Here, you will find my latest research on superconducting quantum circuits!
My main area of interest is on quantum computing systems, with emphasis on implementations based on superconducting circuits. The main focus is on the experimental realization of practical quantum technologies as well as understanding the underlying quantum science; selected theoretical studies complete my research topics. Superconducting devices comprise simple harmonic oscillators, such as on-chip resonators, as well as effective quantum-mechanical two-level states, quantum bits or qubits. Superconducting qubits have proven as one of the leading candidates toward the physical realization of a practical quantum computer (see, e.g., the recent Google 53-qubit work on quantum supremacy). Building a practical quantum computer requires advanced applied physics and systems engineering, where nontrivial wiring and packaging methods and classical-to-quantum control and measurement systems must be implemented with minimal disturbance to the qubits in large qubit arrays.
At the UW, my team and I fabricated state-of-the-art on-chip superconducting resonators and frequency-tunable Xmon transmon qubits with internal quality factors Qi~1 M in the quantum regime and energy relaxation times T1~20 μs, respectively. Using such devices, we were able to reach randomized benchmarking fidelities F>99.9% for one-qubit gates. In 2015, we were the first group worldwide to develop a fully vertical interconnect wiring and packaging method – the quantum socket. Additionally, we experimentally realized spatially demultiplexed qubit control schemes that, combined with existing frequency multiplexed measurements, will make it possible to reduce the number of wires for Xmon transmon qubits from three wires per qubit to just two wires every ten qubits.
