Coherent state |alpha> = e^{-|alpha|^2/2} sum alpha^n/sqrt(n!) |n>; permutation/factorial

Coherent-state framework (Schroedinger 1926 Naturwissenschaften 14, 664; Glauber 1963 Phys Rev 130, 2529). Setup: the coherent state |alpha> of a single optical mode is the eigenstate of the annihilation operator a |alpha> = alpha |alpha>,…