Erlangen 2018 – scientific programme
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A: Fachverband Atomphysik
A 5: Cold atoms II - interactions (joint session A/Q)
A 5.3: Talk
Monday, March 5, 2018, 11:00–11:15, K 2.019
Commensurate-Incommensurate Transition in Optical Cavities — •Andreas Alexander Buchheit1, Haggai Landa2, Cecilia Cormick3, Thomas Fogarty4, Eugene Demler5, and Giovanna Morigi1 — 1Saarland University, 66123 Saarbrücken — 2IPhT, CEA Saclay, France — 3IFEG, CONICET and Universidad Nacional de Cordoba — 4Okinawa Institute of Science and Technology, Japan — 5Department of Physics, Harvard University, Cambridge, MA 02138, USA
We theoretically analyse the equilibrium configuration of an ion chain which interacts with the optical lattice of a cavity mode. We assume the lattice periodicity is almost commensurate with the interparticle distance of the ions and determine the resulting configuration as a function of their ratio. In the limit of small cooperativity, when cavity backaction is negligible, we show that this system simulates the commensurate-incommensurate phase transition. We derive a field theory for the kinks that are created in the incommensurate phase and determine the effects of the Coulomb repulsion on the phase diagram. When instead the cavity strongly couples to the ions motion we show that the commensurate-incommensurate transition becomes of first order and is associated with bistable behaviour of the cavity field. We characterize the kinks and their interactions and determine the properties of the light at the cavity output across the phase transition.