Tunable and nonlinearity-enhanced dispersive-plus-dissipative coupling in photon-pressure circuits.

Kazouini, Mohamad; Peter, Janis; Guo, Zisu Emily; Wilde, Benedikt; Uhl, Kevin; Koelle, Dieter; Kleiner, Reinhold; Bothner, Daniel · Nat Commun · 2026

basic_science · Level V

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Abstract

Photon-pressure circuits are the circuit implementation of the cavity optomechanical Hamiltonian and discussed for qubit readout, low-frequency quantum photonics and dark matter axion detection. Due to the enormous design flexibility of superconducting circuits, photon-pressure systems provide fascinating possibilities to explore unusual parameter regimes of the optomechanical Hamiltonian. Here, we report the realization of a photon-pressure platform, in which a GHz circuit interacts with a MHz circuit via a magnetic-flux-tunable combination of dispersive and dissipative photon-pressure. In addition, both coupling rates are considerably enhanced by nonlinearities of the GHz-mode, which leads to the multi-photon coupling rates scaling stronger with the pump photon number n<sub>c</sub> than the usual <math xmlns="http://www.w3.org/1998/Math/MathML"> <msqrt> <mrow> <msub><mrow><mi>n</mi></mrow> <mrow><mi>c</mi></mrow> </msub> </mrow> </msqrt> </math> dependence. We demonstrate that interference of the two interaction paths leads to a Fano-like response in photon-pressure induced transparency, and that the dynamical backaction is considerably modified compared to the dispersive case, including a parametric instability caused by a red-detuned pump tone.