Obtainment of thermal noise from a pure quantum state
Bernard Yurke, Mary J. Potasek · Physical Review A · 1987
It is shown that if one has access to only one mode of a two-mode squeezed-vacuum state, the photon statistics of this mode is indistinguishable from that of a thermal distribution. Parametric interactions that give rise to two-mode squeezing thus provide a mechanism for thermalization that is intrinsically quantum mechanical.