Using the quantum Zeno effect for suppression of decoherence

Kondo, Yasushi; Matsuzaki, Yuichiro; Matsushima, Kiyoshi; Filgueiras, Jefferson G.

doi:10.1088/1367-2630/18/1/013033

Cited by 38 publications

(25 citation statements)

References 32 publications

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“…We illustrate our idea to obtain various open systems or to engineer the environment in figure 1 [21,22,26,27], see also [23,24]. If a well-defined quantum system (such as a qubit) shows an exponential relaxation, the system interacts with a surrounding short-time memory (or, Markovian) environment.…”

Section: Engineered Environmentmentioning

confidence: 99%

“…In our previous works [21,27], we employed numerical simulations with the idea of quantum channels in order to evaluate the above models. In this paper, we will start from the Lindblad master equation [28] and solve it analytically [29][30][31].…”

Section: Engineered Environmentmentioning

confidence: 99%

“…We have been realizing an engineered environment and studying methods protecting a system from environment [21,26,27]. Our engineered environment may be regarded as a realization of the pseudomode [23,24] or the extended collision model [25].…”

Section: Introductionmentioning

confidence: 99%

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Realization of controllable open system with NMR

Matsuzaki

et al. 2019

New J. Phys.

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An open quantum system is now attracting much attention because a quantum device such as quantum computers and quantum sensors is an emerging technology. Here, we present a model of the open system that shows either time-homogeneous Markovian relaxations or non-Markovian relaxations depending on its parameters that we can control. This model is fully described with the master equation that is analytically solvable. More importantly, this model can be easily realized with molecules in isotropic liquids and measured with NMR techniques. V 1 1 , J J J J t t J J J t J t t J J J t J

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Section: Engineered Environmentmentioning

confidence: 99%

Section: Engineered Environmentmentioning

confidence: 99%

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Realization of controllable open system with NMR

Matsuzaki

et al. 2019

New J. Phys.

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“…There were a lot of work has been done to suppress these kind of decoherences. Feedback control [9], Quantum Zeno effect [10], weak measurement [11]etc are some methods which has been used to protect qubits ( single as well as entangled ) against decoherence. The measures of entanglement used in these methods are negativity, concurrence, discord etc.…”

Section: Introduction:-mentioning

confidence: 99%

Trace Distance: A Measure of Quantumness.

Bhatt¹

2017

IJAR

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We use trace distance as a measure of quantum character in qubits and have calculated the success probability. When a qubit is subjected to environmental noise particularly amplitude damping noise it is expected that its quantum character is diminishes. In this work we also have used weak measurement and quantum measurement reversal operations for the protection of qubits from decoherence. From this study we found that trace distance is actually a good measure of closeness of two states. . For quantum information science to work properly there are many other things such as qubits, entanglement, discord etc. A qubit as we know that is a basic unit for the communication through any quantum channel. It is a superposition of two states [1]. In information theory its preservation is quite essential. The entanglement between two qubits is one of the special feature of quantum information science. It is frequently used in making many protocols, such as teleportation of unknown states [3].Quantum key distribution [4]quantum cryptography [5,6] and quantum computation [7,8]. The study of open quantum system is also important because environmental noises called, decoherence badly affects the quantum states. Among various kind of noises which can produce decorhence amplitude damping, depolarising, phase damping are so popular [1]. There were a lot of work has been done to suppress these kind of decoherences. Feedback control [9], Quantum Zeno effect [10], weak measurement [11]etc are some methods which has been used to protect qubits ( single as well as entangled ) against decoherence. The measures of entanglement used in these methods are negativity, concurrence, discord etc.[1]. Recently we have described a measure of quantumness called trace distance [1] [12]. We have shown that trace distance can be used as a suitable measure for describing quantum character between two qubit states which we have taken before decoherence and after applying weak measurement.Weak measurement and its reversal also plays an important role for the suppression of decohrence [13]. Now it's important to protect a qubit as well as entangles qubits from decoherence. In this letter we try to show that how trace distance between two qubit states changes with success probability, which is defined as probability of occurrence of decoherence when the qubit is subjected to amplitude damping noise and after that weak measurements . The paper is organized in following manner:

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“…An NMR scheme to preserve a separable state was constructed using the superZeno scheme and the state preservation was found to be more efficient as compared to the standard Zeno scheme [22]. The quantum Zeno effect was used to stabilize superpositions of states of NMR qubits against dephasing, using an ancilla to perform the measurement [23]. Entanglement preservation based on a dynamic quantum Zeno effect was demonstrated using NMR wherein frequent measurements were implemented through entangling the target and measuring qubits [24].…”

Section: Introductionmentioning

confidence: 99%

Experimental protection against evolution of states in a subspace via a super-Zeno scheme on an NMR quantum information processor

2014

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We experimentally demonstrate the freezing of evolution of quantum states in one-and two-dimensional subspaces of two qubits, on an NMR quantum information processor. State evolution was frozen and leakage of the state from its subspace to an orthogonal subspace was successfully prevented using super-Zeno sequences [Phys. Rev. Lett. 96, 100405 (2006)], comprising a set of radio frequency (rf) pulses punctuated by pre-selected time intervals. We demonstrate the efficacy of the scheme by preserving different types of states, including separable and maximally entangled states in one-and two-dimensional subspaces of two qubits. The change in the experimental density matrices was tracked by carrying out full state tomography at several time points. We use the fidelity measure for the one-dimensional case and the leakage (fraction) into the orthogonal subspace for the two-dimensional case, as qualitative indicators to estimate the resemblance of the density matrix at a later time to the initially prepared density matrix. For the case of entangled states, we additionally compute an entanglement parameter to indicate the presence of entanglement in the state at different times. We experimentally demonstrate that the super-Zeno scheme is able to successfully confine state evolution to the one-or two-dimensional subspace being protected.

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Using the quantum Zeno effect for suppression of decoherence

Cited by 38 publications

References 32 publications

Realization of controllable open system with NMR

Realization of controllable open system with NMR

Trace Distance: A Measure of Quantumness.

Experimental protection against evolution of states in a subspace via a super-Zeno scheme on an NMR quantum information processor

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