99 citations · 371 across the 23 of their papers we have counts for
23 papers
Quantum Suppression of Mass Inflation in Reissner-Nordström Interiors via Wheeler-DeWitt Equation
Chen-Hsu Chien, Woosung Song, Gansukh Tumurtushaa +1
We construct a canonical quantization, the Wheeler-DeWitt equation, of the interior geometry of static and spherically symmetric black holes in Einstein-Maxwell- framework, focu…
Implications of pulsar timing arrays for Gauss-Bonnet Inflation
Reginald Christian Bernardo, Seoktae Koh, Gansukh Tumurtushaa
Correlated time-of-arrival measurements by pulsar timing arrays (PTAs) have provided a new means of constraining astrophysical or cosmological models that produce a gravitational w…
Higgs Inflation with a Gauss-Bonnet term
Seoktae Koh, Seong Chan Park, Gansukh Tumurtushaa
Higgs inflation with a Gauss-Bonnet term is studied in the Einstein frame. Our model features two coupling functions, and , coupled to the Ricci scalar and Gauss-Bon…
Existence of gradient CKV and gradient conformally stationary LRS spacetimes
Seoktae Koh, Abbas M Sherif, Gansukh Tumurtushaa
In this work, we study the existence of gradient (proper) CKVs in locally rotationally symmetric spacetimes (LRS), those CKVs in the space spanned by the tangent to observers' cong…
Dynamical Compactification with Matter
Kyung Kiu Kim, Seoktae Koh, Gansukh Tumurtushaa
In this work, we study cosmological solutions of the 8-dimensional Einstein Yang-Mills theory coupled to a perfect-fluid matter. A Yang-Mills instanton of extra dimensions causes a…
Wheeler-DeWitt equation beyond the cosmological horizon: Annihilation to nothing, infinity avoidance, and loss of quantum coherence
Chen-Hsu Chien, Gansukh Tumurtushaa, Dong-han Yeom
We investigate the Schwarzschild-(anti) de Sitter spacetime with the anisotropic metric ansatz. The Wheeler-DeWitt equation for such a metric is solved numerically. In the presence…
Dynamical analysis in regularized Einstein-Gauss-Bonnet gravity with non-minimal coupling
Bilguun Bayarsaikhan, Sunly Khimphun, Phearun Rithy +1
We investigate the regularized four-dimensional Einstein-Gauss-Bonnet ( EGB) gravity with a non-minimal scalar coupling function, which is an extension of the regularized …
The reheating constraints to natural inflation in Horndeski gravity
Chen-Hsu Chien, Seoktae Koh, Gansukh Tumurtushaa
For the subclass of Horndeski theory of gravity, we investigate the effects of reheating on the predictions of natural inflation. In the presence of derivative self-interaction of…
Primordial black holes and induced gravitational waves from inflation in the Horndeski theory of gravity
Pisin Chen, Seoktae Koh, Gansukh Tumurtushaa
We investigate the production of primordial black holes (PBHs) and scalar-induced gravitational waves (GWs) for cosmological models in the Horndeski theory of gravity. The cosmolog…
Observational Constraints on the Cosmology with Holographic Dark Fluid
Da Huang, Bum-Hoon Lee, Gansukh Tumurtushaa +2
We consider the holographic Friedman-Robertson-Walker (hFRW) universe on the 4-dimensional membrane embedded in the 5-dimensional bulk spacetime and fit the parameters with the obs…
Generalized Holographic Cosmology: low-redshift observational constraint
Sunly Khimphun, Bum-Hoon Lee, Gansukh Tumurtushaa
Four-dimensional cosmological models are studied on a boundary of a five-dimensional Anti-de Sitter (AdS_5) black hole with AdS Reissner-Nordstrom and scalar charged Reissner- Nord…
Euclidean wormholes in Gauss-Bonnet-dilaton gravity
Xiao Yan Chew, Gansukh Tumurtushaa, Dong-han Yeom
We investigate Euclidean wormholes in Gauss-Bonnet-dilaton gravity to explain the creation of the universe from nothing. We considered two types of dilaton couplings (i.e., the str…
Constraints on dark energy models from the Horndeski theory
Bilguun Bayarsaikhan, Seoktae Koh, Enkhbat Tsedenbaljir +1
In light of the cosmological observations, we investigate dark energy models from the Horndeski theory of gravity. In particular, we consider cosmological models with the derivativ…
The viable f(G) gravity models via reconstruction from the observations
Seokcheon Lee, Gansukh Tumurtushaa
We reconstruct the viable f(G) gravity models from the observations and provide the analytic solutions that well describe our numerical results. In order to avoid unphysical challe…
Trans-Planckian censorship and single-field inflaton potential
Kenji Kadota, Chang Sub Shin, Takahiro Terada +1
It was recently proposed that a field theory cannot be consistent with quantum gravity if it allows a mode shorter than the Planck length to exit the Hubble horizon. This is called…
Inflation with Derivative Self-interaction and Coupling to Gravity
Gansukh Tumurtushaa
We consider a subclass of Horndeski theories for studying cosmic inflation. In particular, we investigate models of inflation in which the derivative self-interaction of the scalar…
Emergent Dark Universe and the Swampland Criteria
Rong-Gen Cai, Sunly Khimphun, Bum-Hoon Lee +3
We study a model of the emergent dark universe, which lives on the time-like hypersurface in a five-dimensional bulk spacetime. The holographic fluid on the hypersurface is assumed…
The high temperature crossover for general 2D Coulomb gases
Gernot Akemann, Sung-Soo Byun
We consider particles in the plane influenced by a general external potential that are subject to the Coulomb interaction in two dimensions at inverse temperature . At large…
Constraints on the Reheating Parameters after Gauss-Bonnet Inflation from the Primordial Gravitational Waves
Seoktae Koh, Bum-Hoon Lee, Gansukh Tumurtushaa
We study the effects of the Gauss-Bonnet term on the energy spectrum of inflationary gravitational waves. The models of inflation are classified into two types based on their predi…
Reconstruction of the Scalar Field Potential in Inflationary Models with a Gauss-Bonnet term
Seoktae Koh, Bum-Hoon Lee, Gansukh Tumurtushaa
We study inflationary models with a Gauss-Bonnet term to reconstruct the scalar field potentials and the Gauss-Bonnet coupling functions from the observable quantities. Using the o…
Observational constraints on inflation with the nonlinear sigma fields in light of Plank 2015
Seoktae Koh, Bum-Hoon Lee, Gansukh Tumurtushaa
We study an inflation model with a nonlinear sigma field which has symmetry. The background solution of the nonlinear sigma field is proportional to the space coordinates l…
Primordial gravitational waves from the space-condensate inflation model
Seoktae Koh, Bum-Hoon Lee, Gansukh Tumurtushaa
We consider the space-condensate inflation model to study the primordial gravitational waves generated in the early Universe. We calculate the energy spectrum of gravitational wave…
Observational constraints on slow-roll inflation coupled to a Gauss-Bonnet term
Seoktae Koh, Bum-Hoon Lee, Wonwoo Lee +1
We study slow-roll inflation with a Gauss-Bonnet term that is coupled to an inflaton field nonminimally. We investigate the inflationary solutions for a specific type of the nonmin…