Decoherence and Flux Noise in Fluxonium-based Qubits

When: 
Thursday, October 13, 2016 - 4:00pm to 5:00pm
Where: 
Allen Hall 321
O'Hara Street Pittsburgh PA 15260

Superconducting qubits are created by connecting Josephson junctions, which are non-linear, non-dissipative elements,to simple electrical circuits. In this talk, I will give a brief introduction to the fluxonium qubit, which is a Josephson junction connected to a superinductance. I will then introduce an artificial molecule, composed of two strongly coupled fluxonium atoms, which possesses a tunable magnetic moment. Using an applied external flux,we can tune the molecule between two regimes: one in which the ground-excited state manifold has a magnetic dipole moment and one in which the ground-excited state manifold has only a magnetic quadrupole moment. By varying the applied external flux, we find the coherence of the molecule to be limited by local flux noise.