Department of Applied Physics and Materials Science - Applied Physics

IQIM Postdoctoral and Graduate Student Seminar

Friday September 25, 2015 4:00 PM

Strongly interacting photons in a synthetic magnetic field

Speaker: Pedram Roushan, Google Inc., Santa Barbara
Location: East Bridge 114

Abstract: Interacting electrons in the presence of magnetic fields exhibit some of the most fascinating phases in condensed matter systems. Realizing these phases in an engineered platform could provide deeper insight into their nature and the potential for harnessing their unique properties for computation. In quantum systems whose excitations are bosonic, achieving such a platform would require introducing interactions between bosons and generating fields analogous to magnetic fields in fermionic systems. Using three superconducting qubits, we synthesize gauge fields by rapidly modulating the inter-qubit coupling. In the closed loop formed by the qubits, we observe the circulation of an excited state as well as chiral spin-currents in the groundstate, the signatures of broken time-reversal symmetry.  The existence of strong interactions in our system is seen via the creation of photon vacancies, or "holes", which circulate in the opposite direction from the photons. Our work demonstrates an experimental approach for realizing strongly correlated phases of matter, such as the fractional quantum-hall states, in bosonic systems and takes a major step toward realizing them.

Series Applied Physics Seminar Series

Contact: Marcia Brown at 626-395-4013 marciab@caltech.edu