"Progress towards Studying Quantum Many-Body Physics in Circuit QED Lattices," by Will Shanks (Princeton University)

Monday, September 30, 2013 - 11:00am to 12:00pm
AMO Seminars


AMO Seminar

Monday, September 30
Physics & Astronomy Building (PAB) Room 4-330

Guest Speaker: Will Shanks, Princeton University, Department of Electrical Engineering

Talk Title: "Progress towards Studying Quantum Many-Body Physics in Circuit QED Lattices"


Coupling a qubit to an electromagnetic resonator induces a non-linearity in the energy spectrum of the system.  Denoting the excitations of the system as "polaritons," this non-linearity can be viewed as an effective polariton-polariton interaction.  In recent years, theorists have studied the consequences of this interaction in multi-resonator systems (Jaynes-Cummings lattices) and have predicted interesting effects which include analogs to the superfluid-Mott insulator transition and the fractional quantum Hall effect.  I will describe our efforts towards building Jaynes-Cummings lattices using the circuit QED architecture.  We have studied small-scale (12 resonator) lattices in order to understand and reduce disorder resulting from imperfections in device fabrication.  At this time, it is not clear that straightforward transmission measurements will be sufficient to investigate fully the quantum many-body states within a circuit QED lattice.  With this in mind, we have begun developing a scanning tool to serve as a local probe of the circuit QED lattice.  I will describe the results of scanning a transmon qubit over a single superconducting coplanar waveguide resonator, including observation of strong coupling and reasonable qubit coherence.  I will also present preliminary results from scanning a defect over a lattice with 49 resonators.