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Physics Colloquium - Dr Nicholas Lambert

Monday, 8 April 2019

Physics Department

Dr Nicholas Lambert

Research Fellow

Department of Physics

University of Otago

"Detecting microwaves with superconducting nanostructures"

Superconducting circuits have remarkable properties, including engineered non-linearities, low losses and field tunable energy landscapes, that allow them to be used as qubits, quantum limited amplifiers and detectors. They are typically operated at temperatures below 100 mK, using a dilution refrigerator and exploiting the exotic properties of He-3. Both measurement and control of the circuits can be established using high frequency electrical techniques, allowing sensitive and high bandwidth measurements of a device's impedance. In this talk, I will describe radio-frequency reflectometry measurements of a superconducting nanostructure that allow us to probe its charge state with ~10 kHz bandwidth and observe the breaking of Cooper pairs in real time. By controlling the state of the device, we demonstrate sensitivity to single microwave photons, with a controllable photon energy threshold. We then carry out spectroscopy on thermal sources within our cryogenic environment.

WHEN: Monday 8 April 2019
WHERE: Room 314, Science 3 Building
TIME: 3.00 pm–4.00 pm

All interested are welcome to attend

Light refreshments to follow in Common Room