论文标题
$ xxx $中央旋转模型中纠缠量子状态的纠缠量子状态的破裂动力学
Decoherence dynamics of entangled quantum states in the $XXX$ central spin model
论文作者
论文摘要
在实践中实现大规模的量子计算机，保持量子的连贯性至关重要。在这项工作中，我们研究了$ XXX $中央旋转模型（CSM）中的中央旋转破坏性问题，并专注于具有不同初始纠缠的量子状态，即浴缸内纠缠或系统垫子纠缠。我们通过分析获得他们的忠诚，纠缠和量子连贯性的发展。当最初的浴室旋转构成$ n $零件纠缠状态（Greenberger-Horne-Zeilinger-Bath或$ w $ -bath）时，其富裕发展的领先振幅均为$ \ Mathcal o（1/n）$，与完全极化的浴室相同。但是，当中央旋转与其中一种沐浴旋转最大化时，其保真度演化的幅度缩放从$ \ nathcal o（1/n）$（1/n）$变为$ \ Mathcal o（1/n^2）$。这意味着适当的初始系统托架纠缠是有助于抑制中央自旋脱熔。此外，借助系统浴纠缠，我们意识到中央旋转的量子相干增强动力学，在这种动力上，浴室纠缠的消费被证明起着核心作用。
Maintaining coherence of a qubit is of vital importance for realizing a large-scale quantum computer in practice. In this work, we study the central spin decoherence problem in the $XXX$ central spin model (CSM) and focus on the quantum states with different initial entanglement, namely intra-bath entanglement or system-bath entanglement. We analytically obtain their evolutions of fidelity, entanglement, and quantum coherence. When the initial bath spins constitute an $N$-particle entangled state (the Greenberger-Horne-Zeilinger-bath or the $W$-bath), the leading amplitudes of their fidelity evolutions both scale as $\mathcal O(1/N)$, which is the same as the case of a fully polarized bath. However, when the central spin is maximally entangled with one of the bath spins, the amplitude scaling of its fidelity evolution declines from $\mathcal O(1/N)$ to $\mathcal O(1/N^2)$. That implies appropriate initial system-bath entanglement is contributive to suppress central spin decoherence. In addition, with the help of system-bath entanglement, we realize quantum coherence-enhanced dynamics for the central spin where the consumption of bath entanglement is shown to play a central role.
