QED Fluctuation-Induced Pressure
Equilibrium (zero or finite temperature)
"On
the attraction between two perfectly conducting plates,"
H.B.G.
Casimir, Proc. K. Ned. Akad. Wet. 51,
793 (1948)
Quantum fluctuations
of electromagnetic field in the vacuum between leads to an attractive force between perfect mirrors
"The
Theory of Molecular Attractive Forces Between Solids,"
E.M.
Lifshitz, Soviet Physics 2,
73 (1956),
Generalizes the result by considering fluctuating current sources in the bodies, and to finite temperatures.
Non-equilibrium steady state (different temperatures)
Radiation Pressure at short separations pressure is non-classical and dominated by evanescent waves.
"Casimir-Lifshitz force out of thermal equilibrium,"
M. Antezza, L.P. Pitaevskii, S. Stringari, V.B. Svetovoy, Phys. Rev. A 77, 022901 (2008)
A generalized approach for computation of Casimir forces, as well as radiation and heat transfer.
"Nonequilibrium Electromagnetic Fluctuations: Heat Transfer and Interactions,"
M. Krüger, T. Emig, and M. Kardar, Phys. Rev. Lett. 106, 210404 (2011)
Rytov (1959): 
"Fluctuational QED"
Fluctuating currents in each object are related to its temperature by a fluctuation-dissipation condition:
The EM field due to thermal fluctuations of one object is related to overall Green's function by:
The overall fluctuations with many objects at different temperatures is then given by:
From EM correlations follow the stress tensor and the Poynting vector, hence forces and radiation.
