qua·si·par·ti·cle /ˌkweˌzaɪˈpɑrtɪkəl, ˌsaɪ, ˌkwɑzi, si-/
  quasiparticle
  準粒子
  quasiparticle
       n : a quantum of energy (in a crystal lattice or other system)
           that has position and momentum and can in some respects
           be regarded as a particle