Physics Department Colloquium

Laser cooled trapped ions offer unprecedented control over both internal and external degrees of freedom at the single-particle level. They are considered among the foremost candidates for realizing quantum simulation and computation platforms that can outperform classical computers at specific tasks. In this talk I will show how linear arrays of trapped 171Yb+ ions can be used as a versatile platform for studying quantum dynamics of strongly correlated many-body quantum systems.

Measurements of the fine-structure constant alpha require methods from several subfields and are thus powerful tests of the consistency of theory and experiment in physics. Using the recoil frequency of cesium-133 atoms in a matter-wave interferometer, we recorded the most accurate measurement of the fine-structure constant to date: alpha = 1/137.035999046(27) at 2.0 x 10^-10 accuracy.

The ability to engineer controllable atom-photon interactions is at the heart of quantum optics and quantum information processing. In this talk, I will introduce a nanophotonic platform for engineering strong atom-photon interactions on a semiconductor chip. I will first discuss an experimental demonstration of a spin-photon quantum transistor [1], a fundamental building block for quantum repeaters and quantum networks. The device allows a single spin trapped inside a semiconductor quantum dot to switch a single photon, and vice versa, a single photon to flip the spin.

Abstract: Cooling atomic gases to quantum degeneracy opened the new field of quantum simulation. Here the precise tools of atomic physics can be used to study exotic models from condensed matter or nuclear physics with unique tunability and control. Ultracold molecules bring many new possibilities to quantum simulation. I will review the physics of ultracold molecules, including our recent production of stable, ultracold triplet molecules and what they can add to quantum simulation.