CAREER: Making a Difference in First Generation and Underrepresented Students' Education through Research: Quantum Coherence in a Bose Thermal Gas

Cold atomic gases are promising candidates for applications in quantum computing and precision sensors, owing to their wave-like, coherent nature exhibited at low temperatures. Fully-coherent samples, so-called “quantum gases”, are achieved when cooled to near absolute zero, but this is technically challenging. Recent work, though, has demonstrated that internal quantum coherence can persist even in thermal gases whose temperatures are well above those required to create a quantum gas.

The first goal of this project is to determine the limiting conditions for which quantum coherence is preserved in these thermal gases. As such, it will probe the boundary between the classical and quantum regimes and may aid in the development of low-cost quantum technologies. The second goal is to investigate such a gas as it transitions from a thermal cloud to a quantum gas.

Depending on the conditions of the experiment, the quantum properties can be either suppressed or enhanced, affecting the complexity of computations and the precision of measurements. The third goal of this project is to integrate quantum science research into undergraduate education. If successful, this will provide a model to make quantum science research more accessible to undergraduate-only institutions, providing enhanced learning opportunities to underrepresented groups in physics.

The experimental research program will measure ultracold atomic spinor gases with three main goals. The first goal of the project is to determine the maximum temperature for a Bose thermal gas to exhibit coherent spin-changing collisions. All-optical trapping of spinor gases will be utilized to probe the spinor dynamics of samples as a function of temperature.

A thermal gas will be coherently prepared with the desired initial spin state, and the resulting population oscillations will be measured through absorption imaging of the magnetic sublevels. Second, the project will investigate coherent spin-changing collisions in the temperature regime as a thermal gas transitions to a Bose-Einstein condensate. Although the limiting cases are well-understood, there is currently no theoretical model to describe this intermediate regime.

It has been argued that spin-locking between the thermal and Bose-condensed components, for example, can lead to either an enhancement or suppression of the coherence of the thermal cloud. The loss of coherence limits the complexity of computation in quantum information systems and the precision of measurements. Experimental studies will provide needed measurements to develop accurate theoretical models.

Third, the project will integrate education and research in quantum physics with reduced technical requirements suitable for primarily undergraduate institutions, providing enhanced learning opportunities for underrepresented groups.

This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.