From Analogue Models to Gravitating Vacuum
Abstract
We discuss phenomenology of quantum vacuum. Phenomenology of macroscopic systems has three sources: thermodynamics, topology and symmetry. Momentum space topology determines the universality classes of fermionic vacua. The vacuum in its massless state belongs to the Fermipoint universality class, which has topologically protected fermionic quasiparticles. At low energy they behave as relativistic massless Weyl fermions. Gauge fields and gravity emerge together with Weyl fermions at low energy. Thermodynamics of the selfsustained vacuum allows us to treat the problems related to the vacuum energy: the cosmological constant problems. The natural value of the energy density of the equilibrium the selfsustained vacuum is zero. Cosmology is the process of relaxation of vacuum towards the equilibrium state. The present value of the cosmological constant is very small compared to the Planck scale, because the present Universe is very old and thus is close to equilibrium.
 Publication:

arXiv eprints
 Pub Date:
 November 2011
 DOI:
 10.48550/arXiv.1111.1155
 arXiv:
 arXiv:1111.1155
 Bibcode:
 2011arXiv1111.1155V
 Keywords:

 General Relativity and Quantum Cosmology;
 Condensed Matter  Other Condensed Matter;
 High Energy Physics  Phenomenology
 EPrint:
 35 pages, 5 figures, prepared for Proceedings of the II Amazonian Symposium on Physics  Analogue Models of Gravity: 30 Years Celebration of the publication of Bill Unruh's paper "Experimental BlackHole Evaporation?"