Using the tensor renormalization group method based on the higher-order singular value decomposition, we have studied the phase transitions of the five-state clock model on the square lattice. The temperature dependen...Using the tensor renormalization group method based on the higher-order singular value decomposition, we have studied the phase transitions of the five-state clock model on the square lattice. The temperature dependence of the specific heat indicates the system has two phase transitions, as verified clearly by the correlation function at three representative tem- peratures. By calculating the magnetic susceptibility, we obtained only the upper critical temperature as To2 = 0.9565（7）. Investigating the fixed-point tensor, we precisely locate the transition temperatures at Tcl = 0.9029（1） and Tc2 = 0.9520（1）, consistent well with the Monte Carlo and the density matrix renormalization group results.展开更多
A scheme for controlled quantum state swapping is presented using maximally entangled five-qubit state,i.e.,Alice wants to transmit an entangled state of particle a to Bob and at the same time Bob wants to transmit an...A scheme for controlled quantum state swapping is presented using maximally entangled five-qubit state,i.e.,Alice wants to transmit an entangled state of particle a to Bob and at the same time Bob wants to transmit an entangled state of particle b to Alice via the control of the supervisor Charlie.The operations used in this swapping process including C-not operation and a series of single-qubit measurements performed by Alice,Bob,and Charlie.展开更多
A scheme for probabilistic teleportation of an unknown three-atom entangled state via a five-atom non- maximally entangled cluster state as quantum channel is proposed. In this scheme, the sender performs two Bell sta...A scheme for probabilistic teleportation of an unknown three-atom entangled state via a five-atom non- maximally entangled cluster state as quantum channel is proposed. In this scheme, the sender performs two Bell state and a single-atom measurements on the atoms, the receiver can reconstruct the original state with a certain probability by introducing an auxiliary atom and operating appropriate unitary transformations and controlled-not （C-not） operations according to the sender Alice＇s measurement results. As a result, the probability of successful teleportation is determined by the smallest two of the coefficients＇ absolute values of the cluster state. The considerable advantage of our scheme is that we employ a non-maximally entangled cluster state as quantum channel in the scheme, which can greatly reduce the amount of entanglement resources and need less classical bits. If we employ a maximally entangled cluster state as quantum channel, the probabilistic teleportation scheme becomes usual teleportation, the successful probability being 100%.展开更多
A protocol for quantum private comparison of equality(QPCE) is proposed based on five-particle cluster state with the help of a semi-honest third party(TP). In our protocol, TP is allowed to misbehave on its own but c...A protocol for quantum private comparison of equality(QPCE) is proposed based on five-particle cluster state with the help of a semi-honest third party(TP). In our protocol, TP is allowed to misbehave on its own but can not conspire with either of two parties. Compared with most two-user QPCE protocols, our protocol not only can compare two groups of private information(each group has two users) in one execution, but also compare just two private information. Compared with the multi-user QPCE protocol proposed, our protocol is safer with more reasonable assumptions of TP. The qubit efficiency is computed and analyzed. Our protocol can also be generalized to the case of 2N participants with one TP. The 2N-participant protocol can compare two groups(each group has N private information)in one execution or just N private information.展开更多
基金Project supported by the Fundamental Research Funds for the Central Universities,China(Grant No.531107040857)the Natural Science Foundation of Hunan Province,China(Grant No.851204035)the National Natural Science Foundation of China(Grant No.11774420)
文摘Using the tensor renormalization group method based on the higher-order singular value decomposition, we have studied the phase transitions of the five-state clock model on the square lattice. The temperature dependence of the specific heat indicates the system has two phase transitions, as verified clearly by the correlation function at three representative tem- peratures. By calculating the magnetic susceptibility, we obtained only the upper critical temperature as To2 = 0.9565（7）. Investigating the fixed-point tensor, we precisely locate the transition temperatures at Tcl = 0.9029（1） and Tc2 = 0.9520（1）, consistent well with the Monte Carlo and the density matrix renormalization group results.
基金Supported by the National Natural Science Foundation of China under Grant No. 10902083Shaanxi Natural Science Foundation under Grant No. 2009JM1007
文摘A scheme for controlled quantum state swapping is presented using maximally entangled five-qubit state,i.e.,Alice wants to transmit an entangled state of particle a to Bob and at the same time Bob wants to transmit an entangled state of particle b to Alice via the control of the supervisor Charlie.The operations used in this swapping process including C-not operation and a series of single-qubit measurements performed by Alice,Bob,and Charlie.
基金Supported by the National Natural Science Foundation of China under Grant Nos. 11147134, 11273008, and 51271059 and the Natural Science Foundation of Anhui Province University under Grant Nos. 2013A205 and 2012Z309
文摘A scheme for probabilistic teleportation of an unknown three-atom entangled state via a five-atom non- maximally entangled cluster state as quantum channel is proposed. In this scheme, the sender performs two Bell state and a single-atom measurements on the atoms, the receiver can reconstruct the original state with a certain probability by introducing an auxiliary atom and operating appropriate unitary transformations and controlled-not （C-not） operations according to the sender Alice＇s measurement results. As a result, the probability of successful teleportation is determined by the smallest two of the coefficients＇ absolute values of the cluster state. The considerable advantage of our scheme is that we employ a non-maximally entangled cluster state as quantum channel in the scheme, which can greatly reduce the amount of entanglement resources and need less classical bits. If we employ a maximally entangled cluster state as quantum channel, the probabilistic teleportation scheme becomes usual teleportation, the successful probability being 100%.
基金Supported by NSFC under Grant Nos.61402058,61572086the Fund for Middle and Young Academic Leaders of CUIT under Grant No.J201511+2 种基金the Science and Technology Support Project of Sichuan Province of China under Grant No.2013GZX0137the Fund for Young Persons Project of Sichuan Province of China under Grant No.12ZB017the Foundation of Cyberspace Security Key Laboratory of Sichuan Higher Education Institutions under Grant No.szjj2014-074
文摘A protocol for quantum private comparison of equality(QPCE) is proposed based on five-particle cluster state with the help of a semi-honest third party(TP). In our protocol, TP is allowed to misbehave on its own but can not conspire with either of two parties. Compared with most two-user QPCE protocols, our protocol not only can compare two groups of private information(each group has two users) in one execution, but also compare just two private information. Compared with the multi-user QPCE protocol proposed, our protocol is safer with more reasonable assumptions of TP. The qubit efficiency is computed and analyzed. Our protocol can also be generalized to the case of 2N participants with one TP. The 2N-participant protocol can compare two groups(each group has N private information)in one execution or just N private information.
