We are a device research group focusing on solid-state systems for advancing quantum computation, communication and sensing. We study a wide range of physical systems including superconducting quantum circuits, color centers, integrated photonics and phononics. Our central goal is to develop the building blocks for scalable quantum technologies that leverage semiconductor manufacturing methods. Our projects present a balance of fundamental and applied research related to solid-state quantum devices. We develop integrated microwave, acoustic, and photonic systems to realize new architectures for future quantum technologies, and use these systems to gain new insights into quantum dynamics and coherence in nanoscale systems. 

We are a highly interdisciplinary group with students and postdoctoral fellows from electrical engineering, physics, materials science, and chemistry departments. We are always looking for talented students and postdocs to join our group. 

Current research directions:

Integrated photonic quantum repeaters with silicon spin-photon interfaces:

Illustration of a silicon photonic crystal array containing quantum emitters. Device credit: Lukasz Komza, 2023

Silicon is the ideal material platform for building electronic and photonic circuits at scale. We are developing quantum nonlinear silicon photonics that will enable deterministic interactions between single photons and spin qubits for quantum communication and computation. To achieve this, we are developing spin-photon interfaces in integrated silicon photonics. The questions we study include: 

  • Color center qubits in silicon: How do we design an “ideal” atom-like, color center qubit in silicon? What are the desired defect symmetries, spin, electronic and optical properties? This is our defect genome project
  • Device integration: Integration of artificial atoms into silicon photonics to realize deterministic spin-photon, photon-photon, and long range spin-spin interactions at high bandwidths. 
  • Quantum repeater nodes: Developing a practical quantum repeater node based on silicon color centers for the UC Berkeley – LBL Quantum Network Testbed. 

Our long-term vision is to develop the missing ingredients that would enable practical quantum computers and communication nodes at silicon foundries. 

Phononics to advance superconducting quantum technologies:

Phonon- and defect- engineered superconducting qubits. Device credit: Mutasem Odeh, 2023

Superconducting quantum circuits are currently the leading solid-state quantum computing platform. Despite their remarkable progress, we are yet to fully understand and control dominant dissipation mechanisms that lead to high physical qubit error rates. In the past few years, the new field of quantum phononics has shown that single phonons can be coherently controlled and can make great qubits! We found that nanomechanical resonators can have ultra long lifetimes, and can be used to transduce quantum states from superconducting qubits to optical photons. We are building on these recent advances in quantum phononics to advance superconducting quantum technologies via phonon- and defect- engineering. The topics we study include:

  • Materials origins of qubit-phonon interactions
  • Coherence in electromechanical quantum systems, defect-qubit-phonon interactions
  • Develop phonon-protected superconducting qubits
  • Efficient, low-noise quantum transduction between superconducting qubits, phonons, single spins, and optical photons
  • Ultrahigh frequency quantum phononics

Please check out our publications and recent recorded talks (2023, 2021) to learn more about our work.