Probing the dissipation process via a Fano resonance and collective effects in an x-ray cavity

In the absence of time-reversal symmetry, the asymmetric parameter q of the Fano resonance is extended into the complex space, where its trajectory can be utilized to investigate the decoherence process. By embedding the ensemble of Mossbauer nuclei in the thin-film planar cavity in this work, the trajectories of asymmetric parameter q are studied via the collective effect of the nuclear ensemble, which is regulated by the nuclear abundance and angle offset. Due to the diverse controllable methods of the collective resonant strength, there are different straight lines and arc-shaped trajectories in the complex plane, in which the slopes and the radius can be adjusted by the angle offset and nuclear abundance, respectively. It is demonstrated that the dissipation process can be "suppressed" equivalently by the strong energy exchange between the cavity and the nuclear ensemble. The present results could enrich the behaviors of the asymmetric parameter q in the complex plane and would provide a new opportunity for decoherence research through the thin-film planar cavity.