Multi-Tone Bogoliubov Parametric Amplifier using a superconducting Bose-Hubbard dimer, Part 2: Experiment

In standing-wave amplifiers, gain is commonly generated by driving the device into an instability regime, which decreases its response time and leads to the characteristic gain-bandwidth tradeoff. This inherent limitation presents a challenge for practical applications, as the amplifier’s bandwidth scales with the square root of its power gain. So-called Bogoliubov amplifiers offer an alternative to overcome this limitation, where the application of multiple driving tones activates different parametric processes and is able to provide high gain while keeping the dynamical stability of the system [1]. Here, we present the realization of an optimally imbalanced Bogoliubov amplifier using the cross-Kerr interactions in a granular aluminum Bose-Hubbard dimer [2]. By driving the amplifier with two and three tones, we report an improvement in the gain-bandwidth scaling by factors of 6 and 10, respectively, for gains above 20 dB.

[1] A. Metelmann. et al., arXiv 2208.00024 (2022)

[2] N. Zapata. et al., arXiv 2403.10669 (2024)