Coherent excitation of a two-state system by a Lorentzian field

Abstract:We study the coherent excitation of a two-state quantum system by a field with a Lorentzian temporal envelope and constant carrier frequency. The associated differential equation admits an exact local representation in terms of confluent Heun functions. For the transition probability we develop a Dykhne-Davis-Pechukas (DDP) description based on the two relevant complex transition points and their interference. The DDP action is analyzed directly in the weak- and strong-coupling limits, yielding explicit asymptotic expressions for the oscillation phase, oscillation envelope, far-detuned line shape, and near-resonant behavior. In particular, the strong-coupling asymptotics imply a linewidth proportional to the inverse peak Rabi frequency for resonant odd-$\pi$ pulses, thereby exhibiting the power-narrowing characteristic of the Lorentzian pulse.

arXiv:2607.27466 [quant-ph]

(or arXiv:2607.27466v1 [quant-ph] for this version)

https://doi.org/10.48550/arXiv.2607.27466 Focus to learn more arXiv-issued DOI via DataCite (pending registration)

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