Bell states of atoms with ultralong lifetimes and their tomographic state analysis.
Bell states of atoms with ultralong lifetimes and their tomographic state analysis.
复制标题
DOI：
10.1103/physrevlett.92.220402
复制
发表时间：
2004-06
影响因子：
8.6
通讯作者：
C. F. Roos;G. Lancaster;M. Riebe;Hartmut Häffner;W. Hänsel;S. Gulde;Christoph Becher;J. Eschner-J.-Esc
中科院分区：
文献类型：
--
作者：
C. F. Roos;G. Lancaster;M. Riebe;Hartmut Häffner;W. Hänsel;S. Gulde;Christoph Becher;J. Eschner-J.-Esc
用确定性和预编程的方法产生了含有两个囚禁离子的任意原子Bell态。使用各种纠缠测量方法对由此产生的纠缠进行了定量分析。为此，我们使用单个量子比特旋转和随后的测量来重建密度矩阵，并具有接近单位的探测效率。这一过程代表了未来量子计算过程层析成像的基本构件。作为第一个应用，详细研究了纠缠的时间衰变。我们观察到Bell态Psi(+/-)的超长寿命，接近亚稳态高量子比特能级自发辐射的基本极限，比所有报道的值长3个数量级。
Arbitrary atomic Bell states with two trapped ions are generated in a deterministic and preprogrammed way. The resulting entanglement is quantitatively analyzed using various measures of entanglement. For this, we reconstruct the density matrix using single qubit rotations and subsequent measurements with near-unity detection efficiency. This procedure represents the basic building block for future process tomography of quantum computations. As a first application, the temporal decay of entanglement is investigated in detail. We observe ultralong lifetimes for the Bell states Psi(+/-), close to the fundamental limit set by the spontaneous emission from the metastable upper qubit level and longer than all reported values by 3 orders of magnitude.