Intermode Dephasing in a Superconducting Stripline Resonator

TL;DR

This paper investigates how a superconducting stripline resonator with an integrated SQUID exhibits flux-dependent intermode dephasing of microwave photons due to Kerr nonlinearity, supported by experimental and theoretical analysis.

Contribution

It demonstrates experimentally and theoretically how SQUID-induced Kerr nonlinearity causes flux-dependent intermode dephasing in superconducting resonators.

Findings

Dephasing rate varies periodically with magnetic flux.

Maximum dephasing occurs at half-integer flux quanta.

Good agreement between experiment and theory.

Abstract

We study superconducting stripline resonator (SSR) made of Niobium, which is integrated with a superconducting interference device (SQUID). The large nonlinear inductance of the SQUID gives rise to strong Kerr nonlinearity in the response of the SSR, which in turn results in strong coupling between different modes of the SSR. We experimentally demonstrate that such intermode coupling gives rise to dephasing of microwave photons. The dephasing rate depends periodically on the external magnetic flux applied to the SQUID, where the largest rate is obtained at half integer values (in units of the flux quantum). To account for our result we compare our findings with theory and find good agreement. Supplementary info at arXiv:0901.3133 .