Thermodynamics, Statistical Physics, and Quantum Mechanics

THERMODYNAMICS AND STATISTICAL PHYSICS 185

e) Let us estimate the radius of a particle for which the radiation force will

equal the gravitational force at the distance of the Earth’s orbit Using

(S.4.73.6), we have

4.74 Hot Box and Particle Creation (Boston, MIT)

a) The number of photons is

where the factor 2 comes from the two polarizations of photons;

So,

b) At low temperatures we can disregard any interaction between photons

due to the creation of electron–positron pairs. We can therefore use the

standard formula for energy flux:

where is the Stefan–Boltzmann constant. On the other hand, by analogy
with molecular flow,

where the particle mass and