Cosmology from quantum gravity condensates

TY - GEN

T1 - Cosmology from quantum gravity condensates

AU - Pithis, Andreas Georg Aristides

AU - Sakellariadou, Maria

PY - 2016/12

Y1 - 2016/12

N2 - We analyze relationally evolving and effectively interacting Group Field Theory (GFT) models in the context of the GFT quantum gravity condensate analogue of the Gross-Pitaevskii equation for real Bose-Einstein condensates (BEC). More precisely, we firstly study the expectation value of the volume operator imported from Loop Quantum Gravity (LQG) in an isotropic restriction in the static case of a free and then interacting condensate system. In both cases one finds a nonvanishing condensate population for which the expectation value is dominated by the lowest nontrivial configurations of the quantum geometry. This indicates that the condensate consists of many smallest building blocks giving rise to an effectively continuous geometry, which suggests the interpretation of the condensate phase to correspond to a geometric phase. In a second step, we study the relational evolution of the such condensate systems with respect to a relational clock and demonstrate that from their effective dynamics the classical Friedmann equation can be recovered, thus reproducing and generalizing earlier obtained results by other authors.

AB - We analyze relationally evolving and effectively interacting Group Field Theory (GFT) models in the context of the GFT quantum gravity condensate analogue of the Gross-Pitaevskii equation for real Bose-Einstein condensates (BEC). More precisely, we firstly study the expectation value of the volume operator imported from Loop Quantum Gravity (LQG) in an isotropic restriction in the static case of a free and then interacting condensate system. In both cases one finds a nonvanishing condensate population for which the expectation value is dominated by the lowest nontrivial configurations of the quantum geometry. This indicates that the condensate consists of many smallest building blocks giving rise to an effectively continuous geometry, which suggests the interpretation of the condensate phase to correspond to a geometric phase. In a second step, we study the relational evolution of the such condensate systems with respect to a relational clock and demonstrate that from their effective dynamics the classical Friedmann equation can be recovered, thus reproducing and generalizing earlier obtained results by other authors.

U2 - 10.6084/m9.figshare.4312619.v1

DO - 10.6084/m9.figshare.4312619.v1

M3 - Other contribution

ER -