Information, Quantum Computing, Physics.
mixing ratio 0<t<1 which maximizes the entropy S(ρ(t)). I expect that when ρ1=ρ2 and are pure states (of rank 1) then t can be any value 0<=t<=1 for maximum S, which I believe corresponds to the case where the second order derivative d2S(ρ(t))/dt2 = 0, the only exception to the concavity. This