On upper bounds in the Fröhlich polaron model

Resumo

We show that a sequence of improving upper bounds to the ground state energy of the quantized Fröhlich polaron model can be obtained in a regular way by means of combining a variational method originated from the theory of coherent states with a generalized variational approach in quantum mechanics. Due to their variational nature, these bounds hold for arbitrary strength of the electron–phonon interaction.