On the Universality of the Einstein-Podolsky-Rosen Phenomenon

Jeno M. Barnothy

Peter Mittelstaedt

Zhongzhong Qin, Xiaowei Deng, Caixing Tian +4 more

Einstein-Podolsky-Rosen (EPR) steering exhibits an inherent asymmetric feature that differs from both entanglement and Bell nonlocality, which leads to one-way EPR steering. Although this one-way EPR steering phenomenon has been experimentally observed, the schemes to manipulate the direction of EPR steering have not been investigated thoroughly. In this paper, we propose and experimentally demonstrate three schemes to manipulate the direction of EPR steering, either by varying the noise on one party of a two-mode squeezed state (TMSS) or transmitting the TMSS in a noisy channel. The dependence of the direction of EPR steering on the noise and transmission efficiency in the quantum channel is analyzed. The experimental results show that the direction of EPR steering of the TMSS can be changed in the presented schemes. Our work is helpful in understanding the fundamental asymmetry of quantum nonlocality and has potential applications in future asymmetric quantum information processing.

J. S. Bell

Meihong Wang, Zhongzhong Qin, Xiaolong Su

Einstein-Podolsky-Rosen (EPR) steering is a quantum mechanical phenomenon that allows one party to steer the state of a distant party by exploiting their shared entanglement. It has potential applications in secure quantum communication. In this paper, we present two swapping schemes of Gaussian EPR steering, single-channel and dual-channel schemes, by the technique of entanglement swapping. Two space-separated independent EPR steering states without a direct interaction present EPR steering after deterministic swapping. By comparing the EPR steering of the single-channel and dual-channel schemes, we show that the transmission distance of the single-channel scheme is much longer than that of the symmetric dual-channel scheme. Different from entanglement swapping, one-way EPR steering is presented after swapping over lossy channels. The most interesting thing is that the change of the EPR steering direction is observed in the dual-channel scheme. We also show that excess noise in a quantum channel will shorten the transmission distance of the swapping, even leading to the sudden death of EPR steering. The presented schemes provide a technical reference for remote quantum communications with EPR steering.

Yi-Zheng Zhen, Yu-Lin Zheng, Wen-Fei Cao +4 more

Uncertainty principle lies at the heart of quantum mechanics, while nonlocality is an intriguing phenomenon of quantum mechanics to rule out local causal theories. One subtle form of nonlocality is so-called Einstein-Podolsky-Rosen (EPR) steering, which holds the potential for shared entanglement verification even if the one-sided measurement device is untrusted. However, certifying EPR steering remains a big challenge presently. Here, we employ the local uncertainty relation to provide an experimental friendly approach for EPR steering verification. We show that the strength of EPR steering is quantitatively linked to the strength of the uncertainty relation, as well as the amount of entanglement. We find also that the realignment method works for detecting EPR steering of an arbitrary dimensional system.