University of Minnesota
School of Physics & Astronomy

Physics and Astronomy Calendar

Wednesday, February 15th 2017
1:25 pm:
Speaker: Brian Zhou, Institute for Molecular Engineering, University of Chicago
Subject: Shaping the quantum dynamics of single spins in diamond
Candidate for the Condensed Matter Experimental Assistant Professor Position

The appearance of quantum mechanics on the macroscopic scale underlies some of the most fascinating phenomena in condensed matter physics: topological states arising from Berry phases in electronic bands, and superconductivity from many-body entanglement. Recently, advances in the control and coherence of microscopic quantum systems have enabled these fundamental quantum effects to be studied at the single or few-particle level, as well as be leveraged towards new paradigms for information processing. In this talk, I will focus on experiments using one such system, an atomic-scale defect in diamond known as the nitrogen-vacancy (NV) center. Behaving as a solid-state ‘trapped atom’, the NV center possesses spin and orbital levels, isolated within the host semiconductor’s bandgap, that can be readily manipulated with optical and microwave fields. Through resonant optical excitation, we demonstrate that the NV center spin can be adiabatically evolved to point along arbitrary loops and acquire a Berry phase after the cycle. Such precise quantum control sheds insights on the robustness of geometric phase. Moreover, we accelerate adiabatic dynamics and minimize decoherence by using engineered optical pulses to construct ‘shortcuts’ that absorb deleterious transitions. Finally, I will overview how combining optical and electrical techniques at the atomic level can contribute to applications of material systems in computing, energy, and sensing.

Faculty Host: James Kakalios

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