Discriminating coherent states superpositions by line shapes

This article investigates the effect of near non-resonant levels on the spectral lines of atoms interacting with an electromagnetic field. Specifically, we examine the AC Stark effect that occurs when the field frequency matches the transition frequency between two lower levels and the field has a small average number of photons ($\mathrm{\mid }\alpha {\mathrm{\mid }}^2<4$). Our research demonstrates that the changes in spectral line shape can be used to distinguish between Schrödinger cat states with opposite phases in $\pi$, namely, the states $\mathrm{\mid }\alpha ⟩+\mathrm{\mid }-\alpha ⟩$ and $\mathrm{\mid }\alpha ⟩-\mathrm{\mid }-\alpha ⟩$.