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It is difficult to evaluate the precision of quantum measurements because it is not possible to conduct a second reference measurement on the same physical system to compare the measurement outcome with a more accurate value of the measured…

Quantum Physics · Physics 2021-02-10 Holger F. Hofmann

The dynamical evolution of a quantum register of arbitrary length coupled to an environment of arbitrary coherence length is predicted within a relevant model of decoherence. The results are reported for quantum bits (qubits) coupling…

Quantum Physics · Physics 2009-11-07 John H. Reina , Luis Quiroga , Neil F. Johnson

Quantum states are described by wave functions whose phases cannot be directly measured, but which play a vital role in quantum effects such as interference and entanglement. The loss of the relative phase information, termed decoherence,…

Chemical Physics · Physics 2019-12-20 Jia Chen , Cong Hu , John F. Stanton , Stephen Hill , Hai-Ping Cheng , Xiao-Guang Zhang

A pedagogical and reasonably self-contained introduction to the measurement problems in quantum mechanics and their partial solution by environment-induced decoherence (plus some other important aspects of dcoherence) is given. The point…

Quantum Physics · Physics 2007-05-23 Tulsi Dass

In order to understand quantum decoherence of a quantum system due to its interaction with a large system behaving classically, we introduce the concept of adiabatic quantum entanglement based on the Born-Oppenhemeir approximation. In the…

Quantum Physics · Physics 2019-08-17 C. P. Sun , D. L. Zhou , S. Yu , X. F. Liu

The effects of the measurement apparatus on quantum coherence are studied by considering a purely dephasing model of a qubit. The initial state is prepared from a thermal state of the whole system by performing a nonselective measurement on…

Quantum Physics · Physics 2021-12-22 Filippo Giraldi

The peculiar uncertainty or randomness of quantum measurements stems from coherence, whose information-theoretic characterization is currently under investigation. Under the resource theory of coherence, it is interesting to investigate…

Quantum Physics · Physics 2019-10-25 Xiao Yuan , Qi Zhao , Davide Girolami , Xiongfeng Ma

We investigate how quantum coherence can be distributed among the several off-diagonal elements of an arbitrary density matrix. An easily computable quantity that captures this variability notion is proposed and it is argued that it…

Quantum Physics · Physics 2026-04-24 Fernando Parisio

A quantum system with discrete and continuos evolution spectrum is studied. A final pointer basis is found, that can be defined in a presised mathematical way. This result is use to explain the quantum measurement in the system.

Quantum Physics · Physics 2007-05-23 M. Castagnino , R. Laura , R. Id Betan

We study decoherence in a simple quantum mechanical model using two approaches. Firstly, we follow the conventional approach to decoherence where one is interested in solving the reduced density matrix from the perturbative master equation.…

Quantum Physics · Physics 2015-05-20 Jurjen F. Koksma , Tomislav Prokopec , Michael G. Schmidt

The wide-ranging adoption of quantum technologies requires practical, high-performance advances in our ability to maintain quantum coherence while facing the challenge of state collapse under measurement. Here we use techniques from control…

Quantum Physics · Physics 2017-02-01 Sandeep Mavadia , Virginia Frey , Jarrah Sastrawan , Stephen Dona , Michael J. Biercuk

We propose a novel approach to quantify quantum coherence which, contrary to the previous ones, does not rely on resource theory but rather on ontological considerations. In this framework, coherence is understood as the ability for a…

Mathematical Physics · Physics 2025-02-17 Antoine Soulas

We investigate quantum dynamical systems defined on a finite dimensional Hilbert space and subjected to an interaction with an environment. The rate of decoherence of initially pure states, measured by the increase of their von Neumann…

Quantum Physics · Physics 2009-11-10 Robert Alicki , Artur Lozinski , Prot Pakonski , Karol Zyczkowski

Incompatible, i.e. non-jointly measurable quantum measurements are a necessary resource for many information processing tasks. It is known that increasing the number of distinct measurements usually enhances the incompatibility of a…

Quantum Physics · Physics 2023-09-28 Lucas Tendick , Hermann Kampermann , Dagmar Bruß

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

Quantifying coherence is an essential endeavor for both quantum foundations and quantum technologies. In this paper, we put forward a quantitative measure of coherence by following the axiomatic definition of coherence measures introduced…

Quantum Physics · Physics 2017-07-06 C. L. Liu , Da-Jian Zhang , Xiao-Dong Yu , Qi-Ming Ding , Longjiang Liu

Quantum instruments derived from composite systems allow greater measurement precision than their classical counterparts due to coherences maintained between N components; spins, atoms or photons. Decoherence that plagues real-world devices…

Quantum Physics · Physics 2014-02-04 Sergey I. Knysh , Edward H. Chen , Gabriel A. Durkin

The length of time that a quantum system can exist in a superposition state is determined by how strongly it interacts with its environment. This interaction entangles the quantum state with the inherent fluctuations of the environment. If…

Quantum Physics · Physics 2013-10-15 K. W. Murch , S. J. Weber , C. Macklin , I. Siddiqi

Unwanted interaction between a quantum system and its fluctuating environment leads to decoherence and is the primary obstacle to establishing a scalable quantum information processing architecture. Strategies such as environmental and…

We study decoherence induced by a dynamic environment undergoing a quantum phase transition. Environment's susceptibility to perturbations - and, consequently, efficiency of decoherence - is amplified near a critical point. Over and above…

Quantum Physics · Physics 2013-05-29 Bogdan Damski , H. T. Quan , Wojciech H. Zurek