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arXiv 0908.4385cond-mat.mes-hall
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受电报噪声影响的控制寄存器耦合量子比特的部分退相干

Partial decoherence in a qubit coupled to a control register subject to telegraph noise

Amnon Aharony, Ora Entin-Wohlman, Sushanta Dattagupta

摘要:

一个量子比特(包含两个量子态,1和2)耦合到一个控制寄存器(状态3),它受到电报噪声的影响。研究了量子比特上处于相干态的电子的密度矩阵$ρ$的时间演化。在无限时间,$ρ$通常接近完全退相干状态,其中$ρ^{}_{nm}=δ^{}_{nm}/3$。然而,当哈密顿量在$1\leftrightarrow 2$下对称时,元素$ρ^{}_{12}$接近非零实值,这意味着渐近状态的部分相干性。渐近密度矩阵仅依赖于${\rm Re}[ρ^{}_{12}(t=0)]$。在几种情况下,存储在量子位上的信息被保护免受噪声的影响。

英文摘要:

A qubit (containing two quantum states, 1 and 2), is coupled to a control register (state 3), which is subject to telegraph noise. We study the time evolution of the density matrix $ρ$ of an electron which starts in some coherent state on the qubit. At infinite time, $ρ$ usually approaches the fully decoherent state, with $ρ^{}_{nm}=δ^{}_{nm}/3$. However, when the Hamiltonian is symmetric under $1\leftrightarrow 2$, the element $ρ^{}_{12}$ approaches a non-zero real value, implying a partial coherence of the asymptotic state. The asymptotic density matrix depends only on ${\rm Re}[ρ^{}_{12}(t=0)]$. In several cases, the information stored on the qubit is protected from the noise.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

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