CPT symmetric universe


Boyle, L. (2018). CPT symmetric universe. Perimeter Institute. https://pirsa.org/18040100


Boyle, Latham. CPT symmetric universe. Perimeter Institute, Apr. 03, 2018, https://pirsa.org/18040100


          @misc{ pirsa_18040100,
            doi = {},
            url = {https://pirsa.org/18040100},
            author = {Boyle, Latham},
            keywords = {Cosmology},
            language = {en},
            title = {CPT symmetric universe},
            publisher = {Perimeter Institute},
            year = {2018},
            month = {apr},
            note = {PIRSA:18040100 see, \url{https://pirsa.org}}


I will introduce our recent proposal that the state of the universe does *not* spontaneously violate CPT. Instead, the universe before the Big Bang is the CPT reflection of the universe after the bang. Phrased another way, the universe before the bang and the universe after the bang may be re-interpreted as a universe/anti-universe pair, created from nothing. CPT selects a unique vacuum state for the QFT on such a spacetime, which leads to a new perspective on the cosmological baryon asymmetry, and a new explanation for the observed dark matter abundance. In particular, if we assume that the matter fields in the universe are described by the standard model of particle physics (including right-handed neutrinos), we predict that one of the heavy neutrinos is stable, and that its density automatically matches the observed dark matter density if its mass is 4.8 x 10^8 GeV. Among other predictions, we have: (i) that the three light neutrinos are majorana; (ii) that the lightest of these is exactly massless; and (iii) that there are no primordial long-wavelength gravitational waves. I will mention connections to the strong CP problem and the arrow of time. (Based on arXiv:1803.08928 and arXiv:1803.08930, with Kieran Finn and Neil Turok.)