Fundamental Limitation on the Detectability of Entanglement

Sep. 2021 - Aug.2022, THU
Pengyu Liu, Zhenhuan Liu, Shu Chen, Xiongfeng Ma
  • Prove that any entanglement criterion needs exponentially many observables to detect entanglement effectively. Otherwise, the detection capability of the criterion will decay double-exponentially.
  • Propose a systematic method for quantifying the detection capability of entanglement criteria.
  • Bound the detection capability of many common-used entanglement criteria, including entanglement witnesses, positive maps, and faithful entanglement criteria.
  • Show a quantum advantage in entanglement detection tasks using multi-copy measurements.