[Triumf-seminars] This week's colloquium speaker Ian Spielman

[TRIUMF Seminars]

Dear TRIUMF Seminars Subscriber,

This week's TRIUMF Colloquium, entitled "Observation of Zitterbewegung in a degenerate quantum gas," will be delivered by Ian Spielman of the University of Maryland and the National Institute of Standards and Technology on Thursday at 14:00 in the auditorium. His abstract is appended below. Dr. Spielman will be here on Thursday throughout the day. If you would like to meet with him individually or in a group, or have dinner with him on Thursday evening, please send an email to davids at triumf.ca with your preferred time(s).

Thanks,

Barry

Here I present our experimental work on Bose-Einstein condensates, systems of ultra-cold charge neutral atoms at a temperature of about 100 nano-Kelvin: one billion times colder than room temperature. These condensates – quantum gases – are nearly perfect quantum mechanical systems, and here we demonstrate a technique by which these charge neutral particles have artificial spin-orbit coupling, of a form more well known in material systems.

In one limit, this spin-orbit coupled system is described by the 1D relativistic Dirac equation. Among the earliest predictions of relativistic quantum mechanics is Schrodinger’s suggestion that a relativistic quantum particle, such as an electron, should undergo a microscopic trembling – Zitterbewegung – is it moves. For the electron, the f = mc^2/h= 1 × 10^20 Hz frequency and deltax = h/mc = 2 pm amplitude of this motion are below any foreseeable threshold for detection. This desperate situation can be happily resolved by working with artificial relativistic systems such as graphene, or as here with ultracold atoms where the effective speed of light c* can be vastly decreased and where the effective mass m* is tunable. In our experiment, where c* = 11.6 mm/s, f = 1 kHz and deltax = 0.5 µm, Zitterbewegung is easily observed.

In our engineered system, we observed Zitterbewegung and directly measured the frequency and amplitude of this microscopic motion, and find it to be in agreement with our relativistic model.
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