Quantum quenches of ion Coulomb crystals across structural instabilities
Quantum quenches of ion Coulomb crystals across structural instabilities
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离子库仑晶体跨越结构不稳定性的量子淬灭
DOI：
10.1103/physreva.86.032104
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发表时间：
2012
影响因子：
2.9
通讯作者：
G. Morigi
中科院分区：
文献类型：
--
作者：
Jens D. Baltrusch;C. Cormick;G. Morigi
离子链中的猝灭可以在线性-之字形结构转变中产生运动态的相干叠加。该过程已在[Phys.Rev.A84,063821(2011年)]，并利用自旋依赖力，使得一个离子的电子态的相干叠加演变成链的内部和外部自由度之间的纠缠态。用拉姆齐干涉法对链上一个离子的晶态性质进行了理论研究。对于任意数目的离子链，并且作为猝灭后经过的时间的函数，获得了干涉测量的可见度的解析表达式。能见度非常接近线性之字形不稳定性，衰减非常快，但在驱动结构不稳定性的模式振荡周期表现出回升。这些复苏具有与晶体大小无关的周期性，它们发出了量子猝灭产生纠缠的信号。
Quenches in an ion chain can create coherent superpositions of motional states across the linear-zigzag structural transition. The procedure has been described in [Phys. Rev. A 84, 063821 (2011)] and makes use of spin-dependent forces, so that a coherent superposition of the electronic states of one ion evolves into an entangled state between the chain's internal and external degrees of freedom. The properties of the crystalline state so generated are theoretically studied by means of Ramsey interferometry on one ion of the chain. An analytical expression for the visibility of the interferometric measurement is obtained for a chain of arbitrary number of ions and as a function of the time elapsed after the quench. Sufficiently close to the linear-zigzag instability the visibility decays very fast, but exhibits revivals at the period of oscillation of the mode that drives the structural instability. These revivals have a periodicity that is independent of the crystal size, and they signal the creation of entanglement by the quantum quench.