  Rydberg atom-based sensors are a new type of radio frequency sensor that is
inherently quantum mechanical. Several configurations of the sensor use a local
oscillator to determine the properties of the target radio frequency field. We
explain how the physics of Rydberg atom-based sensors in two or more radio
frequency fields can be precisely described by a multiply dressed
Jaynes-Cummings model. Studying Rydberg atom-based sensors in two or more near
resonant radio frequency fields is important for understanding how interfering
signals as well as the local oscillator can affect measurements. Studies, so
far, focus on a simplified approximation for the local oscillator-target field
interaction that uses an analogy to radio frequency heterodyning. The atom acts
as a medium for exchanging electromagnetic field excitations of the field modes
whose spectrum is a ladder. The Jaynes-Cummings states and their avoided
crossings can be used to determine the properties of the radio frequency
fields. Radio frequency field sensitivity enhancement for non-resonant radio
frequencies is achieved and self-calibrated measurements are recovered under
specific conditions described by the theory.
