CAJ | 학술논문

在量子通讯的实验中,由于外界环境的影响,我们很难得到最大的纠缠纯态.量子信道可能以混合纠缠态的形式出现.而固体材料中的热平衡态就是一种重要的混合纠缠态.本文利用了两个独立的外加不均匀磁场的一维海森堡链的热纠缠态作为量子信道,实现了两粒子纠缠态的远程传送,分析了外界温度和磁场对纠缠和传输保真度的影响.为了突出传输效果,我们对平均保真度做了研究,结果发现当温度很低,外加反方向的磁场B1和B2时,平均保真度大于经典通道的传输极限值2/3.
재양자통신적실험중,유우외계배경적영향,아문흔난득도최대적규전순태.양자신도가능이혼합규전태적형식출현.이고체재료중적열평형태취시일충중요적혼합규전태.본문이용료량개독립적외가불균균자장적일유해삼보련적열규전태작위양자신도,실현료량입자규전태적원정전송,분석료외계온도화자장대규전화전수보진도적영향.위료돌출전수효과,아문대평균보진도주료연구,결과발현당온도흔저,외가반방향적자장B1화B2시,평균보진도대우경전통도적전수겁한치2/3.
In the experiment of quantum communication, maximal entangled pure states are difficult to got due to the effects of environment. Therefore, a quantum channel is always represented by a form of mixed states. The thermal equilibrium state in solid state materials is one essential mixed entangled state. In this dissertation, a two-particle entangled state can be teleported through the channel of thermal mixed states in two independent 1 D Heisenberg chains. We study the effects of the non-uniform external magnetic field B and temperature T on the entanglement and fidelity. In order to characterize the quality of the teleported state, we make a research of the average fidelity FA. And when B1 and B2 have different directions, the entanglementteleportation is better than the classical teleportation under low temperature. At that case the average fidelity is always larger than 2/3 which is the limited value of the classical teleportation.