Quantum-dot spin qubits
Our research is primarily focused on developing quantum computing hardware based on lithographically-defined Si/SiGe quantum dot devices. One can make a quantum bit (qubit) out of all sorts of different systems: photons trapped in superconductors, vibrations in nanoscale systems, or even impurities in diamond. In our lab, we make qubits using the spins of individual electrons trapped in silicon.
To do this, we fabricate nanoscale devices in the Quattrone Nanofabrication Facility in the Singh Center for Nanotechnology and cool them down to below 10 milliKelvin (that's -459.7 degrees Fahrenheit!). The devices are then used to isolate and control individual electrons by applying a series of electrical and microwave pulses. Our devices offer a direct probe into quantum mechanical effects that are often non-intuitive given the length scales over which we interact with our environment. By studying the dynamics of these quantum mechanical systems, we hope to not only glean insight into fundamental laws of physics, but also develop tools based on quantum effects that can have a positive impact on society. Quantum computers promise to revolutionize nearly every field, from logistics to weather modeling to drug discovery and materials development. Simply put, our group aims to use lithographically defined quantum dots to build the hardware necessary for these exciting applications.
Quantum engineering is a multidisciplinary field, and students gain experience in nanofabrication, programming, electronic circuit design, cryogenics engineering, and microwave engineering. If you're interested in joining our team, please reach out!
Scaling-up silicon quantum processors
While studies in few-qubit devices teach us a lot about how to make and control quantum processors, we believe that it is important to keep an eye to the future. Ultimately, the fundamental quantum hardware must be scalable and we are rethinking device architectures to enable that scalability.
Novel quantum control approaches
There are a variety of ways to encode and control electron spin qubits and it is not yet clear what approach affords the best scalability and control fidelity. We are looking to find better ways to control quantum processors by developing new primitive quantum gates and modes of operation.
Engineering the qubit environment
A lot of work has gone into engineering the isotopic composition of silicon semiconductors to support long coherence times. We are interested in exploring new host materials and studying the effect of residual impurities.