author = "Tamayo, D. A. and Lima, J. A. S. and Alves, M{\'a}rcio E. S. and 
                         Ara{\'u}jo, Jos{\'e} Carlos Neves de",
          affiliation = "{Universidade de S{\~a}o Paulo (USP)} and {Universidade de 
                         S{\~a}o Paulo (USP)} and {Universidade Estadual Paulista (UNESP)} 
                         and {Instituto Nacional de Pesquisas Espaciais (INPE)}",
                title = "Primordial gravitational waves in running vacuum cosmologies",
              journal = "Astroparticle Physics",
                 year = "2017",
               volume = "87",
                pages = "18--22",
             keywords = "Cosmology, Gravitational waves, Relativity and gravitation, Wave 
                         generation and sources.",
             abstract = "We investigate the cosmological production of gravitational waves 
                         in a nonsingular flat cosmology powered by a running vacuum energy 
                         density described by \ρ\Λ \≡ 
                         \ρ\Λ(H), a phenomenological expression potentially 
                         linked with the renormalization group approach in quantum field 
                         theory in curved spacetimes. The model can be interpreted as a 
                         particular case of the class recently discussed by Perico et al. 
                         (2013) [25] which is termed complete in the sense that the cosmic 
                         evolution occurs between two extreme de Sitter stages (early and 
                         late time de Sitter phases). The gravitational wave equation is 
                         derived and its time-dependent part numerically integrated since 
                         the primordial de Sitter stage. The generated spectrum of 
                         gravitons is also compared with the standard calculations where an 
                         abrupt transition, from the early de Sitter to the radiation 
                         phase, is usually assumed. It is found that the stochastic 
                         background of gravitons is very similar to the one predicted by 
                         the cosmic concordance model plus inflation except at higher 
                         frequencies (\ν \≳ 100 kHz). This remarkable 
                         signature of a running vacuum cosmology combined with the proposed 
                         high frequency gravitational wave detectors and measurements of 
                         the CMB polarization (B-modes) may provide a new window to 
                         confront more conventional models of inflation.",
                  doi = "10.1016/j.astropartphys.2016.11.007",
                  url = "http://dx.doi.org/10.1016/j.astropartphys.2016.11.007",
                 issn = "0927-6505",
             language = "en",
           targetfile = "tamayo_primordial.pdf",
        urlaccessdate = "26 nov. 2020"