Quantum Computation with Superconducting Qubits

  • Continuous qubit trajectories
    In circuit QED we infer the state of a quantum bit (qubit) by making a quadrature measurement on an interacting microwave resonator field. Achieving high-fidelity state-tracking from the collected noisy quadrature signal is a necessary prerequisite for more sophisticated quantum information tasks.

Superconducting transmon quantum bits are measured via their dispersive interaction with a neighboring microwave resonator.
Superconducting transmon quantum bits are measured via their dispersive interaction with a neighboring microwave resonator.
The interaction produces a state-dependent phase shift of a continuous microwave field. This phase shift can be detected as a continuous but noisy voltage signal using a homodyne measurement of the leaked and reflected microwave field.
The interaction produces a state-dependent phase shift of a continuous microwave field. This phase shift can be detected as a continuous but noisy voltage signal using a homodyne measurement of the leaked and reflected microwave field.

Filtering the noisy voltage signal reconstructs the stochastic quantum state evolution influenced by the continuous observation, known as a quantum trajectory.
Filtering the noisy voltage signal reconstructs the stochastic quantum state evolution influenced by the continuous observation, known as a quantum trajectory.

Quantum Information and Measurement Theory

Foundations of Physics

Funding Sources

 
 
 
 
 
NSF
NSF-BSF: Efficiently Modeling Continuous Quantum Measurements of High-Dimensional Multi-Qubit Systems
Sep 2019 – Present
NSF-BSF Grant Award No. 1915015
PI: Dr. Justin Dressel, Chapman University
BSF Collaborator: Dr. Lev Vaidman, University of Tel Aviv, Israel
Award amount: $321,000
Award end date: Aug 2023
 
 
 
 
 
ARO/LPS
Implementation of Novel Benchmarking and Error Management Protocols in Planar Transmon Processors
Jul 2018 – Present
Army Research Office (ARO) Grant Award No. W911NF-18-1-0178
PI: Dr. Irfan Siddiqi, University of California, Berkeley
Co-PI: Dr. Justin Dressel, Chapman University
Co-PI: Dr. Andrew N. Jordan, University of Rochester / Chapman University
Co-PI: Dr. Joseph Emerson, University of Waterloo
Subcontract amount: $546,328
Award end date: Sep 2022
 
 
 
 
 
ARO/LPS
Continuous Quantum State Tracking and Error Correction (CQSTEC)
Jul 2015 – Jun 2018
Army Research Office (ARO) Grant Award No. W911NF-15-1-0496
PI: Dr. Irfan Siddqi, University of California, Berkeley
Co-PI: Dr. Justin Dressel, Chapman University
Co-PI: Dr. Andrew N. Jordan, University of Rochester
Co-PI: Dr. Alexander N. Korotkov, University of California, Riverside
Subcontract amount: $300,000