Dr. Kevin D. Osborn

Laboratory for Physical Sciences

8050 Greenmead Dr.

College Park, MD  20740

Lab Phone: 301-935-6415

Reception: 301-935-6400

Facsimile: 301-935-6723

 

KDO Research Group

Superconducting Quantum Computing and Low Temperature Physics

By cooling circuits 10,000 times closer to absolute zero than room temperature entire circuits enter quantum mechanical states, where quantized energy levels dictate their properties, and anharmonic oscillator circuits behave like  artificial atoms. While atomic wavefunctions describe the position of electrons near a nucleus, those of superconducting circuits are used to described the state of circuit quantities, e.g., currents and voltages. Two different wave functions are used to describe a quantum bit or qubit in quantum computing studies. Particularly in this group we have studied additional tunneling states that appear in these circuits, which are known to limit the performance. Following quantum device studies, new circuits are developed either to ameliorate quantum phenomena that hinder quantum computing or exploit phenomena that can be advantageous.

A qubit defect is individually probed in a thick film for the first time, and the circuits (one example above) use cavity quantum electrodynamics (CQED). The use of CQED with superconducting qubits was pioneered by researchers at Yale U., and here we extend it to tunneling two-level systems in capacitors.