Academic staff
Kofinas Georgios
Personal Information
Kofinas Georgios
Associate Professor
gkofinas [at] aegean [dot] gr
2273082238
Lymperis Building, B3
Friday 14:30-15:30
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Conference Publications
V. Zarikas, G. Kofinas, Singularities and Phenomenological aspects of Asymptotic Safe Gravity, 20th International Meeting: Physical Interpretations of Relativity Theory (PIRT 2017), July 2017, Moscow, Russia , J. Phys. Conf. Series 1051, no. 1, pp. 012028, 2018, https://iopscience.iop.org/article/10.10...
Abstract:
Asymptotic Safety (AS) Program for quantum gravity keeps the same fields and symmetries with General Relativity and studies the associated gravitational action as a fundamental part of the complete theory at the nonperturbative level with the help of functional renormalization group (RG) techniques. An important phenomenological task that can test the new point of view of AS approach is the discovery of RG improved cosmologies and black holes. In this work, we analyze the properties of recently found non-singular spherically symmetric and non-singular cosmological solutions. Furthermore, we derive a novel consistent set of modified Einstein field equations, in the spirit of AS, which respects the Bianchi identities. This new set of equations completes previously published modified Einstein equations which arise by adding appropriate covariant kinetic terms to the action.
Asymptotic Safety (AS) Program for quantum gravity keeps the same fields and symmetries with General Relativity and studies the associated gravitational action as a fundamental part of the complete theory at the nonperturbative level with the help of functional renormalization group (RG) techniques. An important phenomenological task that can test the new point of view of AS approach is the discovery of RG improved cosmologies and black holes. In this work, we analyze the properties of recently found non-singular spherically symmetric and non-singular cosmological solutions. Furthermore, we derive a novel consistent set of modified Einstein field equations, in the spirit of AS, which respects the Bianchi identities. This new set of equations completes previously published modified Einstein equations which arise by adding appropriate covariant kinetic terms to the action.
G. Kofinas, R. Olea, Universal Kounterterms in Lovelock AdS gravity, 3rd RTN Workshop: Constituents, fundamental forces and symmetries of the universe, Maria A. Lledo, (ed), pp. 957-963, Oct, 2007, Valencia, Spain, Fortschr. Phys. 56
Abstract:
We show the universal form of the boundary term (Kounterterm series) which regularizes the Euclidean action and background-independent definition of conserved quantities for any Lovelock gravity theory with AdS asymptotics (including Einstein-Hilbert and Einstein-Gauss-Bonnet). We discuss on the connection of this procedure to the existence of topological invariants and Chern-Simons forms in the corresponding dimensions.
We show the universal form of the boundary term (Kounterterm series) which regularizes the Euclidean action and background-independent definition of conserved quantities for any Lovelock gravity theory with AdS asymptotics (including Einstein-Hilbert and Einstein-Gauss-Bonnet). We discuss on the connection of this procedure to the existence of topological invariants and Chern-Simons forms in the corresponding dimensions.
[1]
G. Kofinas, E. Papantonopoulos, V. Zamarias, Braneworlds with induced gravity, Recent developments in gravity, K.D. Kokkotas, N. Stergioulas, (eds), 2003, Chalkidiki, Greece, World Scientific