Date: October 13, 2009 -
Time: 4:15 pm -

Stanford University
APPLIED PHYSICS/PHYSICS COLLOQUIUM

Tuesday, October 13, 2009
4:15 p.m. on campus in Hewlett Teaching Center, Rm. 201
Refreshments in the Physics Lobby at 4:00 p.m.

Professor Irfan Siddiqi
University of California, Berkeley

"Quantum Noise in Josephson's 'Frictionless' Pendulum"

The Josephson junction is a unique electrical oscillator which is both non-dissipative and non-linear at temperatures well below the superconducting transition temperature TC. The equations which describe the dynamics of the junction have the same form as that of a driven physical pendulum. I will show how this anharmonicity enables the realization of sensitive digital and analog amplifiers operating at the quantum limit of sensitivity. Moreover, vanishing internal dissipation reduces backaction and makes such amplifiers particularly well suited to quantum measurements.