Balance Between Information Gain and Reversibility in Weak Measurement

Cheong, Yong Wook; Lee, Seung-Woo

doi:10.1103/physrevlett.109.150402

Cited by 88 publications

(85 citation statements)

References 39 publications

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“…Many schemes have been put forward to achieve this purpose, including dynamical decoupling [3][4][5], decoherence free subspaces [6][7][8], quantum error correction code [9][10][11], environment-assisted error correction scheme [12,13], quantum Zeno dynamics [14,15], etc. A novel idea for protecting quantum states by weak measurement and measurement reversal has been proposed theoretically [16,17], and it has been experimentally implemented in the last few years [18][19][20]. The researches focus on the fidelity and quantum entanglement of a quantum system protected by weak measurement and measurement reversal under decoherence [21][22][23][24].…”

Section: Introductionmentioning

confidence: 99%

Enhancement of quantum correlations between two particles under decoherence in finite-temperature environment

Doustimotlagh¹,

Wang²,

You³

et al. 2014

EPL

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Enhancing the quantum correlations in realistic quantum systems interacting with the environment of finite temperature is an important subject in quantum information processing. In this paper, we use weak measurement and measurement reversal to enhance the quantum correlations in a quantum system consisting of two particles. The transitions of the quantum correlations measured by the local quantum uncertainty of qubit-qubit and qutritqutrit quantum systems under generalized amplitude damping channels are investigated. We show that, after the weak measurement and measurement reversal, the joint system shows more robustness against decoherence.

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Section: Introductionmentioning

confidence: 99%

Enhancement of quantum correlations between two particles under decoherence in finite-temperature environment

Doustimotlagh¹,

Wang²,

You³

et al. 2014

EPL

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show abstract

“…The general conclusion of the tradeoff between information gain and reversibility in weak measurement was proved in Ref. [19], which is one of distinct features of weak measurement. We calculate the average fidelityF opt and success probability P We also numerically calculate the average fidelityF opt for some spin length N L with the WM and QMR for fixed p 1 = 0.2 and p 1 = 0.99 and without control in Table I.…”

Section: Introductionmentioning

confidence: 96%

Robust state transfer in the quantum spin channel via weak measurement and quantum measurement reversal

Yao

Zou

2013

Phys. Rev. A

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Using the weak measurement (WM) and quantum measurement reversal (QMR) approach, robust state transfer and entanglement distribution can be realized in the spin-1 2 Heisenberg chain. We find that the ultrahigh fidelity and long distance of quantum state transfer with certain success probability can be obtained using proper WM and QMR, i.e., the average fidelity of a general pure state from 80% to almost 100%, which is almost size independent. We also find that the distance and quality of entanglement distribution for the Bell state and the general Werner mixed state can be obviously improved by the WM and QMR approach.Introduction. Recently, it was shown that weak measurement (WM) and quantum measurement reversal (QMR) can effectively suppress amplitude-damping decoherence for a single qubit [1-3]. In particular, weak measurements and reversal can greatly suppress the disentanglement dynamics of two qubits interacting with their own independent reservoirs [4-6]. More interestingly, the famous entanglement sudden death (ESD) [7] can be avoided by the WM and QMR [5]. Now the WM and QMR also have been widely applied to various aspects of quantum information processing. In Ref.[8], the authors used the WM and QMR to generate the concurrence of assistance from tripartite to bipartite entanglement. In Ref.[9], the authors investigated entanglement amplification via local weak measurements. In Ref.[10], the authors discussed the improvement the fidelity of teleportation through noisy channels using weak measurement and they utilized the standard state teleportation scheme, namely a pair of maximally entangled states serving as state transfer channel. Most of the abovementioned concerns are focused on the model of the qubit system interacting with the reservoir.On the other hand, it is well known that quantum communication based on quantum spin chain has been first addressed in the seminal Ref. [11]. The author demonstrated that the quantum spin chain can be used as a channel for short-distance quantum communication. Then several methods and models of a perfect state transfer were suggested [12,13]. The longdistance state transfer is always an essential task in quantum information processing. We have not seen any report for the application of the WM and QMR in the quantum spin chain model.In this Brief Report, we explore the WM and QMR approach to enhance state transfer and entanglement distribution in the spin-1 2 Heisenberg chain channel. By investigation, using the WM and QMR we find that the lowest and highest average fidelityF of the general pure state through the spin chain channel can attain 80% and close to 100%. More especially, we find that the optimal state transfer is almost size independent. Then we investigate the entanglement distributions of the Bell state and the Werner-mixed state in the spin chain channel and find that the distance and quality of entanglement distribution can obviously improved. In comparison with the scheme of

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“…We present a special class of POVMs that can cause the recurrence of the original state of the quantum system upon repeated measurements. This phenomenon is known as measurement reversal [11][12][13][14][15][16][17][18], where the partially collapsed state of the quantum system (after an unsharp measurement) is reversed back to the original state by performing additional unsharp measurements on it. Measurement reversal has been seen in a number of experiments, both in optical systems as well as in superconducting qubits [19][20][21][22][23].…”

Section: Introductionmentioning

confidence: 99%

How measurement reversal could erroneously suggest the capability to discriminate the preparation basis of a quantum ensemble

Goyal¹,

Singh²,

Ghosh³

2016

Phys. Rev. A

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Mixed states of a quantum system, represented by density operators, can be decomposed as a statistical mixture of pure states in a number of ways where each decomposition can be viewed as a different preparation recipe. However the fact that the density matrix contains full information about the ensemble makes it impossible to estimate the preparation basis for the quantum system. Here we present a measurement scheme to (seemingly) improve the performance of unsharp measurements. We argue that in some situations this scheme is capable of providing statistics from a single copy of the quantum system, thus making it possible to perform state tomography from a single copy. One of the byproduct of the scheme is a way to distinguish between different preparation methods used to prepare the state of the quantum system. However, our numerical simulations disagree with our intuitive predictions. We show that a counter-intuitive property of a biased classical random walk is responsible for the proposed mechanism not working.

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Balance Between Information Gain and Reversibility in Weak Measurement

Cited by 88 publications

References 39 publications

Enhancement of quantum correlations between two particles under decoherence in finite-temperature environment

Enhancement of quantum correlations between two particles under decoherence in finite-temperature environment

Robust state transfer in the quantum spin channel via weak measurement and quantum measurement reversal

How measurement reversal could erroneously suggest the capability to discriminate the preparation basis of a quantum ensemble

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