Recently Wei-Bo Gao et al.[Phys.Rev.Lett.104 (2010) 020501]; reported on the creation of a 4-photon6-qubit cluster state.It is shown this states can be utilized for perfect teleportation of arbitrary three qubit syste...Recently Wei-Bo Gao et al.[Phys.Rev.Lett.104 (2010) 020501]; reported on the creation of a 4-photon6-qubit cluster state.It is shown this states can be utilized for perfect teleportation of arbitrary three qubit systemsand controlled teleportation of an arbitrary two-qubit state.Therefore, the six-qubit cluster state as quantum channelsis equivalent to that of maximally six-qubit entangled state.展开更多
By using six-qubit decoherence-free （DF） states as quantum carriers and decoy states, a robust quantum secure direct communication and authentication （QSDCA） protocol against decoherence noise is proposed. Four si...By using six-qubit decoherence-free （DF） states as quantum carriers and decoy states, a robust quantum secure direct communication and authentication （QSDCA） protocol against decoherence noise is proposed. Four six-qubit DF states are used in the process of secret transmission, however only the ｜0＇〉 state is prepared. The other three six-qubit DF states can be obtained by permuting the outputs of the setup for ｜0＇〉. By using the ｜0＇〉 state as the decoy state, the detection rate and the qubit error rate reach 81.3%, and they will not change with the noise level. The stability and security are much higher than those of the ping-pong protocol both in an ideal scenario and a decoherence noise scenario. Even if the eavesdropper measures several qubits, exploiting the coherent relationship between these qubits, she can gain one bit of secret information with probability 0.042.展开更多
The perfect teleportation of an arbitrary three-qubit state with the highly entangled six-qubit genuine state introduced by Borras et al.(J.Phys.A: Math.Theor.40 (2007) 13407) is studied.Some appropriate measuring bas...The perfect teleportation of an arbitrary three-qubit state with the highly entangled six-qubit genuine state introduced by Borras et al.(J.Phys.A: Math.Theor.40 (2007) 13407) is studied.Some appropriate measuring bases the sender can take and the corresponding unitary operations the receiver should execute in terms of the sender’s measurement outcome are explicitly given.The flexibility between the measurement difficulty and the reconstruction difficulty is shown.Moreover,discussions and comparisons between our scheme and the recent incomplete scheme (Choudhury et al,J.Phys.A: Math.Theor.42 (2009) 115303) are made.展开更多
Using the highly entangled six-qubit genuine state we present a quantum private comparison(QPC)protocol, which enables two users to compare the equality of two bits of their secrets in every round comparison with the ...Using the highly entangled six-qubit genuine state we present a quantum private comparison(QPC)protocol, which enables two users to compare the equality of two bits of their secrets in every round comparison with the assistance of a semi-honest third party(TP). The proposed protocol needs neither unitary operations nor quantum entanglement swapping technology, both of which may consume expensive quantum devices. Single particle measurements and Bell-basis measurements, which are easy to implement with current technologies, are employed by two users and TP in the proposed protocol, respectively. The proposed protocol can withstand all kinds of outside attacks and participant attacks. Moreover, none of information about the two users' private secrets and the comparison result is leaked out to TP.展开更多
This study proposes the first high-capacity quantum secure direct communication(QSDC) with two-photon six-qubit hyperentangled Bell states in two longitudinal momentum and polarization degrees of freedom(DOFs) of phot...This study proposes the first high-capacity quantum secure direct communication(QSDC) with two-photon six-qubit hyperentangled Bell states in two longitudinal momentum and polarization degrees of freedom(DOFs) of photon pairs, which can be generated using two 0.5 mm-thick type-I β barium borate crystal slabs aligned one behind the other and an eight-hole screen. The secret message can be independently encoded on the photon pairs with 64 unitary operations in all three DOFs. This protocol has a higher capacity than previous QSDC protocols because each photon pair can carry 6 bits of information, not just 2 or 4 bits.Our QSDC protocol decreases the influence of decoherence from environment noise by exploiting the decoy photons to check the security of the transmission of the first photon sequence. Compared with two-way QSDC protocols, our QSDC protocol is immune to an attack by an eavesdropper using Trojan horse attack strategies because it is a one-way quantum communication.The QSDC protocol has good applications in the future quantum communication because of all these features.展开更多
