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Charge fluctuation induced dephasing of exchange coupled spin qubits

Xuedong Hu·S. Das Sarma
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Abstract

Exchange coupled {\it spin} qubits in semiconductor nanostructures are shown to be vulnerable to dephasing caused by {\it charge noise} invariably present in the semiconductor environment. This decoherence of exchange gate by environmental charge fluctuations arises from the fundamental Coulombic nature of the Heisenberg coupling, and presents a serious challenge to the scalability of the widely studied exchange gate solid state spin quantum computer architectures. We estimate dephasing times for coupled spin qubits in a wide range (from 1 ns up to $> 1 μ$s) depending on the exchange coupling strength and its sensitivity to charge fluctuations.

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Xuedong Hu, S. Das Sarma. 2006-04-12. Charge fluctuation induced dephasing of exchange coupled spin qubits. https://doi.org/10.1103/physrevlett.96.100501

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