A First-Principles Method of Determining Van Der Waals Forces in a Dissipative Media

Lifshitz theory of van der Waals (vdW) force and energy is strictly valid when the location at which the stress tensor is calculated is in vacuum. Generalization of Lifshitz theory to the case when the stress tensor is to be calculated in a dissipative material, as opposed to vacuum, is a surprisingly difficult undertaking because there is no expression for the electromagnetic stress tensor in dissipative materials. Here, we derive the expression for vdW force in planar dissipative media by calculating the Maxwell stress tensor in a fictious layer of vacuum, that is eventually made to vanish, introduced in the structure, without employing the complicated quantum field theoretic method proposed by Dzyaloshinskii, Lifshitz, and Pitaevskii. Even though this work has proven to be a corroboration of Dzyaloshinskii et al., it has thrown new light on our understanding of vdW forces and suggests that it should be possible to achieve the similar result for objects with arbitrary shapes.