Ivan Deutsch, University of New Mexico
Atomic spins are natural carriers of quantum information given their long coherence time and our capabilities to coherently control and measure them with magneto-optical fields. In this seminar I will describe two paradigms for quantum information processing with ensembles of spin in cold atoms. The strong electric dipole-dipole interactions arising when atoms are excited to high-lying Rydberg states is a powerful method for designing entangling interactions in neutral atoms. I will explore how adiabatic dressing of ground-state atoms with high-lying Rydberg states provides an avenue for further manipulation of nonclassical states based on the techniques of optimal control. By mapping a symmetrically-coupled Rydberg ensemble to the Jaynes-Cummings model, I will show how we can obtain arbitrary control of superpositions of collective Dicke states. Moreover, adiabatic dressing and quantum control can allow us to create high-fidelity entangling two-qubit gates, robust to random atomic motion at finite temperature, and other imperfections. In a second paradigm, atoms can be entangled through their mutual coupling to a common mode of the quantum electromagnetic field which acts as a quantum data bus. I will show how one can use this quantum data bus for measurement-based feedback to simulate nonlinear dynamics, quantum chaos, the quantum-to-classical transition, and quantum simulations of quantum many-body-dynamics.
Join us at 2:00 for refreshments and meet and greet with Dr. Deutsch