  We analyze the oscillations of Rydberg atoms in the framework of quantum
field theory and we reveal non-trivial vacuum energy which has the equation of
state of the dark matter. This energy is similar to that expected for mixed
neutrinos and affects the thermal capacity of the gas. Therefore, the
deflection of the thermal capacity of Rydberg atoms could prove the condensate
structure of vacuum for mixing fermions and open new scenarios in the study of
the dark components of the universe.
