# TransmonCavityInteraction¶

The Boulder Opal Toolkits are currently in beta phase of development. Breaking changes may be introduced.

class TransmonCavityInteraction(dispersive_shift=None, rabi_coupling=None, transmon_name='transmon', cavity_name='cavity')

Class that stores all the physical system data for the interaction between a transmon and a cavity.

Parameters
• dispersive_shift (real or np.ndarray or RealOptimizableSignal or RealOptimizableConstant, optional) – The dispersive shift between the transmon and the cavity, $$\chi$$. You must provide either a dispersive shift or a Rabi coupling.

• rabi_coupling (real or complex or np.ndarray or RealOptimizableSignal or RealOptimizableConstant or ComplexOptimizableSignal or ComplexOptimizableConstant, optional) – The strength of the Rabi coupling between the transmon and the cavity, $$\Omega$$. You must provide either a dispersive shift or a Rabi coupling.

• transmon_name (str, optional) – The name identifying the transmon in the interaction. Defaults to “transmon”.

• cavity_name (str, optional) – The name identifying the cavity in the interaction. Defaults to “cavity”.

superconducting.Cavity

Class describing cavities in superconducting systems.

superconducting.Transmon

Class describing transmons in superconducting systems.

Notes

The Hamiltonian for the interaction is defined as

$H_\mathrm{transmon-cavity} = \chi a^\dagger a b^\dagger b ,$

or as

$H_\mathrm{transmon-cavity} = \Omega a b^\dagger + H.c. ,$

where $$H.c.$$ indicates the Hermitian conjugate.