Bogoliubov vacuum
= Bogoliubov vacuum
{c}
{title2=$b_k|\Omega\rangle=0$}
A Bogoliubov vacuum is annihilated by the <quasiparticle> <linear operators> that diagonalize a stable <quadratic bosonic Hamiltonian>. If $a_k=u_kb_k-v_kb_{-k}^\dagger$, its original-mode <occupation number> is $|v_k|^2$. It is generally a <multimode squeezed vacuum> rather than the original <Fock vacuum>. In infinitely many modes, existence in the original <Fock space> requires a separate convergence analysis.