实现高保真度量子信息传输是量子信息领域的关键任务之一。 基于单比特量子信息在自旋链上的完美传输理论,利用将弱磁场中自旋链体系的哈密顿进行对角化的方法, 分别研究了两种特定磁场情形下,量子信息在长度为N=5的自旋链上传输所受到的影响。 结果表明:空间均匀分布的恒定弱磁场不会对该模型中量子信息的完美传输产生影响; 而对于关于链中心反对称、空间均匀变化的弱磁场而言,完美传输的实现由磁场间隔的大小所决定。 外加磁场越强,实现完美传输的时间越短,磁场越弱所需时间越长。

One of the key tasks in quantum information is to realize quantum information transfer with high fidelity. Based on the theory of perfect transfer of single bit quantum information in spin chain, the influences for quantum information transfer of two kinds of magnetic fields in N = 5 spin chain are studied respectively by the method that Hamiltonian of the system is diagonalized. It is shown that the uniform poor magnetic field does not affect the perfect transfer of quantum information, and for the poor magnetic field with antisymmetry about the chain center and mean variation in space, the condition to realize perfect transfer of quantum information is determined by the magnetic field strength difference. The stronger the magnetic field is, the shorter the time to achieve perfect transmission; the weaker the magnetic field is, the longer it takes.