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Adiabatic trap deformation for preparing quantum Hall states
Dr. Marco Roncaglia Politecnico di Torino, Italia
26.11.2010 at 10:15
Abstract:
One of the biggest challenges in physics of trapped ultracold atoms is the observation of thequantum Hall effect (QHE), when a gas of bosonic atoms is put in rapid rotation. A considerableexperimental effort have been spent in this direction, but some fundamental obstacles seem toprevent the gas from going beyond the vortex-lattice phase when rotation is generated bystirring the gas inside a harmonic trap.One of the main obstacles consists in the difficulty of imparting to the system a sufficientamount of angular momentum. Here, we discuss and propose feasible schemes for preparingadiabatically quantum-Hall states starting from a gas initially confined in a ring by using a“Mexican-hat” potential with a strong bump at the center. Setting a given rotation speed of thering, it is possible to inject into the atomic gas an appropriate quantity of angular momentum,stored in the form of a giant vortex state. Afterwards, the potential is adiabatically deformedinto a harmonic trap. We provide clear numerical evidence that the interacting bosonic gas inthe ring for some precise values of angular frequency is indeed adiabatically connected withknown quantum-Hall states, like the n=1/2 Laughlin or the n=1 Pfaffian.
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