ZERO-POINT ENERGY OF A DILUTE DIELECTRIC BALL IN THE MODE SUMMATION METHOD

Abstract

In the (ε1-ε2)2-approximation the Casimir energy of a dilute dielectric ball is derived using a simple and clear method of the mode summation. The addition theorem for the Bessel functions enables one to present in a closed form the sum over the angular momentum before the integration over the imaginary frequencies. The linear in (ε1-ε2)2 contribution into the vacuum energy is removed by an appropriate subtraction. The role of the contact terms used in other approaches to this problem is elucidated.