Decoherence and entanglement dynamics in fluctuating fields

Helm, Julius; Strunz, Walter T.

doi:10.1103/physreva.81.042314

Cited by 23 publications

(21 citation statements)

References 28 publications

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“…In other words, if a pure state is a convex combination of ME states, it will be RU dynamics. Evidently, the Bell state is a part of RU class [4].…”

Section: Random Unitary Channelmentioning

confidence: 99%

“…Decoherence arises as a result of coupling of the desired system and quantum environment. Decoherence is the most important obstacle to use quantum states in larger and larger scale [4]. Phase damping channel is one type of decoherence in which non-diagonal elements of density matrix are altered due to the coupling of the system and environment; however, diagonal elements of density matrix remain unchanged.…”

Section: Introductionmentioning

confidence: 99%

“…These channels can be corrected by classical information of environment [69] and are more important in practical view. For instance, decoherence can be regulated by RU dynamics in nuclear magnetic resonance and quantum computers which are based on trapped ions [2,4].…”

Section: Introductionmentioning

confidence: 99%

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Investigation of a Two-Qubit Decoherence by Using Bloch Vectors

Ahmadi¹,

Jami²

2014

Acta Phys. Pol. A

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The loss of the coherence happens due to the interaction between the desired system and its surroundings. Addressing decoherence is one of the main concepts in the study of quantum channels to access their potential for various scale. In this process the information of the system is penetrated into the environment. Therefore, the measurement of the environment could be used as the error correction method. Phase damping channels principally belong to random unitary channels and can be corrected by classical information. This paper presents a method to generate non-random unitary phase damping channels based on the Bloch vectors in two qubits systems. A phase damping channel which consisted of a two qubits system and a single qubit environment was investigated. The results demonstrated that the phase damping channels belong to random unitary dynamics if the three-dimensional tetrahedron volume spanned by the Bloch vectors in R 3 is not zero, or, the same hyperplane in R 3 was not pointed by the Bloch vectors. It is found that the Bell state belongs to random unitary class and can be corrected based on classical information obtained from environmental measurements.

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“…In other words, if a pure state is a convex combination of ME states, it will be RU dynamics. Evidently, the Bell state is a part of RU class [4].…”

Section: Random Unitary Channelmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Investigation of a Two-Qubit Decoherence by Using Bloch Vectors

Ahmadi¹,

Jami²

2014

Acta Phys. Pol. A

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“…In fact, the latter situation is often realized in real systems, especially in the case of large environments, high temperatures, or noise resulting from e. g. fluctiating semi-classical fields [13][14][15][16]. The distinction between entangling and non-entangling evolutions is not trivial in itself, since the non-entangling case is not limited to random unitary evolutions [1,[17][18][19][20][21], and a straightforward criterion for the generation of qubit-environment entanglement during pure dephasing has only recently been found [3].…”

Section: Introductionmentioning

confidence: 99%

Entanglement generation between a charge qubit and its bosonic environment during pure dephasing: Dependence on the environment size

Salamon

Roszak

2017

Phys. Rev. A

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We study entanglement generated between a charge qubit and a bosonic bath due to their joint evolution which leads to pure dephasing of the qubit. We tune the parameters of the interaction, so that the decoherence is quantitatively independent of the number of bosonic modes taken into account and investigate, how the entanglement generated depends on the size of the environment. A second parameter of interest is the mixedness of the initial state of the environment which is controlled by temperature. We show analytically that for a pure initial state of the environment, entanglement does not depend on environment size. For mixed initial states of the environment, the generated entanglement decreases with the increase of environment size. This effect is stronger for larger temperatures, when the environment is initially more mixed, but in the limit of an infinitely large environment, no entanglement is created at any finite temperature.

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“…For example, in the case of two-qubit system coupled to two local bosonic baths, a Markov environment typically induces both irreversible decoherence and disentanglement [15,16]. However, the non-Markovian environment with a finite memory time can assist in regenerating quantum coherence and entanglement in the system [17][18][19][20]. Some interesting physics induced by a non-Markovian environment has been studied extensively by employing an exact or an approximate non-Markovian master equation, which has many experimental applications in quantum device, quantum information, and quantum optics [21][22][23][24][25].…”

Section: Introductionmentioning

confidence: 99%

Exact non-Markovian master equations for multiple qubit systems: Quantum-trajectory approach

Chen

You

2014

Phys. Rev. A

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A wide class of exact master equations for a multiple qubit system can be explicitly constructed by using the corresponding exact non-Markovian quantum-state diffusion equations. These exact master equations arise naturally from the quantum decoherence dynamics of qubit system as a quantum memory coupled to a collective colored noisy source. The exact master equations are also important in optimal quantum control, quantum dissipation, and quantum thermodynamics. In this paper, we show that the exact non-Markovian master equation for a dissipative N -qubit system can be derived explicitly from the statistical average of the corresponding non-Markovian quantum trajectories. We illustrated our general formulation by an explicit construction of a three-qubit system coupled to a non-Markovian bosonic environment. This multiple qubit master equation offers an accurate time evolution of quantum systems in various domains, and paves the way to investigate the memory effect of an open system in a non-Markovian regime without any approximation.

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Decoherence and entanglement dynamics in fluctuating fields

Cited by 23 publications

References 28 publications

Investigation of a Two-Qubit Decoherence by Using Bloch Vectors

Investigation of a Two-Qubit Decoherence by Using Bloch Vectors

Entanglement generation between a charge qubit and its bosonic environment during pure dephasing: Dependence on the environment size

Exact non-Markovian master equations for multiple qubit systems: Quantum-trajectory approach

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