Gilad Gour and Nolan R Wallach [J. Math. Phys. 51 112201(2010)] have proposed the 4-tangle and the square of the I concurrence. They also gave the relationship between the 4-tangle and the square of the I concurrence....Gilad Gour and Nolan R Wallach [J. Math. Phys. 51 112201(2010)] have proposed the 4-tangle and the square of the I concurrence. They also gave the relationship between the 4-tangle and the square of the I concurrence. In this paper, we give the expression of the square of the I concurrence and the n-tangle for six-qubit and eight-qubit by some local unitary transformation invariant. We prove that in six-qubit and eight-qubit states there exist strict monogamy laws for quantum correlations. We elucidate the relations between the square of the I concurrence and the n-tangle for six-qubit and eight-qubits. Especially, using this conclusion, we can show that 4-uniform states do not exist for eight-qubit states.展开更多
Recently, a genuine six-qubit entangled state Isix） has been proposed [Chen P X, et al. Phys Rev A, 2006, 74： 032324]. This state does not belong to the well-known three types of multipartite entangled states, i.e.,...Recently, a genuine six-qubit entangled state Isix） has been proposed [Chen P X, et al. Phys Rev A, 2006, 74： 032324]. This state does not belong to the well-known three types of multipartite entangled states, i.e., Greenberger-Home-Zeilinger （GHZ） state, W state, and linear cluster state. This state has many potential applications in quantum information processing. We pro- pose a scheme for generating such a genuine six-qubit entangled state for trapped ions in thermal motion. The scheme is insen- sitive to both the initial motional state and heating.展开更多
基金Supported by the National Natural Science Foundation of China under Grant No.10902083 Shaanxi Natural Science Foundation under Grant No.2009JM1007
文摘Recently Wei-Bo Gao et al.[Phys.Rev.Lett.104 (2010) 020501]; reported on the creation of a 4-photon6-qubit cluster state.It is shown this states can be utilized for perfect teleportation of arbitrary three qubit systemsand controlled teleportation of an arbitrary two-qubit state.Therefore, the six-qubit cluster state as quantum channelsis equivalent to that of maximally six-qubit entangled state.
基金supported by the National Natural Science Foundation of China(Grant No.61402058)the Science and Technology Support Project of Sichuan Province of China(Grant No.2013GZX0137)+1 种基金the Fund for Young Persons Project of Sichuan Province of China(Grant No.12ZB017)the Foundation of Cyberspace Security Key Laboratory of Sichuan Higher Education Institutions,China(Grant No.szjj2014-074)
文摘By using six-qubit decoherence-free （DF） states as quantum carriers and decoy states, a robust quantum secure direct communication and authentication （QSDCA） protocol against decoherence noise is proposed. Four six-qubit DF states are used in the process of secret transmission, however only the ｜0＇〉 state is prepared. The other three six-qubit DF states can be obtained by permuting the outputs of the setup for ｜0＇〉. By using the ｜0＇〉 state as the decoy state, the detection rate and the qubit error rate reach 81.3%, and they will not change with the noise level. The stability and security are much higher than those of the ping-pong protocol both in an ideal scenario and a decoherence noise scenario. Even if the eavesdropper measures several qubits, exploiting the coherent relationship between these qubits, she can gain one bit of secret information with probability 0.042.
基金partly supported by the program for New Century Excellent Talents at the University of China (Grant No.NCET-06-0554)the National Natural Science Foundation of China (Grant Nos.60677001,10747146 and 10874122)+3 种基金the Science-technology Fund of Anhui Province for Outstanding Youth (Grant No.06042087)the Key Fund of the Ministry of Education of China (Grant No.206063)the Talent Foundation of Higher Education of Anhui Province for Outstanding Youth (Grant No.2009SQRZ018)the Natural Science Foundation of Guangdong Province (Grant Nos.06300345 and 7007806)
文摘The perfect teleportation of an arbitrary three-qubit state with the highly entangled six-qubit genuine state introduced by Borras et al.(J.Phys.A: Math.Theor.40 (2007) 13407) is studied.Some appropriate measuring bases the sender can take and the corresponding unitary operations the receiver should execute in terms of the sender’s measurement outcome are explicitly given.The flexibility between the measurement difficulty and the reconstruction difficulty is shown.Moreover,discussions and comparisons between our scheme and the recent incomplete scheme (Choudhury et al,J.Phys.A: Math.Theor.42 (2009) 115303) are made.
