Fock approximation to the large polaron in a magnetic field

Abstract

We study the large polaron ground state energy in the presence of a constant and uniform magnetic field within the Fock approximation. By use of a new trial spectrum we find a new upper bound to the ground state energy for all magnetic fields and electron–phonon coupling constants. The trial spectrum has the novel feature of keeping cylindrical symmetry for certain values of coupling, even in the absence of magnetic field.