Gauge ambiguities imply Jaynes-Cummings physics remains valid in ultrastrong coupling QED.

ABSTRACT: Ultrastrong-coupling between two-level systems and radiation is important for both fundamental and applied quantum electrodynamics (QED). Such regimes are identified by the breakdown of the rotating-wave approximation, which applied to the quantum Rabi model (QRM) yields the apparently less fundamental Jaynes-Cummings model (JCM). We show that when truncating the material system to two levels, each gauge gives a different description whose predictions vary significantly for ultrastrong-coupling. QRMs are obtained through specific gauge choices, but so too is a JCM without needing the rotating-wave approximation. Analysing a circuit QED setup, we find that this JCM provides more accurate predictions than the QRM for the ground state, and often for the first excited state as well. Thus, Jayn

SUBMITTER: Stokes A 

PROVIDER: S-EPMC6354024 | biostudies-literature | 2019 Jan

REPOSITORIES: biostudies-literature