RUI Collaboration: Designing Ultra-cold Atom Circuits in Quasi-2D Confinement

This theoretical research program, to be performed by a collaboration between Dr. Mark Edwards of Georgia Southern University and Dr. Charles W. Clark of the Joint Quantum Institute (JQI), an institute run jointly by the University of Maryland and the National Institute of Standards and Technology (NIST), will be devoted to the design and study of new 'atom circuits' for the purpose of developing an ultra-precise rotation sensor and for gaining a greater fundamental understanding of quantum matter at ultra-cold temperatures. An 'atom circuit' is an atomic gas confined by laser light and held at temperatures just a few billionths of a degree above absolute zero. Gases of identical atoms confined at such low temperatures cause the constituent atoms to exhibit their wave-like quantum nature and the gas can form a state called a 'Bose-Einstein condensate' (BEC). A BEC is a system of identical atoms all of whose matter-wave shapes are the same. Bose-Einstein-condensed gases can be manipulated by the confining laser light into arbitrary shapes such as rings and the atoms can be made to flow around circuits within the confinement. Such systems are called 'atom circuits'. These circuits have the potential to be at the heart of quantum devices that can sense rotations and magnetic and gravitational fields in an ultra-precise way. This research program will design new atom circuits and develop theoretical tools for characterizing and probing them. This work will performed in close collaboration with experimental researchers at JQI/NIST.

This research program is designed to enable two talented Georgia Southern University undergraduate physics majors to gain cutting-edge research experience in the area of ultra-cold atom theory thus advancing discovery while promoting learning. Edwards and the Georgia Southern students will communicate with both the JQI research group headed by Charles Clark and with members of the Laser Cooling and Trapping group at NIST, headed by Gretchen Campbell, using Google Hangout. Georgia Southern students will attend the weekly Quantum Information/Bose-Einstein meetings at NIST via the internet. The project will enhance the infrastructure for research and education by maintaining an established collaboration among an undergraduate institution (GA Southern), a national laboratory (NIST), and a major research university (University of Maryland). Broad dissemination to enhance scientific and technological understanding will be accomplished by bringing distinguished scientists to the Georgia Southern University campus to present colloquia and by developing visualization capabilities with the new digital projection system in the Georgia Southern Planetarium. Finally, new atom-circuits have the potential to be at the heart of a new generation of practical devices that will find applications in navigation, metrology, geodesy, and studies of the fundamental properties of matter.

This collaboration will conduct a theoretical exploration of various designs of atom circuits formed by confining a Bose-Einstein condensate (BEC) gas in an optical potential consisting of a horizontally oriented red-detuned light sheet and an arbitrary two-dimensional potential within this plane created by various red- and blue-detuned laser beams. Advances in optical trapping technology have enabled the creation of ultra-cold atom systems strongly confined in the vertical direction while being subject to an arbitrary potential in the horizontal plane. New atom-circuit potentials will be devised and studied. Studies of these systems will include (1) circuit behavior, (2) development of simple models of circuit operation analogous to Kirchhoff's rules for electronic circuits, (3) theoretical development of possible experimental probes to measure parameters appearing in these simple models, (4) effects of the environment, such as finite temperature, on circuit operation. The major tools that will be developed will be the Zaremba-Nikuni-Griffin (ZNG) theory in the laboratory and rotating frame. The ZNG theory treats the system as a combination of a BEC and a thermal cloud that can be weakly perturbed. The result is a finite-temperature, non-equilibrium system.