## Colliding photons and instantons in superconducting circuits

**Speaker:**Vladimir Manucharyan

**When:**November 13, 2020 (Fri), 12:00PM to 01:00PM (add to my calendar)

*This event is part of the Biophysics/Condensed Matter Seminar Series. *

Light does not typically scatter light, as witnessed by the linearity of Maxwell's equations. Using linear chains of Josephson junctions, we constructed superconducting circuits, in which microwave photons have well-defined energy and momentum, but their lifetime is finite due to decay into lower energy photons. The inelastic photon-photon interaction originates from quantum phase-slip fluctuations and has no analogs in quantum optics. In fact, the surprisingly high photon decay rate is explained by mapping the system to a Luttinger liquid with impurities. In this talk I will introduce an electrical engineer's view of quantum phase-slips [1] and overview our recent experimental studies of photon-instanton collisions [2]. TIme permitting, I will discuss the relevance of our results in the contexts of quantum impurity models [3], quantum thermalization in closed systems, and superconductor-insulator transition in one-dimensional superconductors [4].

[1] arXiv:1907.02937 (Nature 2020) [2] arXiv:2010.02099 [3] arXiv:2010.02630 [4] arXiv:1805.07379 (Nature Physics 2019)