# Research Projects

## Circuit Quantum Electrodynamics

Microwave photons in a superconducting transmission line cavity are strongly coupled to a qubit, or "artificial atom," in direct analogy with optical cavity QED. This a key component of everything we do, including superconducting quantum computing, hybrid quantum inofrmation, and quantum simulation.

## Hybrid Quantum Computing

We are interested in coupling superconducting resonators to other (non-superconducting) quantum systems. We are particularly focused on coupling to electron spin qubits in collaboration with other members of the Princeton Center for Complex Materials.

## Condensed matter physics with photons

Photons do not in general interact. However, in a cavity QED system, a qubit can mediate an effective interaction between photons. In coupled arrays of such cQED elements, photons can hop between neighboring cavities and experience on-site interactions in any one cavity. Such arrays are expected to support many-body states of photons and interesting matter-like behavior. Because photon number is not a conserved quantity, such behavior is far from equilibrium and an area of particular interest.

## Superconducting Quantum Computation

We explore superconducting qubits for purposes of quantum computation, focusing on improved elements of a quantum computer rather than implementation of small algorithms. In particular, we are focused on new types of qubits, including a transmon-like qubit with tunable coupling, and improved measurement.