum measurement. We formulate quantum feedback control as a problem of stochastic nonlinear control by considering separately a quantum…

Quantum Physics · Physics 2007-05-23 Ramon van Handel , John K. Stockton , Hideo Mabuchi

This work concerns a study of the quantum mechanical extension of the work of Horwitz et al. [1] on the stability of classical Hamiltonian systems by geometrical methods. Simulations are carried out for several important examples, these…

Quantum Physics · Physics 2017-04-12 Gil Elgressy , Lawrence Horwitz

Feedback control of open quantum systems is of fundamental importance for practical applications in various contexts, ranging from quantum computation to quantum error correction and quantum metrology. Its use in the context of…

Physics is a model of nature able to both describe and predict the results of measurements made with respect to reference systems. These reference systems, in turn, are themselves physical and thus subject to the laws of physics. The…

Quantum Physics · Physics 2025-09-05 Henrique A. R. Knopki , Renato M. Angelo

It is widely known that `collapse of the wave function' on a quantum system A may be brought about by an interaction with another quantum system B. We will prove that this is not just a possible, but a necessary consequence of information…

Quantum Physics · Physics 2007-05-23 Bas Janssens

An explicit expression is derived for the statistical description of small quantum systems, which are relatively-weakly and directly coupled to only small parts of their environments. The derived expression has a canonical form, but is…

Quantum Physics · Physics 2015-06-05 Wen-ge Wang

Measuring a quantum system can randomly perturb its state. The strength and nature of this back-action depends on the quantity which is measured. In a partial measurement performed by an ideal apparatus, quantum physics predicts that the…

A universal formulation of the quantum uncertainty regarding quantum indeterminacy, quantum measurement, and its inevitable observer effect is presented with additional focus on the representability of quantum observables over a given…

Quantum Physics · Physics 2022-04-27 Jaeha Lee

In this short communication, I give a very simple derivation of the Jarzynski equality, which allows to compute the free energy difference of a body, which is driven between two equilibrium states $A$ and $B$ by an external (time-dependent)…

Statistical Mechanics · Physics 2016-08-16 Frédéric Douarche

Feedback control is expected to considerably protect quantum states against decoherence caused by interaction between the system and environment. Especially, Markovian feedback scheme developed by Wiseman can modify the properties of…

Quantum Physics · Physics 2007-05-23 Naoki Yamamoto

We consider an ideal experiment in which unlimited nonprojective quantum measurements are sequentially performed on a system that is initially entangled with a distant one. At each step of the sequence, the measurements are randomly chosen…

Quantum Physics · Physics 2018-03-30 Armin Tavakoli , Adán Cabello

A quantum channel physically is a unitary interaction between the information carrying system and an environment, which is initialized in a pure state before the interaction. Conventionally, this state, as also the parameters of the…

Quantum Physics · Physics 2016-10-25 Siddharth Karumanchi , Stefano Mancini , Andreas Winter , Dong Yang

The two-time measurement scheme is well studied in the context of quantum fluctuation theorem. However, it becomes infeasible when the random variable determined by a single measurement trajectory is associated with the von-Neumann entropy…

Quantum Physics · Physics 2023-04-20 Akira Sone , Naoki Yamamoto , Tharon Holdsworth , Prineha Narang

Ever since the advent of quantum mechanics, it has been clear that the atoms composing matter do not obey Newton's laws. Instead, their behavior is described by the Schroedinger equation. Surprisingly though, until recently, no clear…

Quantum Physics · Physics 2007-05-23 Tanmoy Bhattacharya , Salman Habib , Kurt Jacobs

We address the issue of coupling variables which are essentially classical to variables that are quantum. Two approaches are discussed. In the first (based on collaborative work with L.Di\'osi), continuous quantum measurement theory is used…

General Relativity and Quantum Cosmology · Physics 2009-10-31 J. J. Halliwell

We study the dynamics of a quantum system $\Gamma$ with an environment $\Xi$ made of $N$ elementary quantum components. We aim at answering the following questions: can the evolution of $\Gamma$ be characterized by some general features…

Quantum Physics · Physics 2019-08-28 Caterina Foti , Teiko Heinosaari , Sabrina Maniscalco , Paola Verrucchi

Fluctuation relations allow for the computation of equilibrium properties, like free energy, from an ensemble of non-equilibrium dynamics simulations. Computing them for quantum systems, however, can be difficult, as performing dynamic…

Quantum Physics · Physics 2021-09-07 Lindsay Bassman , Katherine Klymko , Diyi Liu , Norman M. Tubman , Wibe A. de Jong