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JQI Postdoctoral Seminars

December 1, 2014 - 11:00am
JQI Postdocs

Speaker: Edwin Barnes; University of Maryland

Title: Robust quantum control using smooth pulses and topological winding

Abstract: One of the primary challenges in controlling microscopic quantum systems is the decoherence induced by the environment. I will present a general approach to constructing smooth, intrinsically robust driving fields which automatically cancel the leading-order noise-induced errors in a qubit's evolution exactly.

Speaker: Zhexuan Gong; University of Maryland

Title: Topological phases with long-range interactions

Abstract: Whether topological phases survive in the presence of long-range interactions is an important yet largely unanswered question. We show that, surprisingly, the spin-1 Haldane chain remains in its topological phase in the presence of arbitrarily slow algebraic decay of the interactions. Our findings can be readily tested in an experimental trapped-ion quantum simulator.
Speaker: Elizabeth Goldschmidt; University of Maryland
Title: Quantum magnetization dynamics in an optical lattice
Abstract: Ultracold atoms in optical lattices are an ideal platform for simulating correlated many-body quantum systems that are at the heart of many condensed matter phenomena. We experimentally study the 2D non-equilibrium dynamics of effective spin-1/2 bosons in an optical lattice following a global quench from an initially antiferromagnetically ordered state. Using a highly controllable, checkerboard optical lattice, we continuously tune from a tunneling-dominated regime to a regime where magnetic superexchange dominates, despite the presence of lattice vacancies. We observe timescales over three orders of magnitude that are in good agreement with simple theoretical estimates, though the detailed dynamics of this system remain out of reach of current computational techniques.
CSS 2400
College Park, MD 20742