Quantum Optics: Cat State Wigner Function

A Schrödinger cat state |ψ⟩ = N(|α⟩ + e^{iφ}|−α⟩) is a superposition of coherent states. Its Wigner quasiprobability distribution W(q,p) exhibits quantum interference fringes — a signature of non-classical correlations absent in classical phase space.

State

Amplitude |α|: 2.0 Phase φ (×π): 0.00 Fock n: 3 Resolution: 60

Wigner function: W(q,p) = (1/π) ∫ ψ*(q+y)ψ(q−y)e^{2ipy} dy
Negative values (blue) = non-classical. Fringes between coherent blobs = quantum interference.