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We show that measurement can recover the quantum coherence of a qubit in a non-Markovian environment. The experimental demonstration in an optical system is provided by comparing the visibilities (and fidelities) of the final states with…

Quantum Physics · Physics 2009-11-13 JinShi Xu , ChuanFeng Li , Ming Gong , XuBo Zou , Lei Chen , Geng Chen , JianShun Tang , GuangCan Guo

We study a decoherence reduction scheme that involves an intermediate measurement on the qubit in an equal superposition basis, in the general framework of all qubit-environment interactions that lead to qubit pure decoherence. We show…

Quantum Physics · Physics 2024-02-22 Bartosz Rzepkowski , Katarzyna Roszak

The coupling of a mesoscopic system with its environment usually causes total decoherence: at long times the reduced density matrix of the system evolves in time to a limit which is independent of its initial value, losing all the quantum…

Mesoscale and Nanoscale Physics · Physics 2015-06-05 Amnon Aharony , Shmuel Gurvitz , Yasuhiro Tokura , Ora Entin-Wohlmna , Sushanta Dattagupta

This paper aims to show how adoption of a pragmatist interpretation permits a satisfactory resolution of the quantum measurement problem. The classic measurement problem dissolves once one recognizes that it is not the function of the…

Quantum Physics · Physics 2012-08-01 Richard Healey

Quantum-enhanced measurements use highly non-classical quantum states in order to enhance the precision of the measurement of classical quantities, like the length of an optical cavity. The major goal is to beat the standard quantum limit…

Quantum Physics · Physics 2009-05-29 Daniel Braun , John Martin

Measurement outcomes of a quantum state can be genuinely random (unpredictable) according to the basic laws of quantum mechanics. The Heisenberg-Robertson uncertainty relation puts constrains on the accuracy of two noncommuting observables.…

Quantum Physics · Physics 2017-09-13 Xiao Yuan , Ge Bai , Tianyi Peng , Xiongfeng Ma

We work out an exactly solvable hamiltonian model which retains all the features of realistic quantum measurements. In order to use an interaction process involving a system and an apparatus as a measurement, it is necessary that the…

Quantum Physics · Physics 2009-11-10 Armen E. Allahverdyan , Roger Balian , Theo M. Nieuwenhuizen

The interaction of a quantum system with the environment leads to the so-called quantum decoherence. Beyond its fundamental significance, the understanding and the possible control of this dynamics in various scenarios is a key element for…

Quantum Physics · Physics 2011-09-05 Virginia D'Auria , Noriyuki Lee , Taoufik Amri , Claude Fabre , Julien Laurat

The superposition of quantum states lies at the heart of physics and has been recently found to serve as a versatile resource for quantum information protocols, defining the notion of quantum coherence. In this contribution, we report on…

Quantum Physics · Physics 2019-10-16 Valeria Cimini , Ilaria Gianani , Marco Sbroscia , Jan Sperling , Marco Barbieri

Decoherence phenomena are pervasive in the arena of nanostructures but perhaps even more so in the study of the fundamentals of quantum mechanics and quantum computation. Since there has been little overlap between the studies in both…

Condensed Matter · Physics 2009-11-10 R. F. O'Connell

We present a detailed report on the decoherence of quantum states of continuous variable systems under the action of a quantum optical master equation resulting from the interaction with general Gaussian uncorrelated environments. The rate…

Quantum Physics · Physics 2007-05-23 A. Serafini , M. G. A. Paris , F. Illuminati , S. De Siena

In a close form without referring the time-dependent Hamiltonian to the total system, a consistent approach for quantum measurement is proposed based on Zurek's triple model of quantum decoherence [W.Zurek, Phys. Rev. D 24, 1516 (1981)]. An…

Quantum Physics · Physics 2013-05-29 P. Zhang , X. F. Liu , C. P. Sun

It is proposed that measurement devices can be modelled to have an open decoherence dynamics that is faster than any other relevant timescale, which is referred to as the ultradecoherence limit. In this limit, the measurement device always…

Quantum Physics · Physics 2025-06-09 Hai-Chau Nguyen

The partial trace operation is usually considered in composite quantum systems, to reduce the state on a single subsystem. This operation has a key role in the decoherence effect and quantum measurements. However, partial trace operations…

Quantum Physics · Physics 2024-03-18 Quentin Ansel

It has been claimed that decoherence of open quantum systems explains the tendency of macroscopic systems to exhibit quasiclassical behavior. We show that quasiclassicality is in fact an unremarkable property, characterizing generic…

Quantum Physics · Physics 2009-06-25 Steven Weinstein

We employ the theoretical framework of positive operator valued measures, to study Markovian open quantum systems. In particular, we discuss how a quantum system influences its environment. Using the theory of indirect measurements, we then…

Quantum Physics · Physics 2010-09-23 Ingo Kamleitner

We show that probabilities of results of all possible measurements performing on a quantum system depend on the system's state only through its density matrix. Therefore all experimentally available information about the state contains in…

Quantum Physics · Physics 2016-02-01 Alexey Nenashev

This paper discusses work developed in recent years, in the domain of quantum optics, which has led to a better understanding of the classical limit of quantum mechanics. New techniques have been proposed, and experimentally demonstrated,…

Quantum Physics · Physics 2015-06-26 Luiz Davidovich

Quantum coherence is the key resource for quantum technology, with applications in quantum optics, information processing, metrology and cryptography. Yet, there is no universally efficient method for quantifying coherence either in…

Quantum Physics · Physics 2014-10-24 Davide Girolami

We compare approaches to evaluation of decoherence at low temperatures in two-state quantum systems weakly coupled to the environment. By analyzing an exactly solvable model, we demonstrate that a non-Markovian approximation scheme yields…

Mesoscale and Nanoscale Physics · Physics 2010-10-12 Dmitry Solenov , Vladimir Privman