Santos, A. C. L., Muniz, C. R., & Maluf, R. V. (2023). Yang-Mills Casimir wormholes in D=2+1. J. Cosmol. Astropart. Phys., 09(9), 022–24pp.
Abstract: This work presents new three-dimensional traversable wormhole solutions sourced by the Casimir density and pressures related to the quantum vacuum fluctuations in Yang-Mills (Y-M) theory. We begin by analyzing the noninteracting Y-M Casimir wormholes, initially considering an arbitrary state parameter omega and determine a simple constant wormhole shape function. Next, we introduce a new methodology for deforming the state parameter to find well-behaved redshift functions. The wormhole can be interpreted as a legitimate Casimir wormhole with an expected average state parameter of omega = 2. Then, we investigate the wormhole curvature properties, energy conditions, and stability. Furthermore, we discover a novel family of traversable wormhole solutions sourced by the quantum vacuum fluctuations of interacting Yang-Mills fields with a more complex shape function. Deforming the effective state parameter similarly, we obtain well-behaved redshift functions and traversable wormhole solutions. Finally, we examine the energy conditions and stability of solutions in the interacting scenario and compare to the noninteracting case.
|
Agius, D., Essig, R., Gaggero, D., Scarcella, F., Suczewski, G., & Valli, M. (2024). Feedback in the dark: a critical examination of CMB bounds on primordial black holes. J. Cosmol. Astropart. Phys., 07(7), 003–36pp.
Abstract: If present in the early universe, primordial black holes (PBHs) would have accreted matter and emitted high-energy photons, altering the statistical properties of the Cosmic Microwave Background (CMB). This mechanism has been used to constrain the fraction of dark matter that is in the form of PBHs to be much smaller than unity for PBH masses well above one solar mass. Moreover, the presence of dense dark matter mini -halos around the PBHs has been used to set even more stringent constraints, as these would boost the accretion rates. In this work, we critically revisit CMB constraints on PBHs taking into account the role of the local ionization of the gas around them. We discuss how the local increase in temperature around PBHs can prevent the dark matter mini -halos from strongly enhancing the accretion process, in some cases significantly weakening previously derived CMB constraints. We explore in detail the key ingredients of the CMB bound and derive a conservative limit on the cosmological abundance of massive PBHs.
|
Galli, P., Goldstein, K., Katmadas, S., & Perz, J. (2011). First-order flows and stabilisation equations for non-BPS extremal black holes. J. High Energy Phys., 06(6), 070–28pp.
Abstract: We derive a generalised form of flow equations for extremal static and rotating non-BPS black holes in four-dimensional ungauged N = 2 supergravity coupled to vector multiplets. For particular charge vectors, we give stabilisation equations for the scalars, analogous to the BPS case, describing full known solutions. Based on this, we propose a generic ansatz for the stabilisation equations, which surprisingly includes ratios of harmonic functions.
|
Galli, P., Goldstein, K., & Perz, J. (2013). On anharmonic stabilisation equations for black holes. J. High Energy Phys., 03(3), 036–7pp.
Abstract: We investigate the stabilisation equations for sufficiently general, yet regular, extremal (supersymmetric and non-supersymmetric) and non-extremal black holes in four-dimensional N = 2 supergravity using both the H-FGK approach and a generalisation of Denef's formalism. By an explicit calculation we demonstrate that the equations necessarily contain an anharmonic part, even in the static, spherically symmetric and asymptotically flat case.
|
Galli, P., Ortin, T., Perz, J., & Shahbazi, C. S. (2013). Black-hole solutions of N=2, d=4 supergravity with a quantum correction, in the H-FGK formalism. J. High Energy Phys., 04(4), 157–37pp.
Abstract: We apply the H-FGK formalism to the study of some properties of a general class of black holes in N = 2 supergravity in four dimensions that correspond to the harmonic and hyperbolic ansatze and we obtain explicit extremal and non-extremal solutions for the t(3) model with and without a quantum correction. Not all solutions of the corrected model (quantum black holes), including in particular a solution with a single q(1) charge, have a regular classical limit.
|