Bogoliubov quasiparticle
= Bogoliubov quasiparticle
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A Bogoliubov <quasiparticle> is an excitation created by the diagonal mode operator obtained through a <Bogoliubov transformation>. Its vacuum can contain particles in the original modes because creation and <annihilation operators> mix. Examples include <antiferromagnetic spin waves>, Bose-gas <phonons> and paired-fermion excitations.