Investigating and controlling the quantum resources of bipartite-qubit detectors of scalar fields in the process of spacetime expansion

Abstract

Quantum resources construct new avenues to explore the cosmos. Considering bipartite-qubit detectors subjected to scalar fields in an expanding spacetime, quantum resources (including quantum coherence, quantum discord, Bell-nonlocality, and nonlocal advantage of quantum coherence) of the system are characterized. The influences of various cosmic parameters on these quantum resources are investigated. Besides, we use the filtering operation to propose a strategy that can be used to control these quantum resources. The results reveal that quantum coherence and quantum discord can not disappear at different expansion rapidity, expansion volumes, and particle masses of scalar field. Conversely, one can not capture Bell-nonlocality and nonlocal advantage of quantum coherence at higher expansion rapidity, larger expansion volume, and smaller particle mass. The dissipation of quantum resources can be resisted via the filtering operation. One can use the filtering operation to remarkably strengthen these quantum resources of the system.

Suppressing the degeneration of quantum resources through coupling auxiliary qubits

“…Recently, the QC has been used to reveal the nonclassical characteristics of various systems. Involving superinductors [36], two-level molecular system [37], polariton condensates [38], critical unstable two-level systems [39], quantum dot systems [40], cavity magnomechanical systems [41], quantum batteries [42], neutrino [43], linear systems of equations [44], dipolar interacting magnetic system [45], Heisenberg model [46], noninertial frame [47], and spacetime expansion [48]. Besides, reservoir system is significant for quantum information [49], and the transformation between coherence and entanglement of reservoir system was revealed by Hu et al [50].…”

“…The l 1 norm of coherence is most effective in witnessing the NAQC, and it can detect more NAQC states. After that, variously paramount efforts have been reported [53][54][55][56][57][58], including the hierarchy between the NAQC and Bell nonlocality [54], the NAQC of high-dimensional system [55], the NAQC under sequential observers [56], the experimental investigation concerning the NAQC [57], and the realizations of the NAQC in a variety of quantum systems [48,[59][60][61][62]. Recently, some novel conclusions have been revealed.…”