基金Supported by National Natural Science Foundation of China under Grant No.61402407
文摘Using the highly entangled six-qubit genuine state we present a quantum private comparison(QPC)protocol, which enables two users to compare the equality of two bits of their secrets in every round comparison with the assistance of a semi-honest third party(TP). The proposed protocol needs neither unitary operations nor quantum entanglement swapping technology, both of which may consume expensive quantum devices. Single particle measurements and Bell-basis measurements, which are easy to implement with current technologies, are employed by two users and TP in the proposed protocol, respectively. The proposed protocol can withstand all kinds of outside attacks and participant attacks. Moreover, none of information about the two users' private secrets and the comparison result is leaked out to TP.
基金supported by the National Natural Science Foundation of China (Grant Nos. 11474027, 61675028, and 11674033)the Fundamental Research Funds for the Central Universities (Grant No. 2015KJJCA01)the National High Technology Research and Development Program of China(Grant No. 2013AA122902)
文摘This study proposes the first high-capacity quantum secure direct communication(QSDC) with two-photon six-qubit hyperentangled Bell states in two longitudinal momentum and polarization degrees of freedom(DOFs) of photon pairs, which can be generated using two 0.5 mm-thick type-I β barium borate crystal slabs aligned one behind the other and an eight-hole screen. The secret message can be independently encoded on the photon pairs with 64 unitary operations in all three DOFs. This protocol has a higher capacity than previous QSDC protocols because each photon pair can carry 6 bits of information, not just 2 or 4 bits.Our QSDC protocol decreases the influence of decoherence from environment noise by exploiting the decoy photons to check the security of the transmission of the first photon sequence. Compared with two-way QSDC protocols, our QSDC protocol is immune to an attack by an eavesdropper using Trojan horse attack strategies because it is a one-way quantum communication.The QSDC protocol has good applications in the future quantum communication because of all these features.
基金Supported by The National Natural Science Foundation of China(No.60807014)the Natural Science Foundation of Jiangxi Province,China(No.2009GZW0005)the Research Foundation of State Key Laboratory of Advanced Optical Communication Systems and Networks,and the Research Foundation of the Education Depart ment of Jiangxi Province,China(No.GJJ09153)
基金Supported by the Natural Science Foundation of Shaanxi Province(2004A15)by the Special Science Foundation of Education Bureau of Shaanxi Province(05JK288)
文摘Gilad Gour and Nolan R Wallach [J. Math. Phys. 51 112201(2010)] have proposed the 4-tangle and the square of the I concurrence. They also gave the relationship between the 4-tangle and the square of the I concurrence. In this paper, we give the expression of the square of the I concurrence and the n-tangle for six-qubit and eight-qubit by some local unitary transformation invariant. We prove that in six-qubit and eight-qubit states there exist strict monogamy laws for quantum correlations. We elucidate the relations between the square of the I concurrence and the n-tangle for six-qubit and eight-qubits. Especially, using this conclusion, we can show that 4-uniform states do not exist for eight-qubit states.
基金supported by the National Natural Science Foundation of China (Grant Nos. 61071025 and 61172047)the Important Program of Hunan Provincial Education Department (Grant No. 06A038)+1 种基金Department of Education of Hunan Province (Grant No. 06C080)Hunan Provincial Natural Science Foundation, China (Grant No. 07JJ3013)
文摘Recently, a genuine six-qubit entangled state Isix） has been proposed [Chen P X, et al. Phys Rev A, 2006, 74： 032324]. This state does not belong to the well-known three types of multipartite entangled states, i.e., Greenberger-Home-Zeilinger （GHZ） state, W state, and linear cluster state. This state has many potential applications in quantum information processing. We pro- pose a scheme for generating such a genuine six-qubit entangled state for trapped ions in thermal motion. The scheme is insen- sitive to both the initial motional state and heating.
