Dynamical Couplings, Dynamical Vacuum Energy and Confinement/Deconfinement from R^2-Gravity

Abstract

We study within Palatini formalism an f(R)-gravity with f(R)= R + αR^2 interacting with a dilaton and a special kind of nonlinear gauge field system containing a square-root of the standard Maxwell term, which is known to produce confinement in flat space-time. Reformulating the model in the physical Einstein frame we find scalar field effective potential with a flat region where the confinement dynamics disappears, while in other regions it remains intact. The effective gauge couplings as well as the induced cosmological constant become dynamical. In particular, a conventional Maxwell kinetic term for the gauge field is dynamically generated even if absent in the original theory. We find few interesting classes of explicit solutions: (i) asymptotically (anti-)de Sitter black holes of non-standard type with additional confining vacuum electric potential even for the electrically neutral ones; (ii) non-standard Reissner-Nordstroem black holes with additional constant vacuum electric field and having non-flat-spacetime "hedgehog" asymptotics; (iii) generalized Levi-Civitta-Bertotti-Robinson "tube-like" space-times.

16 pages

References in corpus (7)

• Palatini Approach to Modified Gravity: f(R) Theories and Beyond
• Dynamical Aspects of Generalized Palatini Theories of Gravity
• The dynamics of generalized Palatini Theories of Gravity
• Confinement from spontaneous breaking of scale symmetry
• Static potential from spontaneous breaking of scale symmetry
• Bags and Confinement Governed by S.S.B. of Scale Invariance
• Strong Interaction Dynamics from Spontaneous Symmetry Breaking of Scale Invariance

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• Nonsingular electrovacuum solutions with dynamically generated cosmological constant
• Equivalent off-diagonal cosmological models and ekpyrotic scenarios in f(R)-modified, massive and Einstein gravity
• Gravitational and topological effects on $\sqrt{-F^2}$ Confinement Dynamics
• Charge-Confining Gravitational Electrovacuum Shock Wave
• Gravity, Nonlinear Gauge Fields and Charge Confinement/Deconfinement