Microwave cavity memories for superconducting circuits
Quantum states in nonlinear superconducting circuits are short lived (they can survive a few hundred microseconds before decohering), but linear microwave resonators have lifetimes reaching hundred times more. The key question is then the following: can we control these long-lived resonators using short-lived circuits? To some extent, this is indeed possible and has one great advantage—we can use microwave resonators as memories for superconducting devices. I am trying to understand what are the best ways to do that and what limitations they have.
Key publication
Iivari Pietikäinen, Ondřej Černotík, Alec Eickbusch, Aniket Maiti, John W. O. Garmon, Radim Filip, and Steven M. Girivn, Strategies and trade-offs for controllability and memory time of ultra-high-quality microwave cavities in circuit quantum electrodynamics, PRX Quantum 5, 040307 (2024).
Hybridizing levitation with superconducting circuits
The strong nonlinearity of superconducting circuits can be used to impart nonlinear dynamics on systems which are otherwise linear. An interesting example are levitated systems (such as nanoparticles or individual ions). Their motion is very well isolated from any noise, making them great for sensing and other applications. To benefit from quantum effects, it is crucial to effect nonlinear control of this motion, which is difficult. I am trying to understand what are the optimal ways to couple levitated systems to superconducting circuits for nonlinear motional control and what interesting applications we can do with these systems.
Ondřej Černotík 