can we say what is the pressure of single particle? answer is no.. in a similar way a single particle having temperature makes no sense... because temperature defined based on statistical data...
In statistical mechanics, one can describe the thermodynamics of a single particle within the canonical constant volume (or constant pressure) ensemble. This assumes that the particle can exchange energy with a suitable reservoir at thermal equilibrium.
my dear Kåre Olaussen , you are right ...but the same mechanism also concluded that temperature and entropy lose all meaning on the level of individual particles. and quantum mechanics still unlocked the secret of single particle, how equilibrium thermodynamics emerges . lets wait to unlock this secret..