Tutte Colloquium - Alicia Kollár

Friday, April 9, 2021 3:30 pm - 3:30 pm EDT (GMT -04:00)

Title: Circuit QED Lattices: Synthetic Quantum Systems on Line Graphs

Speaker: Alicia Kollár
Affliliation: University of Maryland
Zoom: Contact Emma Watson


After two decades of development, superconducting circuits have emerged as a rich platform for quantum computation and simulation. Lattices of coplanar waveguide (CPW) resonators realize artificial photonic materials or photon-mediated spin models. Here I will highlight the special property that these lattice sites are deformable and allow for the implementation of devices with graph-like configurational flexibility. In particular, I will show that it is possible to create synthetic materials in which microwave photons experience negative curvature, which is impossible in conventional electronic materials [1]. Furthermore, I will show that the one-dimensional nature of CPW resonators naturally implements line graphs and that lattices can be designed which host a spectrally-isolated degenerate set of compact-support localized eigenfunctions [2]. Finally, I will present joint work with Peter Sarnak where we show that the spectral gaps possible in these types of systems are limited in size, but not in location [2,3].

[1] Kollar, Fitzpatrick, Houck, Nature 45, 571 (2019).

[2] Kollar, Fitzpatrick, Sarnak, Houck, Comm. Math. Phys. 376, 1909-1956 (2020).

[3] Kollar, Sarnak, arXiv:2005.05379 (2020)