Lagmago Kamta G, Starace Anthony F
Department of Physics and Astronomy, The University of Nebraska, 116 Brace Laboratory, Lincoln, Nebraska 68588-0111, USA.
Phys Rev Lett. 2002 Mar 11;88(10):107901. doi: 10.1103/PhysRevLett.88.107901. Epub 2002 Feb 26.
We investigate the entanglement of a two-qubit anisotropic Heisenberg XY chain in thermal equilibrium at temperature T in the presence of an external magnetic field B along the z axis. By means of the combined influences of anisotropic interactions and a magnetic field B, one is able to produce entanglement for any finite T, by adjusting the magnetic field strength. This contrasts with the isotropic interaction or the B = 0 cases, for which there is no entanglement above a critical temperature T(c) that is independent of the external B field.
我们研究了在沿z轴方向存在外磁场B的情况下，处于温度T热平衡状态的两量子比特各向异性海森堡XY链的纠缠情况。借助各向异性相互作用和磁场B的联合影响，通过调整磁场强度，对于任何有限温度T都能够产生纠缠。这与各向同性相互作用或B = 0的情况形成对比，在这些情况下，高于一个与外部B场无关的临界温度T(c)时就不存在纠缠。
