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1.
We present an efcient faithful multipartite polarization entanglement distribution protocol over an arbitrary noisy channel.The spatial degree of freedom is used to carry the entanglement during the transmission.We describe the principle by distributing n-qubit Greenberge–Horne–Zeilinger state and n-qubit W state.Our scheme can be used to distribute arbitrary n-qubit entangled states to n distant locations.The remote parties can obtain maximally entangled states deterministically on the polarization of photons.Only passive linear optics are employed in our setup,which makes our scheme more feasible and efcient for practical application in long distance quantum communication. 相似文献
2.
We introduce an attack scheme for eavesdropping freely the ping-pong
quantum communication protocol proposed by Bostr\"{o} m and Felbinger
[Phys. Rev. Lett. 89, 187902 (2002)] in a noise channel.
The vicious eavesdropper, Eve, intercepts and measures the travel
photon transmitted between the sender and the receiver. Then she
replaces the quantum signal with a multi-photon signal in the same
state, and measures the returned photons with the measuring basis,
with which Eve prepares the fake signal except for one photon. This
attack increases neither the quantum channel losses nor the error
rate in the sampling instances for eavesdropping check. It works for
eavesdropping the secret message transmitted with the ping-pong
protocol. Finally, we propose a way for improving the security of
the ping-pong protocol. 相似文献
3.
We propose an efficient hyperconcentration protocol for distilling maximally hyperentangled state from partially entangled pure state, resorting to the projection measurement on an auxiliary photon. In our scheme, two photons simultaneously entangled in polarization states and spatial modes are considered. One party performs quantum nondemolition detections on his photon and an additional photon to produce three photon hyperentangled state, then he projects the assistant photon into an orthogonal basis composed of both the polarization and spatial degree of freedom. Then the state of the left two photons collapses into maximally hyperentangled state with a certain probability. In the rest cases, some less-entangled states are obtained, which can be used as resource for the next round concentration. By repeating the concentration process for several rounds, a higher success probability can be obtained, which makes our scheme useful in practical quantum information applications. 相似文献
4.
An efficient quantum secure direct communication network protocol with the two-step scheme is proposed by using the Einstein-Podolsky-Rosen (EPR) pair block as the quantum information carrier. The server, say Alice, prepares and measures the EPR pairs in the quantum communication and the users perform the four local unitary operations to encode their message. Anyone of the legitimate users can communicate another one on the network securely. Since almost all of the instances in this scheme are useful and each EPR pair can carry two bits of information, the efficiency for qubits and the source capacity both approach the maximal values. 相似文献
5.
Controlled Teleportation of an Arbitrary Multi-Qudit State in a General Form with d-Dimensional Greenberger-Horne-Zeilinger States 总被引:3,自引:0,他引:3 下载免费PDF全文
A general scheme for controlled teleportation of an arbitrary multi-qudit state with d-dimensional Greenberger- Horne--Zeilinger (GHZ) states is proposed. For an arbitrary m-qudit state, the sender Alice performs m generalized Bell-state projective measurements on her 2m qudits and the controllers need only take some single-particle measurements. The receiver Charlie can reconstruct the unknown m-qudit state by performing some single-qudit unitary operations on her particles if she cooperates with all the controllers. As the quantum channel is a sequence of maximally entangled GHZ states, the intrinsic efticiency for qudits in this scheme approaches 100% in principle. 相似文献
6.
量子安全直接通信研究进展 总被引:1,自引:0,他引:1
简要地介绍了量子安全直接通信的必要条件,初步介绍了两个量子安全直接通信模型,即Two-Step和Quantum-One-Time-Pad模型。 The requirements of quantum secure direct communication (QSDC) are briefly introduced. Two QSDC schemes i. e. , the Two-Step QSDC scheme and the Quantum-One-Time-Pad QSDC scheme, are discussed in brief. 相似文献
7.
The first excited state and the ground state of ^17F are studied with the asymptotic normalization coefficient method. The results show that the probabilities of the last proton being out of the binding-potential in both the states are P = 59.71% and P = 27.61%, respectively. This means that the last nucleon in both the states of ^17F is far-extended beyond the range of nuclear force, especially in the first excited state. This result is also verified by the calculation of the density distributions of the last proton in ^17F. It is quantitatively confirmed that the first excited state of^1TF is a nuclear halo state and its ground state is a proton skin state. 相似文献
8.
Economical quantum secure direct communication network with single photons 总被引:1,自引:0,他引:1 下载免费PDF全文
In this paper a scheme for quantum secure direct communication
(QSDC) network is proposed with a sequence of polarized single
photons. The single photons are prepared originally in the same
state $\vert 0\rangle$ by the servers on the network, which will
reduce the difficulty for the legitimate users to check
eavesdropping largely. The users code the information on the single
photons with two unitary operations which do not change their
measuring bases. Some decoy photons, which are produced by operating
the sample photons with a Hadamard, are used for preventing a
potentially dishonest server from eavesdropping the quantum lines
freely. This scheme is an economical one as it is the easiest way
for QSDC network communication securely. 相似文献
9.
The exotic structures of the ground state of the mirror nuclei ^17Ne and ^17N are investigated by means of the asymptotic normalization coefficient (ANC) method to explore the role of the Coulomb interaction, The probebilities of a valence nucleon outside the binding-potential are P = 56.69±2.98/7.46% for ^17Ne and P = 45.51±2.32/5.81% for ^17N. The rms radii are (r^2)^1/2 = 5.06±0.11/0.30 fm and (r^2)^1/2=4.24±0.06/0.16 fm, respectively. The results obtained are nearly independent of the potential parameters. According to the halo occurrence conditions, it is suggested that ^17Ne is a two-proton halo and ^17N is a two-neutron skin. Moreover, two effects of the Coulomb interact-ion on the exotic structure are analysed. From the present results, the exotic structure of the nucleus in the proton-rich side is more obvious than that of its mirror nucleus because of the Coulomb interaction. 相似文献
10.
Probabilistic teleportation of an arbitrary GHZ-class state with a pure entangled two-particle quantum channel and its application in quantum state sharing 总被引:1,自引:0,他引:1 下载免费PDF全文
This paper presents a scheme for probabilistic teleportation of an
arbitrary GHZ-class state with a pure entangled two-particle quantum
channel. The sender Alice first teleports the coefficients of the
unknown state to the receiver Bob, and then Bob reconstructs the
state with an auxiliary particle and some unitary operations if the
teleportation succeeds. This scheme has the advantage of
transmitting much less particles for teleporting an arbitrary
GHZ-class state than
others. Moreover, it discusses the application of this
scheme in quantum state sharing. 相似文献