Britton Plourde: Superconducting resonators for quantum information science: loss and amplification

Monday, October 25, 2010 12:30 pm - 1:30 pm EDT (GMT -04:00)

Britton Plourde, Syracuse University

One of the more promising systems for forming a quantum computer architecture in the solid state involves superconducting tunnel junction circuits, which play the role of atoms, and microwave resonators, which provide a pathway for transmitting and storing quanta in the form of microwave photons. I will describe several ongoing efforts in my research group focused on such superconducting microwave resonant circuits. In a quest to improve the quality factor of these resonators and thus extend their lifetime for preserving quantum states, we are investigating different loss mechanisms. Vortices, which are quantized bundles of magnetic flux, trapped in a superconducting resonator lead to increased loss. In addition, the native surface oxides that are present on many superconducting thin films can limit resonator quality factors. I will discuss strategies we are pursuing to understand these loss mechanisms as we strive to develop higher performance superconducting resonators. We are also working to develop amplifiers for measuring the quantum state of these resonators more efficiently than is possible with existing technology. These amplifiers are based on superconducting circuits and the amount of noise they add to a measurement promises to approach the limit imposed by quantum mechanics.