# CavityCavityInteraction

`class boulderopal.superconducting.CavityCavityInteraction(cavity_names, cross_kerr_coefficient)`

Class that stores all the physical system data for the interaction between two cavities.

### Parameters

**cavity_names**(*tuple**[**str**,**str**]*) – The two names identifying the cavities in the interaction.**cross_kerr_coefficient**(*real**or**np.ndarray**or**RealOptimizableSignal**or**RealOptimizableConstant*) – The cross-Kerr coefficient between the two cavities, $K_{12}$. If not provided, it defaults to no cross-Kerr term.

### SEE ALSO

`boulderopal.superconducting.Cavity`

: Class describing cavities in superconducting systems.

## Notes

The Hamiltonian for the interaction is defined as

$H_\mathrm{cavity-cavity} = K_{12} a_1^\dagger a_1 a_2^\dagger a_2 .$