Steven Girvin

Prof. Steven Girvin

Eugene Higgins Professor of Physics

Circuit QED: Non-linear quantum optics and quantum information processing with microwave photons and artificial atoms

‘Circuit quantum electrodynamics’ is the theory of non-linear quantum optics extended to the study of microwave photons strongly interacting with ‘artificial atoms’ (Josephson junction qubits) embedded in superconducting electrical circuits. Roy Glauber taught us how to understand destructive photo-detection events in which the absorption of an optical photon triggers a photomultiplier. Recent remarkable experimental progress now allows us to make quantum non-demolition (QND) measurements of microwave photon number as well as photon number parity and super-parity. These advances in our ability to measure and manipulate the quantum states of microwaves are leading to novel applications ranging from accelerating dark matter searches to quantum error correction that has successfully extended the lifetime of quantum information. It is also now possible to use QND boson-sampling techniques to carry out quantum simulations of the vibronic sidebands in the optical spectra of molecules. This talk will present an elementary introduction to the basic concepts underlying circuit QED and describe several recent novel experiments demonstrating these newfound capabilities.