Casimir force induced by an imperfect Bose gas.
We present a study of the Casimir effect in an imperfect (mean-field) Bose gas contained between two infinite parallel plane walls. The derivation of the Casimir force follows from the calculation of the excess grand-canonical free energy density under periodic, Dirichlet, and Neumann boundary conditions with the use of the steepest descent method. In the one-phase region, the force decays exponentially fast when distance D between the walls tends to infinity. When the Bose-Einstein condensation point is approached, the decay length in the exponential law diverges with critical exponent ν(IMP) = 1, which differs from the perfect gas case where ν(P) = 1/2. In the two-phase region, the Casimir force is long range and decays following the power law D(-3), with the same amplitude as in the perfect gas.
Faculty of Physics, Institute of Theoretical Physics, University of Warsaw, Hoża 69, PL-00-681 Warsaw, Poland. Marek.Napiorkowski@fuw.edu.pl
Marek
M
Napiórkowski
Jarosław
J
Piasecki