Studies of Superconductor flux qubits

Aluminium/aluminium oxide Josephsonjunctions flux qubits are fabricated at Royal Holloway. We have already demonstrated a new type of read-out device - an Andreev interferometer - and now we are performing spectroscopy measurements of the qubits [1]. These frequency domain measurements will make way to more testing time-domain measurements, where the fidelity (quality) of the qubit can be directly measured. The next step will be to design and fabricate new superconducting circuits to explore entanglement. The research is based in the Nanophysics group at Royal Holloway where there are state-of-the-art cleanrooms and measurement facilities. A new dilution fridge with a base temperature of 10 mK will be dedicated to these new experiments, allowing more RF lines and space for low-temperature amplifiers, filters, circulators, etc., to be positioned close to the sample.

We are looking for PhD students who would like to learn new experimental skills both in the cleanroom and in the measurement lab. The experimental work involves both individual and team skills, and is well suited to those with a broad understanding of quantum mechanics and solid-state physics.

[1] "Andreev probe of persistent current states in superconducting quantum circuits" V. T. Petrashov, K. G. Chua, K. M. Marshall, R. Sh. Shaikhaidarov, and J. T. Nicholls, Phys. Rev. Lett. 95, 147001 (2005).

 

For further information contact Dr James Nicholls or Professor Victor Petrashov.