N=4自旋链上量子信息在弱磁场中的传输研究

Quantum information transfer in spin chain with N=4 in low-intensity magnetic field

基于量子信息在自旋链上的传输理论,研究了两种磁场情形下N=4的自旋链上单比特量子信息传输受到的影响.对置于磁场中的自旋链,将体系的哈密顿算符进行对角化,进而考虑磁场中信息传输的动力学行为.结果表明空间均匀、时间恒定的弱磁场不会对该模型中量子信息的传输产生任何影响;各格点处大小逐差为B、方向关于链中心对称的弱磁场对量子信息的传输有至关重要的作用.尤其是对于保真度为1的完美传输,磁场参量B很大程度上决定了传输得以实现的条件.

Based on the theory of quantum information transfer in spin chain, the effects of two types of magnetic field are investigated for a single qubit information transfer in spin chain with N= 4. For the spin chain in magnetic fields, Hamiltonian of the system is diagonalized,and the dynamic behavior of information transfer is considered in magnetic field. Results show that the low-intensity magnetic field which is uniform in space and constant in time has nothing to do with quantum information transfer.The low-intensity magnetic field with the difference value B between the nearest-neighbor lattices and the symmetrical direction to center of the spin chain plays a key role for quantum information transfer.Particularly, for the perfect transfer with fidelity value of 1, the transferring condition is dependent on the magnetic parameter B to a great extent.