Spatial separation of mixed states of atoms and molecules in the field of a traveling radio wave

B. D. Agap'ev, M. B. Gornyi, Boris G. Matisov

Chong Ye, Libin Fu, Jie Liu

Abstract We propose a theoretical scheme to separate a molecular cloud from atoms in analogy to the spin Hall effect and to completely transfer Feshbach molecules to the ground state by applying a spatially modulated laser field to an atom–molecule mixed gas. In particular, the laser–molecule interaction induces a synthetic U (1) gauge potential for the dressed molecular dark state. Through numerical simulation, we demonstrate that such a gauge field leads to a spin Hall separation of atoms and molecules. In such a process, molecules can be transformed into the ground state completely.

Otto Robert Frisch

Summary Molecular beams are beams of molecules (which may be single atoms) travelling through vacuum at thermal velocities. They have been used to explore many properties of atoms and molecules, chiefly through their deflection in magnetic and electric inhomogeneous fields. Atomic beams first clearly established the phenomenon of space quantization, which means that the magnetic (or electric) energy of an atomic system in a given field can have only certain discrete values, and is not a continuum as classical physics supposed. Transitions between those energy states can be induced by radio-frequency fields; sharp resonances are observed and can be used to get accurate values of atomic and nuclear constants or to provide accurate frequency standards ('atomic clocks'). Molecular beams have also been used to test de Broglie's surmise that beams of particles should show wave properties (diffraction), to study collisions between molecules, and to supply spectroscopic sources in which the line broadening by Doppler effect is greatly reduced.

B. D. Agap'ev, M. B. Gornyi, Boris G. Matisov

R. G. Dall, L. J. Byron, Andrew G. Truscott +3 more

A method to create paired-atom laser beams from a metastable helium atom laser via four-wave mixing is demonstrated. Radio-frequency outcoupling is used to extract atoms from a Bose-Einstein condensate near the center of the condensate and initiate scattering between trapped and untrapped atoms. The unequal strengths of the interactions for different internal states allows an energy-momentum resonance which leads to the creation of pairs of atoms scattered from the zero-velocity condensate. The resulting scattered beams are well separated from the main atom laser in the two-dimensional transverse atom laser profile. Numerical simulations of the system are in good agreement with the observed atom laser spatial profiles and indicate that the scattered beams are generated by a four-wave mixing process, suggesting that the beams are correlated.

G. A. Delone, V. A. Grinchuk, A. P. Kazantsev +1 more