Probing Planckian physics in de Sitter space with quantum correlations

Jun Feng, Cheng-Yi Sun, Wen-Li Yang, Yao-Zhong Zhang, Heng Fan

Published 2012-11-13, updated 2014-10-19Version 2

We study the quantum correlation and quantum communication channel of both free scalar and fermionic field in de Sitter space, while the Planckian modification presented by choice of a particular $\alpha$-vacuum has been considered. We show that the occurrence of degradation of quantum entanglement between field modes for an inertial observer in curved space, due to the radiation associated with his cosmological horizon. Comparing with standard Bunch-Davies choice, the possible Planckian physics causes some extra decrement on the quantum correlation, which may provide the means to detect quantum gravitational effects via quantum information methodology in future. Beyond single-mode approximation, we construct proper Unruh modes admitting general $\alpha-$vacua, and find a convergent feature of both bosonic and fermionic entanglement. In particular, we show that the convergent points of fermionic entanglement negativity are dependent on the choice of $\alpha$. Moreover, an one-to-one correspondence between convergent points $H_c$ of negativity and zeros of quantum capacity of quantum channels in de Sitter space has been proved.