TY - JOUR
T1 - Optimal fidelity witnesses for gravitational entanglement
AU - Guff, Thomas
AU - Boulle, Nicolas
AU - Pikovski, Igor
N1 - Publisher Copyright:
© 2022 authors. Published by the American Physical Society. Published by the American Physical Society under the terms of the "https://creativecommons.org/licenses/by/4.0/"Creative Commons Attribution 4.0 International license. Further distribution of this work must maintain attribution to the author(s) and the published article's title, journal citation, and DOI. Funded by "https://www.kb.se/samverkan-och-utveckling/oppen-tillgang-och-bibsamkonsortiet/bibsamkonsortiet.html"Bibsam.
PY - 2022/2
Y1 - 2022/2
N2 - Optomechanical systems open new possibilities in fundamental research at the interface between quantum information and gravity. Recently, an ambitious experimental proposal was suggested by Bose et al. [S. Bose, A. Mazumdar, G. W. Morley, H. Ulbricht, M. Toroš, M. Paternostro, A. A. Geraci, P. F. Barker, M. S. Kim, and G. Milburn, Phys. Rev. Lett. 119, 240401 (2017)10.1103/PhysRevLett.119.240401] to measure the entanglement between two optomechanical systems generated by their gravitational interaction. The scheme relied on witnessing entanglement between the two systems. Here we develop a general framework to study the quality of bipartite entanglement witnesses using fidelity witnesses. We then apply this framework to the gravitational entanglement proposal, optimizing for the detection of entanglement. We construct a witness consisting of only five nontrivial spin measurements, which we compare with other proposed witnesses. With postprocessing our witness can detect entanglement for any choice of phases in the setup, up to a set of measure zero, for a closed system. We also explore the effects of a simple dephasing channel on this witness.
AB - Optomechanical systems open new possibilities in fundamental research at the interface between quantum information and gravity. Recently, an ambitious experimental proposal was suggested by Bose et al. [S. Bose, A. Mazumdar, G. W. Morley, H. Ulbricht, M. Toroš, M. Paternostro, A. A. Geraci, P. F. Barker, M. S. Kim, and G. Milburn, Phys. Rev. Lett. 119, 240401 (2017)10.1103/PhysRevLett.119.240401] to measure the entanglement between two optomechanical systems generated by their gravitational interaction. The scheme relied on witnessing entanglement between the two systems. Here we develop a general framework to study the quality of bipartite entanglement witnesses using fidelity witnesses. We then apply this framework to the gravitational entanglement proposal, optimizing for the detection of entanglement. We construct a witness consisting of only five nontrivial spin measurements, which we compare with other proposed witnesses. With postprocessing our witness can detect entanglement for any choice of phases in the setup, up to a set of measure zero, for a closed system. We also explore the effects of a simple dephasing channel on this witness.
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U2 - 10.1103/PhysRevA.105.022444
DO - 10.1103/PhysRevA.105.022444
M3 - Article
AN - SCOPUS:85125841411
SN - 2469-9926
VL - 105
JO - Physical Review A
JF - Physical Review A
IS - 2
M1 - 022444
ER -