Wave Atoms

Nuffield Advanced Physics team, Jon Ogborn

Roland Abfalterer, Stefan Bernet, Claudia Keller +3 more

Atoms interacting with standing light waves are a model system for the propagation of waves in static and time varying periodic media. We present here experiments studying the coherent motion of atomic deBroglie waves in periodic potentials made from on and off resonant light. We observe anomalous transmission of atoms through resonant standing light waves and experimentally confirm that atoms fulfilling the Bragg condition form a standing matter wave pattern. We furthermore demonstrate how Bragg diffraction of atomic matter waves at a time-modulated thick standing light wave can be used to coherently shift the deBroglie frequency of the diffracted atoms. Our frequency shifter for atomic matter waves is similar to an acousto-optic frequency shifter for photons.

Gao-Jian Zeng, Shi-Lun Zhou, Ao Sheng-Mei +1 more

In this paper, we study the behavior of a two-level atom in an electromagnetic wave of circular polarization. A general solution to the Schr\"odinger equation is obtained, and the action of the electromagnetic wave on the atom is analyzed in detail. It is shown that the levels of the atom would be split, with the energy difference between the split levels the same for the two states of the atom. The atom would acquire an average momentum, with its direction the same as the propagating direction of the electromagnetic wave, showing the expelling action of the electromagnetic wave on the atom; or with its direction opposite to the propagating direction of the electromagnetic wave, showing the trapping action of the electromagnetic wave on the atom. The properties of the action are dependent on the initial state of the atom. The average expelling and trapping forces exerted on the atom by the electromagnetic wave are determined. Two cases of ``resonance'' and ``strict detuning'' are discussed particularly. Under the resonance case, the transition probability reaches its maximum for a given time. In the strict detuning case, the atom is not influenced by the electromagnetic wave.

Maarten DeKieviet, Jörg Schmiedmayer

Cem Yuksel

Xiong Zhi

Based on this solution for Schrǒdinger equation, the atom lifetime in an electromagnetic wave of circular polarization is studied. When the frequency of a circularly polarized electromagnetic wave is equal to the atomic frequency, the atom lifetime of tow level atom is not influenced by the electromagnetic wave. For a ∧ type three level atom in a circularly polarized electromagnetic wave, we modulate the frequency of the electromagnetic wave to study the atom lifetime and show that the approximate condition in this paper is rational.