Enhancing the Dispersive Interaction between a Qubit and Squeezed Photons

The interaction strength of an oscillator to a qubit is proportional to its vacuum field fluctuations. The well known degenerate parametric oscillator has revived interest in the regime of strongly detuned squeezing, where its eigenstates are squeezed Fock states. Owing to these amplified fluctuations, it was recently proposed that such an oscillator, coined the Bogoliubov oscillator, would couple more strongly to a qubit. In a superconducting circuit experiment, we have observed that squeezing a Bogoliubov oscillator amplifies its dispersive coupling to a qubit. We measure a two-fold increase in the dispersive interaction strength at 5.5 dB of squeezing. This work initiates the experimental coupling of Bogoliubov oscillators to qubits, and cautiously motivates their dissemination in experimental platforms seeking enhanced interactions.