St Dngz - Academia.edu (original) (raw)

Papers by St Dngz

Cotton flow tends to evolve a given initial metric on a three manifold to a conformally flat one.... more Cotton flow tends to evolve a given initial metric on a three manifold to a conformally flat one. Here we expound upon the earlier work on Cotton flow and study the linearized version of it around a generic initial metric by employing a modified form of the DeTurck trick. We show that the flow around the flat space, as a critical point, reduces to an anisotropic generalization of linearized KdV equation with complex dispersion relations one of which is an unstable mode, rendering the flat space unstable under small perturbations. We also show that Einstein spaces and some conformally flat non-Einstein spaces are linearly unstable. We refine the gradient flow formalism and compute the second variation of the entropy and show that generic critical points are extended Cotton solitons. We study some properties of these solutions and find a Topologically Massive soliton that is built from Cotton and Ricci solitons. In the Lorentzian signature, we also show that the pp-wave metrics are bo...

International Journal of Modern Physics A, 2018

In this note, we go over the recent soft photon model and Faddeev–Jackiw quantization of the mass... more In this note, we go over the recent soft photon model and Faddeev–Jackiw quantization of the massless quantum electrodynamics in the eikonal limit to some extent. Throughout our readdressing, we observe that the gauge potentials in both approaches become pure gauges and the associated eikonal Faddeev–Jackiw quantum bracket matches with the soft quantum bracket. These observations and the fact that the gauge fields in two cases localize in two-dimensional plane (even if it is spatial in soft photon case and (1[Formula: see text]+[Formula: see text]1)-dimensional Minkowski in the eikonal case) imply that there might be an interesting relation between these two distinct perspectives.

In this work, two particular orthogonal and conformal decompositions of the 3+1 dimensional Einst... more In this work, two particular orthogonal and conformal decompositions of the 3+1 dimensional Einstein equation and Arnowitt-Deser-Misner (ADM) formalism for general relativity are obtained. In order to do these, the 3+1 foliation of the four-dimensional spacetime, the fundamental conformal transformations and the Hamiltonian form of general relativity that leads to the ADM formalism, defined for the conserved quantities of the hypersurfaces of the globally-hyperbolic asymptotically flat spacetimes, are reconstructed. All the calculations up to chapter 7 are just a review. We propose a method in chapter 7 which gives an interesting relation between the Cotton (Conformal) soliton and the static vacuum solutions. The formulation that we introduce can be extended to find the gradient Cotton soliton and the solutions of Topologically Massive Gravity (TMG) as well as the gradient Ricci soliton.

Weyl-invariant extensions of three-dimensional New Massive Gravity, generic n-dimensional Quadrat... more Weyl-invariant extensions of three-dimensional New Massive Gravity, generic n-dimensional Quadratic Curvature Gravity theories and three-dimensional Born-Infeld gravity theory are analyzed in details. As required by Weyl-invariance, the actions of these gauge theories do not contain any dimensionful parameter; therefore the local symmetry is spontaneously broken in (Anti) de Sitter vacua in analogy with the Stan-dard Model Higgs mechanism. About the flat vacuum, symmetry breaking mechanism is more complicated: The conformal symmetry is radiatively broken (at two loop level in 3-dimensions and at one-loop level in 4-dimensions) a ̀ la Coleman-Weinberg mecha-nism and hence the dimensionful parameters come from “dimensional transmutation” in the quantum field theory. In the broken phases, save for New Massive Gravity, the theories generically propagate with a unitary (tachyon and ghost-free) massless tensor, massive (or massless) vector and massless scalar particles for the particular ...

Ivan Kolář, ∗ Tomáš Málek, † Suat Dengiz, ‡ and Ercan Kilicarslan § Van Swinderen Institute, Univ... more Ivan Kolář, ∗ Tomáš Málek, † Suat Dengiz, ‡ and Ercan Kilicarslan § Van Swinderen Institute, University of Groningen, 9747 AG, Groningen, Netherlands Institute of Mathematics of the Czech Academy of Sciences, Žitná 25, 115 67 Prague 1, Czech Republic Department of Mechanical Engineering, University of Turkish Aeronautical Association, 06790 Ankara, Turkey Department of Mathematics, Usak University, 64200, Usak, Turkey (Dated: July 27, 2021)

Physical Review D, 2021

We study the generalized minimal massive gravity (GMMG) in Compere, Song and Strominger (CSS) bou... more We study the generalized minimal massive gravity (GMMG) in Compere, Song and Strominger (CSS) boundary conditions employing a semi-product of a Virasoro and a û(1) KacMoody current algebras as the asymptotic symmetry algebra. We calculate the entropy of BTZ black holes via the degeneracy of states belonging to a Warped-CFT. We compute the linearized energy excitations by using the representations of the algebra û(1) × SL(2, R)R and show that energies of excitations are non-negative at (two) chiral points in the parameter space. At these special points, the charge algebra is described by either Virasoro algebra or Kac-Moody algebra. We also consider some special limits of the GMMG theory which correspond to 2 + 1-dimensional massive gravity theories such as new massive and minimal massive gravity theories.

arXiv: High Energy Physics - Theory, 2015

TURKISH JOURNAL OF PHYSICS, 2018

arXiv: General Relativity and Quantum Cosmology, 2011

The European Physical Journal C

In this work, we perform a holographic analysis to study non local observables associated to a un... more In this work, we perform a holographic analysis to study non local observables associated to a uniformly boosted strongly coupled large N thermal plasma in d-dimensions. In order to accomplish the holographic analysis, the appropriate dual bulk theory turns out to be d+1$$d+1 dimensional boosted AdS-Schwarzschild blackhole background. In particular, we compute entanglement entropy of the boosted plasma at high temperature living inside a strip geometry with entangling width l in the boundary at a particular instant of time. We also study the two-point correlators in the boundary by following geodesic approximation method. For analyzing the effect of boosting on the thermal plasma and correspondingly on both non local observables, we keep the alignment of the width of region of interest both parallel and perpendicular to the direction of the boost. We find our results significantly modified compared to those in un-boosted plasma up to the quadratic order of the boost velocity v. Mo...

Classical and Quantum Gravity

We construct and study perturbative unitarity (i.e., ghost and tachyon analysis) of a 3 + 1-dimen... more We construct and study perturbative unitarity (i.e., ghost and tachyon analysis) of a 3 + 1-dimensional noncompact Weyl-Einstein-Yang-Mills model. The model describes a local noncompact Weyl's scale plus SU (N) phase invariant Higgs-like field, conformally coupled to a generic Weyl-invariant dynamical background. Here, the Higgs-like sector generates the Weyl's conformal invariance of system. The action does not admit any dimensionful parameter and genuine presence of de Sitter vacuum spontaneously breaks the noncompact gauge symmetry in an analogous manner to the Standard Model Higgs mechanism. As to flat spacetime, the dimensionful parameter is generated within the dimensional transmutation in quantum field theories, and thus the symmetry is radiatively broken through the one-loop Effective Coleman-Weinberg potential. We show that the mere expectation of reducing to Einstein's gravity in the broken phases forbids anti-de Sitter space to be its stable vacua. The model is unitary in de Sitter and flat vacua around which a massless graviton, N 2 − 1 massless scalar bosons, N massless Dirac fermions, N 2 − 1 Proca-type massive Abelian and non-Abelian vector bosons are generically propagated.

The European Physical Journal C, 2016