信道噪声对量子信息分离的影响 (Effect of Channel Noise on Quantum Information Splitting).

Dongfen Li

Ye Yeo, Timothy C. Ralph, Ping Koy Lam

10.1063/1.3630152

Yan-Qing Xie, YAN Kai, 黄雨梦 +1 more

We realize the quantum information splitting with respect to phase parameter through the quantum channel with multi-partite entangled states in the condition of the environmental noise. The protocol of quanutm information splitting is that the information encoded in quantum parameters from a sender can be recovered at any one of many receivers by means of measurements. It is found that a general partial measurement can help to enhance the quantum Fisher information under the influence of amplitude-damping noise. In the Markovian case, the values of quantum Fisher information are decreased monotically.In the non-Markovian case, there exists the oscillation of quantum Fisher information.

Kisong Lee, Jun‐Pyo Hong, Hyun-Ho Choi +1 more

A two-hop relay network is considered, in which an eavesdropper can overhear the relaying signal. To prevent the eavesdropper from decoding this signal, a destination transmits a jamming noise while a source transmits the data signal to the relay. At the same time, the relay can harvest energy from both the source signal and the jamming noise, and use this harvested energy to forward the received signal to the destination. In such a wireless-powered relay system with cooperative jamming, we propose two adaptive relaying schemes based on power splitting and time switching techniques. In the proposed power splitting-based relaying (PSR) and time switching-based relaying (TSR) schemes, the relay controls the power splitting ratio (p) and time switching ratio (α), respectively, in order to achieve a balance between signal processing and energy harvesting. We find analytically the optimal values of p and α in each scheme to maximize the secrecy capacity under the assumption of high signal-to-noise ratio (SNR). Interestingly, although the eavesdropper's channel state information (CSI) is used in the derivation of the optimal control parameters (p and α), they are shown not to be affected by the eavesdropper's CSI in a high SNR regime. This implies that the proposed schemes can be effective even for practical environments where there is no eavesdropper's CSI. Furthermore, simulation results show that they well coincide with the exact solutions in practical environments even though the closed-form solutions are obtained with a high SNR assumption. Moreover, the comparisons of PSR and TSR in various scenarios show that the two relaying schemes have complementary performances depending on the network conditions. Specifically, PSR achieves greater secrecy capacity than TSR when the channel condition is unfavorable to the eavesdropper for wiretapping.

Garry Bowen, Stefano Mancini

J. P. Gordon