From smooth curves to universal metrics

Sisman, Tahsin Cagri
Tekin, Bayram
A special class of metrics, called universal metrics, solves all gravity theories defined by covariant field equations purely based on the metric tensor. Since we currently lack the knowledge of what the full quantum-corrected field equations of gravity are at a given microscopic length scale, these metrics are particularly important in understanding quantum fields in curved backgrounds in a consistent way. However, finding explicit universal metrics has been a difficult problem as there does not seem to be a procedure for it. In this work, we overcome this difficulty and give a construction of universal metrics of d-dimensional spacetime from curves constrained to live in a (d - 1)-dimensional Minkowski spacetime or a Euclidean space.


Öcal, Sultan Eylül; Tekin, Bayram; Kılıçarslan, Ercan; Department of Physics (2021-8)
Infinite Derivative Gravity (IDG) is a modified gravity theory which can avoid the singularities and Ultraviolet problem of gravity. This thesis examines the effects of IDG on these problems. First, the propagators and Newtonian potential will be examined as well as the conditions necessary for avoidance of singularities for perturbations around Minkowski background are found. Second, we study the exact pp-wave and AdS-plane wave solutions of quadratic and Infinite derivative gravity theories. We construct ...
Kerr-Schild-Kundt metrics are universal
GÜRSES, METİN; Sisman, Tahsin Cagri; Tekin, Bayram (IOP Publishing, 2017-04-06)
We define (non-Einsteinian) universal metrics as the metrics that solve the source-free covariant field equations of generic gravity theories. Here, extending the rather scarce family of universal metrics known in the literature, we show that the Kerr-Schild-Kundt class of metrics are universal. Besides being interesting on their own, these metrics can provide consistent backgrounds for quantum field theory at extremely high energies.
BULUTAY, C; PRASAD, S (1993-06-01)
Three-dimensional condensed asymmetrical node, variable grid, transmission-line matrix (TLM) method has been used in analyzing several millimeter waveguides on anisotropic substrates. The dispersion characteristics of image guides together with field and energy confinement properties at millimeter-wave frequencies have been investigated. Edge coupled microstrip line on a uniaxial substrate is analyzed for the even and odd mode dispersion characteristics. Finally the same analysis is repeated for bilateral f...
On the energy-momentum in closed universes
Salti, M (Springer Science and Business Media LLC, 2006-02-01)
Using the Moller, Einstein, Bergmann-Thomson and Landau-Lifshitz energy-momentum definitions both in general relativity and teleparallel gravity, we find the energy-momentum of the closed universe based on the generalized Bianchi-I type metric.
A Survey on Spacetime Geometries and Relativistic Models
Okutmuştur, Baver (null; 2019-12-23)
Our analysis starts with the flat geometry, so-called Minkowski spacetime, and follows by further generalizations on specific spherically symmetric geometries whose metric elements describe solutions to the Einstein’s field equation. Next the relativistic models originated from the conservation form of the energy momentum tensor relation on these particular examples of spacetime geometries are presented. Finally we introduce certain properties of these models of interests and hence provide a conclusion ...
Citation Formats
M. GÜRSES, T. C. Sisman, and B. Tekin, “From smooth curves to universal metrics,” PHYSICAL REVIEW D, pp. 0–0, 2016, Accessed: 00, 2020. [Online]. Available: