Cooling atomic ensembles with Maxwell's demon

Mark G. Raizen

Tsung-Yao Wu, Aishwarya Kumar, Felipe Giraldo +1 more

Stephen Travis Bannerman, Gabriel Price, Kirsten Viering +1 more

We demonstrate a general and efficient informational cooling technique for atoms that is an experimental realization of a one-dimensional Maxwell's demon. The technique transfers atoms from a magnetic trap into an optical trap via a single spontaneous Raman transition that is discriminatively driven near each atom's classical turning point. In this way, nearly all of the atomic ensemble's kinetic energy in one dimension is removed. We develop a simple analytical model to predict the efficiency of transfer between the traps and provide evidence that the performance is limited only by particle dynamics in the magnetic trap. Transfer efficiencies up to 2.2% are reported. We show that efficiency can be traded for phase-space compression, and we report compression up to a factor of 350. Our results represent a 15-fold improvement over our previous demonstration of the cooling technique.

D. Steck

T. Binnewies, Uwe Sterr, J. Helmcke +1 more

We present an alternative method for laser cooling of atoms close to the one-dimensional recoil limit. This method is particularly suited for atoms not accessible to conventional sub-Doppler cooling methods. It is based on the repeated selection and accumulation of slow atoms from a precooled atomic cloud and on the repeated rethermalization of the remaining atoms. The prepared ensemble is used to measure atom interferences with increased visibility.

Takanobu KISS

Light has proven to be a very useful means to influence the motion of atoms: to cool and to trap them. In molecules, however, there is usually a much richer variety of rotational and vibrational states. If they are thermally excited, the manipulation of an ensemble becomes difficult. We suggest that, in certain cases, non‐resonant interaction can achieve the addressing of single rovibrational levels. In our proposal a beam of diatomic molecules scattered off a standing wave laser mode splits according to the rovibrational quantum state of the molecules. We have found that single state resolution can be achieved by properly tuned, monochromatic light. The proposed scheme enables selecting non vibrating and non rotating molecules from a thermally excited beam. With this technique one could implement an instrument acting like Maxwell’s demon in order to prepare a rotationally and vibrationally cold molecular ensemble.