Abstract
We present a scalable architecture for the exploration of interacting topological phases of photons in arrays of microwave cavities, using established techniques from cavity and circuit quantum electrodynamics. A time-reversal symmetry-breaking (nonreciprocal) flux is induced by coupling the microwave cavities to ferrites, allowing for the production of a variety of topological band structures including the Hofstadter model. To induce photon-photon interactions, the cavities are coupled to superconducting qubits; we find these interactions are sufficient to stabilize a bosonic Laughlin puddle. Exact diagonalization studies demonstrate that this architecture is robust to experimentally achievable levels of disorder. These advances provide an exciting opportunity to employ the quantum circuit toolkit for the exploration of strongly interacting topological materials.
- Received 10 May 2016
DOI:https://doi.org/10.1103/PhysRevX.6.041043
Published by the American Physical Society under the terms of the Creative Commons Attribution 3.0 License. Further distribution of this work must maintain attribution to the author(s) and the published article’s title, journal citation, and DOI.
Published by the American Physical Society
Physics Subject Headings (PhySH)
Popular Summary
Placing a magnet in the beam of a flashlight simply results in a shadow, as expected. However, here we propose a way to cause the magnetic field to deflect the photons into circular orbits while inducing them to collide with one another. We demonstrate that this regime is analogous to an exciting phase of solids called a topological fluid, in which the excitations on the fluid surface can act as the qubits of a future topological quantum computer. By making such a topological fluid out of photons rather than electrons, we expect to be able to directly “shine light” on the system and reveal aspects of topological fluids that electrons have kept hidden.
We consider arrays of three-dimensional microwave cavities coupled by connecting their edges with waveguides. Topological phases of photons can exist in these cavities. We induce photon-photon interactions and a time-reversal symmetry-breaking (nonreciprocal) flux, which is not intrinsic to light, by coupling the cavity to a ferrite system. To this end, we place a ferrite sphere at the center of the cavity. Doing so results in cavity modes with specific angular momenta. We simulate our system numerically, and we find that it is insensitive to the largest sources of disorder. Because the individual components of our setup have already been realized in the lab (e.g., metal cavities, lattices with low disorder), we are confident that our proposal is experimentally feasible.
We expect that our findings will pave the way for future studies of topological many-body physics and spin-orbit coupling.