Beating the Standard Quantum Limit for Nonorthogonal Multi-State Discrimination
F. E. Becerra, Jingyun Fan, G. Baumgartner, J. Goldhar, Jon T. Kosloski, Alan L. Migdall · 2013
We demonstrate a quantum receiver that discriminates four nonorthogonal states with error probabilities below the standard quantum limit (SQL) for a wide range of input powers and as much as 6 dB below the SQL.