Identifying quantumness via addition-then-subtraction operation
  We propose a measure of quantumness based on an addition-then-subtraction operation. We demonstrate how this measure can distinguish between classical and bosonic particles by investigating in detail multi-particle bosonic systems. Experimental schemes implementing this measure for bosons in all-optical and atom-cavity systems are provided. We also apply this measure to single-mode fermionic systems. 
Su-Yong Lee, Changsuk Noh, and Dagomir Kaszlikowski
quant-ph