Fault-tolerant high-capacity quantum key distribution over a collective-noise channel using extended unitary operations

2014 ◽  
Vol 13 (7) ◽  
pp. 1523-1535 ◽  
Author(s):  
Hong Lai ◽  
Mehmet A. Orgun ◽  
Jinghua Xiao ◽  
Liyin Xue
2009 ◽  
Vol 07 (08) ◽  
pp. 1479-1489 ◽  
Author(s):  
XI-HAN LI ◽  
BAO-KUI ZHAO ◽  
YU-BO SHENG ◽  
FU-GUO DENG ◽  
HONG-YU ZHOU

We present two robust quantum key distribution protocols against two kinds of collective noise, following some ideas in quantum dense coding. Three-qubit entangled states are used as quantum information carriers, two of which form the logical qubit, which is invariant with a special type of collective noise. The information is encoded on logical qubits with four unitary operations, which can be read out faithfully with Bell-state analysis on two physical qubits and a single-photon measurement on the other physical qubit, not three-photon joint measurements. Two bits of information are exchanged faithfully and securely by transmitting two physical qubits through a noisy channel. When the losses in the noisy channel is low, these protocols can be used to transmit a secret message directly in principle.


2005 ◽  
Vol 13 (23) ◽  
pp. 9415 ◽  
Author(s):  
Yun-kun Jiang ◽  
Xiang-Bin Wang ◽  
Bao-Sen Shi ◽  
Akihisa Tomita

2010 ◽  
Vol 08 (07) ◽  
pp. 1141-1151 ◽  
Author(s):  
XI-HAN LI ◽  
XIAO-JIAO DUAN ◽  
FU-GUO DENG ◽  
HONG-YU ZHOU

Quantum entanglement is an important element of quantum information processing. Sharing entangled quantum states between two remote parties is a precondition of most quantum communication schemes. We will show that the protocol proposed by Yamamoto et al. (Phys. Rev. Lett.95 (2005) 040503) for transmitting single quantum qubit against collective noise with linear optics is also suitable for distributing the components of entanglements with some modifications. An additional qubit is introduced to reduce the effect of collective noise, and the receiver can take advantage of the time discrimination and the measurement results of the assistant qubit to reconstruct a pure entanglement with the sender. Although the scheme succeeds probabilistically, the fidelity of the entangled state is almost unity in principle. The resource used in our protocol to get a pure entangled state is finite, which establishes entanglement more easily in practice than quantum entanglement purification. Also, we discuss its application in quantum key distribution over a collective channel in detail.


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