Relaño Pérez, ArmandoMolina, R. A.Retamosa Granado, JoaquínMuñoz Muñoz, LauraFaleiro, E.Gómez Gómez, José María2023-06-202023-06-202010Pérez-Fernández P, Relaño A, Arias J M, Dukelsky J and García-Ramos J E 2009 Decoherence due to an excited-state quantum phase transition in a two-level boson model Phys. Rev. A 80 0321111742-658810.1103/physreva.80.032111https://hdl.handle.net/20.500.14352/44419© 2010 IOP Publishing Ltd. Symposium on Nuclear Physics (33rd. 2010. Morelos, México). This research has been supported in part by Spanish Government grant No. FIS2009-07277 and No. FIS2006-12783-C03-02, CSPD-2007 00042-Ingenio2010, and by the Universidad Complutense de Madrid grant UCM-910059. A.R. is supported by the CPAN Consolider program.The power spectrum of the δ_(n) statistic of quantum spectra presents 1/ƒ^(α) noise. For chaotic systems α = 1 while for regular systems α = 2. Although the transition from regularity to chaos is non universal, for a wide variety of systems with a mixed phase space the value of α is intermediate between 1 and 2 and can be related to the fraction of regular or chaotic orbits in the total phase space. This statistic can be a very useful tool for the analysis of experimental spectra, specially in the case of missing levels or spectral sequences with mixed symmetries.engAtribución 3.0 Españahttps://creativecommons.org/licenses/by/3.0/es/journal articlehttp://dx.doi.org/10.1103/physreva.80.032111http://iopscience.iop.org/open access536Power SpectrumSymmetriesTermodinámica2213 Termodinámica