Nona Semana Integrada do Instituto de Física de São Carlos

Investigation of superfluid properties in quantum degenerate mixture of sodium and potassium: gray molasses implementation

Não agendado

20m

Palestrante

Sr. Edward Gutenberg Iraita Salcedo (Universidade de São Paulo - Instituto de Física de São Carlos )

Descrição

The objective of our global project is to produce a Bose-Einstein Condensate (BEC) of two bosonic species (Sodium 23 and Potassium 41-39) with the possibility to vary the interspecies interaction for the study of the superfluids aspects in different regimes. (1) Through the use of techniques as Stirring Beam and Feshbach Resonances will be possible the study the nucleation of vortices in a two species BEC with tunable interactions, exploring the different miscibility regimes between Na and K, as well as formation and studies in Quantum Turbulence. But to reach all that, we need to implement different techniques of cooling and increase the atomic density for both species. In this work we show the application of the technique known as the gray molasses (2-3), with the purpose of increasing the density in phase space of an atomic cloud of potassium 41. Various parameters were scanned as detuning's Raman as well as time of pulses and intensity of the beams. We report that from a MOT with 3.7E6 atoms to approximately 9 mK we get a temperature of approximately 25 uK. With this result, we have a cold sample sufficient to join with a second atomic species such as sodium in order to produce a mixture of atomic superfluids. Finally, we will implement the gray molasses technique in the sodium in order to have the two atoms with the same temperature, improving and optimizing the evaporative cooling processes.

Referências

1 PEÑAFIEL, E. E. P. Production of a Bose-Einstein condensate of sodium atoms and investigation
considering non-linear atom-photon interaction. 2016. 175 p. Thesis (Doctor in Science) - Instituto de Física de São Carlos, Universidade de São Paulo, São Carlos, 2016.
2 SHAHRIAR, M. S. et al. Continuous polarization-gradient precooling-assisted velocity-selective coherent population trapping. Physical Review A, v. 48, n. 6, p. R4035-R4038, Dec. 1993.
3 WEIDEMÜLLER, M. et al. A novel scheme for efficient cooling below the photon recoil limit. Europhysics Letters, v. 27, n. 2, p. 109-114, 1994.