Quantum simulation of ultrastrongly coupled bosonic modes using superconducting circuits

Understand

The ground state of a pair of ultrastrongly coupled bosonic modes is predicted to be a two-mode squeezed vacuum.

• However, the corresponding quantum correlations are currently unobservable in condensed matter where such a coupling can be reached, since it cannot be extracted from these systems.
• Here, we show that superconducting circuits can be used to perform an analog simulation of a system of two bosonic modes in regimes ranging from strong to ultrastrong coupling.
• More importantly, our quantum simulation setup enables us to detect output excitations that are related to the ground-state properties of the bosonic modes.