Accelerating axionic dark matter searches through remote entanglement of microwave cavities*

Quantum metrology using superconducting circuits has found a natural application in the search for ultralight dark matter, in particular the QCD axion. The scan rate for cavity-based axionic dark matter searches is fundamentally limited by quantum noise. We propose a method to increase the scan rate using a two-cavity setup, in which the axion cavity is coupled to an auxiliary readout cavity by simultaneous two-mode squeezing and state-swapping interactions. We show analytically that by matching the rates of these interactions, we can achieve intracavity single-quadrature amplification of the axion signal before it is polluted by noise from outside the cavity, thereby increasing the scan rate by increasing tuning step size. This talk will discuss progress towards a prototype experiment in which we expect to achieve amplification corresponding to 20x scan rate enhancement and numerical modeling in the service of extending the concept to real operating haloscopes.