For approximately two decades researchers have studied superconducting qubits (quantum bits) which, along with other technologies, has led to substantial advancement in quantum information science. Superconducting qubits utilize macroscopic-quantum coherence (two engineered quantized levels from a condensate). In this group custom superconducting resonators and qubits reveal new understandings of coherence, material phenomena with quantum properties, novel quantum systems, et cetera, for the future of computing. Many studies are performed on atomic-sized two-level systems (TLSs) in materials, a major source of decoherence in qubits. Ongoing projects perform TLS-energy tuning and TLS-sourced microwave lasing (see publications). In other studies, macroscopic-quantum phenomena with flux-quanta are explored to lower the energy usage and heat dissipation of digital gates in computers. In this latter project, irreversible functions will be replaced with reversible ones using novel dynamics of specific fluxons which have topological-particle properties. The new gates are ballistic and induce flux polarity inversion (topological charge change) using negligible kinetic energy (see updates).

In this device, an spectrally isolated qubit defect is probed using strong cavity quantum electrodynamics (C-QED) for the first time. The defect is atomic-sized and it resides in a ~100 nm thick film. These defects have two-levels and are being probed in an array of custom circuits in the group. In other work we have introduced dc electric-field tuning of the defect energy. The phenomena of lasing is also shown to be enabled with these random, but tunable, defects.

KDO Research Group

Kevin D. Osborn, Ph.D.

Laboratory for Physical Sciences at the University of Maryland

8050 Greenmead Dr.

College Park, MD  20740

osborn -at- lps -dot- umd -dot- edu

Superconducting circuits with two quantized levels or quantized flux for quantum and reversible computing