Improving the purity of one‐ and two‐qubit gates

Kohler, Sigmund; Hänggi, Peter

doi:10.1002/prop.200610314

Cited by 7 publications

(4 citation statements)

References 63 publications

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“…This is agree with the result in Ref. [22] that the low frequency driven field is destructive to the coherence of the qubit.…”

Section: Decoherence and Purity Decaysupporting

confidence: 93%

Decoherence and purity of a driven solid-state qubit in Ohmic bath

Liang

2008

Physica E: Low-dimensional Systems and Nanostructures

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In this paper we study the decoherence and purity of a driven solid-state qubit in the Ohmic bath by using the method based on the master equation. At first, instead of solving the master equation we investigate the coefficients of the equation which describe the shift in frequency, diffusive, decoherence, and so on. It is shown that one of the coefficients (we called it decoherence coefficient) is crucial to the decoherence of the qubit in the model. Then we investigate the evolution of the purity of the state in the model. From the analysis of the purity we see that the decoherence time of the qubit decrease with the increase of the amplitude of the driven fields and it is increase with the increase of the frequency of the driven fields.Comment: 9 pages, 8 figure

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“…This is agree with the result in Ref. [22] that the low frequency driven field is destructive to the coherence of the qubit.…”

Section: Decoherence and Purity Decaysupporting

confidence: 93%

Decoherence and purity of a driven solid-state qubit in Ohmic bath

Liang

2008

Physica E: Low-dimensional Systems and Nanostructures

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“…The system under the presence of charge noise can be studied under a Bloch-Redfield type master equation [38][39][40] . For the 1/f noise typically considered in quantum dot systems, the validity of the Markovian approximation inherent in a master equation approach is only warranted for weak coupling.…”

Section: Charge Noisementioning

confidence: 99%

Direct transfer of two-electron quantum states in ac-driven triple quantum dots

2019

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Preparation and transfer of quantum states is a fundamental task in quantum information. We propose a protocol to prepare a state in the left and center quantum dots of a triple dot array and transfer it directly to the center and right dots. Initially the state in the left and center dots is prepared combining the exchange interaction and magnetic field gradients. Once in the desired state, ac gate voltages in the outer dots are switched on, allowing to select a given photoassisted long-range path and to transfer the prepared state directly from one edge to the other with high fidelity. We investigate the effect of charge noise on the protocol and propose a configuration in which the transfer can be performed with high fidelity. Our proposal can be experimentally implemented and is a promising avenue for transferring quantum states between two spatially separated two-level systems.arXiv:1810.06517v2 [cond-mat.mes-hall]

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“…Fidelity is the most important measure of the functionality of a quantum information device, and in this respect it has been subjected to extensive theoretical work [2]. In experiments fidelity is greatly affected not only by eventual decoherence and dissipation due to the coupling with the environment, but also by internal imperfections such as random irregularities and impurities.…”

Section: Introductionmentioning

confidence: 99%

Optimal control of quantum revival

Räsänen

Heller

2013

Eur. Phys. J. B

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Increasing fidelity is the ultimate challenge of quantum information technology. In addition to decoherence and dissipation, fidelity is affected by internal imperfections such as impurities in the system. Here we show that the quality of quantum revival, i.e., periodic recurrence in the time evolution, can be restored almost completely by coupling the distorted system to an external field obtained from quantum optimal control theory. We demonstrate the procedure with wave-packet calculations in both one-and two-dimensional quantum wells, and analyze the required physical characteristics of the control field. Our results generally show that the inherent dynamics of a quantum system can be idealized at an extremely low cost.

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Improving the purity of one‐ and two‐qubit gates

Cited by 7 publications

References 63 publications

Decoherence and purity of a driven solid-state qubit in Ohmic bath

Decoherence and purity of a driven solid-state qubit in Ohmic bath

Direct transfer of two-electron quantum states in ac-driven triple quantum dots

Optimal control of quantum revival

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