We numerically study the effect of the quantum coins on the two-particle quantum walks on an infinite line. Both non-interacting and interacting particles are considered. The joint probability as well as the bunching ...We numerically study the effect of the quantum coins on the two-particle quantum walks on an infinite line. Both non-interacting and interacting particles are considered. The joint probability as well as the bunching or anti- bunching behavior are greatly affected by the phase factors in the coin operation. Further, the spatial correlation can be maximized by choosing appropriate coin parameters. The entanglement between the two particles can be adjusted in the same manner.展开更多
The dynamical and static disordered quantum walks were extensively studied recently. It is found that, for the dynamicM disorder case, the transport behavior of particles is diffusive, and for the static disorder ease...The dynamical and static disordered quantum walks were extensively studied recently. It is found that, for the dynamicM disorder case, the transport behavior of particles is diffusive, and for the static disorder ease the transport behavior is localized. In this work, we study the effect of quantum coins on the transport behaviors of the binary disordered quantum walks. We lind that once the coins satisfy certain conditions, the sub-ballistic spreading could be found in binary dynamical disorder quantum walks, and the sub-ballistic, diffusive and sub- diffusive spreadings could be found in binary static disorder quantum walks. We obtain the necessary conditions for those abnormal diffusive behaviors.展开更多
We investigated discrete-time quantum walks with an arbitary unitary coin.Here we discover that the average position x=max（x） sin（α＋γ）,while the initial state is 1/2～（1/2）（｜0L＋i｜0R）.We verify the result...We investigated discrete-time quantum walks with an arbitary unitary coin.Here we discover that the average position x=max（x） sin（α＋γ）,while the initial state is 1/2～（1/2）（｜0L＋i｜0R）.We verify the result,and obtain some symmetry properties of quantum walks with a U（2） coin with ｜0L and ｜0R as the initial state.展开更多
We study decoherence in the quantum walk on the xy-plane.We generalize the method of decoherent coin quantum walk,introduced by [T.A.Brun,et al.,Phys.Rev.A 67(2003) 032304],which could be applicable to all sorts of de...We study decoherence in the quantum walk on the xy-plane.We generalize the method of decoherent coin quantum walk,introduced by [T.A.Brun,et al.,Phys.Rev.A 67(2003) 032304],which could be applicable to all sorts of decoherence in two-dimensional quantum walks,irrespective of the unitary transformation governing the walk.As an application we study decoherence in the presence of broken line noise in which the quantum walk is governed by the two-dimensional Hadamard operator.展开更多
量子游走是量子计算的重要模型,而多硬币量子游走模型由于在量子通讯协议中表现突出也越来越受到人们的关注.量子相干不仅可以刻画量子态的特点,也可以反映量子演化过程的性质.主要对一维圆上两硬币量子游走模型的量子相干性进行了分析...量子游走是量子计算的重要模型,而多硬币量子游走模型由于在量子通讯协议中表现突出也越来越受到人们的关注.量子相干不仅可以刻画量子态的特点,也可以反映量子演化过程的性质.主要对一维圆上两硬币量子游走模型的量子相干性进行了分析.一方面,讨论了初始量子态和硬币算子的选取对量子相干的影响.当硬币算子为Hadamard算子且初态只要在位置子空间上是均衡叠加态,整个量子游走演化过程是具有周期性的,且量子相干仅依赖于步数和圆上顶点的个数;当初始态是均衡叠加态而对硬币算子没有任何限制时,量子相干的演化也极具规律性.另一方面,发现在利用量子游走实现完美状态转移(perfect state transfer)的过程中,硬币算子的选取直接影响量子相干的值.最后,探讨了2种量子游走模型之间的等价性,并基于此指出了其在量子隐形传输(quantum teleportation)中的应用和改进的可能性.展开更多
基金Supported by the National Natural Science Foundation of China under Grant Nos 11104128,61205119 and 41206084the Natural Science Foundation of Jiangxi-Provincial Office of Education under Grant No GJJ13485the Doctor Start-up Foundation of Nanchang Hangkong University under Grant No EA201008229
文摘We numerically study the effect of the quantum coins on the two-particle quantum walks on an infinite line. Both non-interacting and interacting particles are considered. The joint probability as well as the bunching or anti- bunching behavior are greatly affected by the phase factors in the coin operation. Further, the spatial correlation can be maximized by choosing appropriate coin parameters. The entanglement between the two particles can be adjusted in the same manner.
基金Supported by the National Natural Science Foundation of China under Grant No 11175087the National Basic Research Program of China under Grant No 2009CB929501the Project on Graduate Students’Education and Innovation of Jiangsu Province under Grant No CXZZ13_0392
文摘The dynamical and static disordered quantum walks were extensively studied recently. It is found that, for the dynamicM disorder case, the transport behavior of particles is diffusive, and for the static disorder ease the transport behavior is localized. In this work, we study the effect of quantum coins on the transport behaviors of the binary disordered quantum walks. We lind that once the coins satisfy certain conditions, the sub-ballistic spreading could be found in binary dynamical disorder quantum walks, and the sub-ballistic, diffusive and sub- diffusive spreadings could be found in binary static disorder quantum walks. We obtain the necessary conditions for those abnormal diffusive behaviors.
基金Project supported by the National Natural Science Foundation of China (Grant Nos. 10974192 and 61275122)the National Basic Research Program of China(Grant Nos. 2011CB921200 and 2011CBA00200)K. C. Wong Education Foundation and the Chinese Academy of Sciences
文摘We investigated discrete-time quantum walks with an arbitary unitary coin.Here we discover that the average position x=max（x） sin（α＋γ）,while the initial state is 1/2～（1/2）（｜0L＋i｜0R）.We verify the result,and obtain some symmetry properties of quantum walks with a U（2） coin with ｜0L and ｜0R as the initial state.
文摘We study decoherence in the quantum walk on the xy-plane.We generalize the method of decoherent coin quantum walk,introduced by [T.A.Brun,et al.,Phys.Rev.A 67(2003) 032304],which could be applicable to all sorts of decoherence in two-dimensional quantum walks,irrespective of the unitary transformation governing the walk.As an application we study decoherence in the presence of broken line noise in which the quantum walk is governed by the two-dimensional Hadamard operator.
文摘量子游走是量子计算的重要模型,而多硬币量子游走模型由于在量子通讯协议中表现突出也越来越受到人们的关注.量子相干不仅可以刻画量子态的特点,也可以反映量子演化过程的性质.主要对一维圆上两硬币量子游走模型的量子相干性进行了分析.一方面,讨论了初始量子态和硬币算子的选取对量子相干的影响.当硬币算子为Hadamard算子且初态只要在位置子空间上是均衡叠加态,整个量子游走演化过程是具有周期性的,且量子相干仅依赖于步数和圆上顶点的个数;当初始态是均衡叠加态而对硬币算子没有任何限制时,量子相干的演化也极具规律性.另一方面,发现在利用量子游走实现完美状态转移(perfect state transfer)的过程中,硬币算子的选取直接影响量子相干的值.最后,探讨了2种量子游走模型之间的等价性,并基于此指出了其在量子隐形传输(quantum teleportation)中的应用和改进的可能性.
