Current Research
Hybrid Quantum Systems with Electrons on Helium
The surface of superfluid helium at low temperatures functions as a fantastically pristine substrate without the defects and imperfections that are unavoidable in almost all other material systems. Electrons placed near this superfluid substrate become bound to it and float (in vacuum) about 10 nm above the surface. These electrons exhibit quantized motion relative to the surface that is predicted to be shielded from decoherence by the isolation provided by the superfluid environment. The interaction between electrons can be tuned by controlling their relative positions. This makes the electrons an ideal candidate for incorporation into hybrid quantum systems in which the electrons are coupled to other physical systems or quantum degrees of freedom with the goal of exploring new many-body quantum phenomena and to potentially develop novel quantum technologies.
Superconducting Circuits & Qubits
Superconducting circuit based qubits are micro-fabricated electrical circuits that exhibit quantum mechanical behavior, such as quantized energy levels, at temperatures near absolute zero. In many ways these qubits behave much like large artificial atoms whose quantum properties can be engineered, tuned and controlled. We are developing hybrid quantum systems by coupling these kinds of qubits to other quantum objects and degrees of freedom.
Nitrogen-Vacancy Centers in Diamond
Nitrogen-vacancy (NV) centers are atomic defects composed of a substitutional nitrogen atom next to a vacancy in the carbon lattice of diamond. The electrons forming the NV center act as an effective spin-1 system that can be operated as a qubit at room temperature via a combination of laser initialization & readout and microwave coherent control. Harnessing the exquisite sensitivity of the NV center to magnetic fields, we are developing hybrid systems based on NV centers coupled to exotic magnetic materials & quantum acoustic devices.
Quantum Phases of Matter in Low-Dimension Electron Systems
When electrons are confined to low spatial dimensionality, and subjected to extremely low temperature and high magnetic field, their collective behavior can lead to numerous exotic quantum phases of matter. These include electronic solids, liquid crystals, and even fluids consisting quasiparticles with fractional charge and fractional quantum statistics, just to name a few. Ultimately these phases of matter arise from the combination of quantum many-body effects and strong electron-electron interactions. These electronic states can now be realized in number of material systems ranging from graphene to layered semiconductor structures. What are the possibilities to engineer new quantum mechanical phases of matter in interacting many-body systems? Can we control the properties and interactions between the particles in these systems? Can we ultimately leverage our understanding to develop new disruptive quantum technologies? These are the kinds of questions we work to answer by studying these fascinating electronic systems.
