Abstract
An anisotropic pseudopotential arising in the context of collisions of two particles polarized by an external field is rigorously derived and its properties are investigated. Such a low-energy pseudopotential may be useful in describing collective properties of dilute quantum gases, such as molecules polarized by an electric field or metastable atoms polarized by a magnetic field. The pseudopotential is expressed in terms of the reactance (K) matrix and derivatives of the Dirac function. In most applications, it may be represented as a sum of a traditional spherically symmetric contact term and an anisotropic part. The former contribution may be parametrized by a generalized scattering length. The anisotropic part of the pseudopotential may be characterized by the off-diagonal scattering length for dipolar interactions and off-diagonal scattering volume for quadrupolar interactions. The two-body matrix element of the pseudopotential in a basis of plane waves is also derived.
- Received 27 December 2002
DOI:https://doi.org/10.1103/PhysRevA.67.033607
©2003 American Physical Society