COLD RYDBERG ATOMS AS REALIZABLE ANALOGS OF CHERN-SIMONS THEORY

The angular momentum spectrum of an atomic dipole in constant electric and magnetic fields is calculated. The arrangement of the fields are such that the motion of the dipole is planar and rotationally symmetric, with the result that the Röntgen term of the Lagrangian takes on the appearance of a Chern-Simons interaction. On eliminating the kinetic energy term of the Lagrangian, the angular momentum spectrum changes from one consisting of integers to one consisting of positive half integers. The possibility of physically achieving such an elimination is discussed in the context of cold Rydberg atoms. © 1995 The American Physical Society.