Average fidelity estimation of twirled noisy quantum channel using unitary 2 t -design

2019 ◽  
Vol 28 (1) ◽  
pp. 010304
Author(s):  
Linxi Zhang ◽  
Changhua Zhu ◽  
Changxing Pei
Keyword(s):  
Quantum Channel ◽  
Average Fidelity ◽  
Noisy Quantum Channel

Photonic schemes of distribution and reconstruction of an entangled state from hybrid entanglement between polarization and time-bin via quantum dot

2022 ◽  
Author(s):  
Jino Heo ◽  
Seong Gon Choi
Keyword(s):  
Quantum Dot ◽  
Quantum Channel ◽  
Nonlinear Optical ◽  
Optical Devices ◽  
Entangled State ◽  
Experimental Conditions ◽  
Reliable Performance ◽  
Cavity System ◽  
Linear Optical ◽  
Noisy Quantum Channel

Abstract We propose photonic schemes for the distribution and reconstruction of a two-qubit entangled state using a hybrid entangled state under a noisy quantum channel. First, to generate a hybrid entangled state correlated with polarizations and time-bins, we employ a quantum dot (QD)-cavity system (nonlinear optical gate) and linear optical devices to implement controlled operation. These schemes can achieve the distribution and reconstruction of a two-qubit entangled state from hybrid entanglement by utilizing only linear optical devices without a QD-cavity system (i.e., a nonlinear optical device) for users who want to share an entangled state under a noisy quantum channel. For a feasible realization of the proposed schemes, we analyze the interaction between the photons and QD-cavity system and demonstrate the experimental conditions under which the reliable performance of the QD-cavity system is achieved.

Robust variations of secret sharing through noisy quantum channel

2014 ◽  
Vol 14 (7&8) ◽  
pp. 589-607
Author(s):  
Xiu-Bo Chen ◽  
Gang Xu ◽  
Yuan Su ◽  
Yi-Xian Yang
Keyword(s):  
Secret Sharing ◽  
Quantum Channel ◽  
Security Analysis ◽  
Information Leakage ◽  
Quantum Secret Sharing ◽  
The Other ◽  
Information Theoretic ◽  
Information Theoretic Security ◽  
Fundamental Requirement ◽  
Noisy Quantum Channel

In this paper, the perfect secret sharing in quantum cryptography is investigated. On one hand, the security of a recent protocol [Adhikari et al. Quantum Inform. \& Comput. 12 (2012) 0253-0261] is re-examined. We find that it violates the requirement of information theoretic security in the secret sharing and suffers from the information leakage. The cryptanalysis including several specific attack strategies are given, which shows that a dishonest participant can steal half or all of the secrets without being detected. On the other hand, we design a new quantum secret sharing protocol. The security of protocol is rigorously proved. It meets the fundamental requirement of information theoretic security. Furthermore, the security analysis including both the outside attacks and participant attacks is given in details. It is shown that our proposed protocol can achieve perfect secret sharing.

scholarly journals Capacity of the noisy quantum channel

1997 ◽  
Vol 55 (3) ◽  
pp. 1613-1622 ◽  
Author(s):  
Seth Lloyd
Keyword(s):  
Quantum Channel ◽  
Noisy Quantum Channel

ENTANGLEMENT SWAPPING OF PAIR CAT STATES

2011 ◽  
Vol 09 (03) ◽  
pp. 993-1003
Author(s):  
YE-QI ZHANG ◽  
JING-BO XU
Keyword(s):  
Quantum Channel ◽  
Quantum Teleportation ◽  
Continuous Variable ◽  
Entanglement Swapping ◽  
Final States ◽  
Average Fidelity ◽  
Logarithmic Negativity ◽  
Squeezed Vacuum ◽  
Schrödinger Cat ◽  
Cat States

We investigate the entanglement swapping of the continuous variable states by taking the pair Schrödinger cat states as the input entangled states, in which the two-mode squeezed vacuum and the pair cat states serve as the quantum channel, respectively. The entanglement of the initial states as well as the final states is analyzed by adopting the logarithmic negativity as the measure of entanglement. The quantum teleportation task by exploiting the swapped states as the quantum channel is also considered, where a coherent state serves as the target state and the average fidelity is examined.

scholarly journals QUANTUM ZERO-ERROR CAPACITY

2005 ◽  
Vol 03 (01) ◽  
pp. 135-139 ◽  
Author(s):  
REX A. C. MEDEIROS ◽  
FRANCISCO M. DE ASSIS
Keyword(s):  
Channel Capacity ◽  
Quantum Channel ◽  
Noisy Quantum Channel

We define a new kind of quantum channel capacity by extending the concept of zero-error capacity for a noisy quantum channel. The necessary requirement for which a quantum channel has zero-error capacity greater than zero is given. Finally, we point out some directions on how to calculate the zero-error capacity of such channels.

Improvement of a controlled quantum secure direct communication protocol

2014 ◽  
Vol 28 (15) ◽  
pp. 1450121 ◽  
Author(s):  
Dongsu Shen ◽  
Wenping Ma ◽  
Meiling Wang ◽  
Xunru Yin
Keyword(s):  
Quantum Channel ◽  
Communication Protocol ◽  
Quantum Secure Direct Communication ◽  
The Other ◽  
Secret Message ◽  
Entangled State ◽  
Direct Communication ◽  
Noisy Quantum Channel

A security loophole exists in Gao et al.'s controlled quantum secure direct communication protocol. By employing the security loophole, the receiver can obtain the secret message sent by the sender without the permission of the controller in their protocol. In order to avoid this loophole, we present an improved protocol in this paper. In the improved protocol, entangled particles are prepared at random in two GHZ-like states, which ensure that the receiver is not able to recover the secret message without knowing the initially entangled state. Compared with the other improved version whose security depends on the perfect quantum channel, our improved protocol is secure in a noisy quantum channel. Therefore, our protocol is more practical.

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