where Ω n = 2ℏg c √ n + 1 is the n th Rabi frequency (which is the Rabi splitting under the resonant condition when ∆Eℏω c = 0). Note that when the lightmatter detuning (∆Eℏω c ) is zero, sin Θ = cos Θ = 1/ √ 2, and E ± (n) = E g + ℏω c (n + 3/2) ± Ω n /2. This is the resonance case, which is schematically depicted in Fig. for the n = 0 case. A full diagram of JC polariton eigenstates with all n is commonly referred to as the Jaynes-Cummings ladder (eg, see Fig. 1 in Ref. 17). In the JC model, the difference in energy between the upper and lower polariton states is called the "Rabi splitting"