 Some attempt has also been made to go beyond the so-called rotating-wave approximation that is usually employed (see the mathematical derivation below).The coupling of a single quantum field mode with multiple (formula_3) two-state subsystems (equivalent to spins higher than 1/2) is known as the Dicke model or the Tavis–Cummings model.For example, it applies to a high quality resonant cavity containing multiple identical atoms with transitions near the cavity resonance, or a resonator coupled to multiple quantum dots on a superconducting circuit.