Bibekananda Nayak
@fmuniversity.nic.in
Assistant Professor, P. G. Department of Physics, Fakir Mohan University, Balasore, Odisha, 756019
Fakir Mohan University
RESEARCH, TEACHING, or OTHER INTERESTS
Nuclear and High Energy Physics, Astronomy and Astrophysics
Scopus Publications
Scholar Citations
Scholar h-index
Scholar i10-index
Scopus Publications
Biswanath Rath, Bibekananda Nayak, Pravanjan Mallick, Rati Ranjan Sahoo, Vedat Suat Erturk, Rania Wannan, Rabab Jarrar, Hussein Shanak, and Jihad Asad
SAGE Publications
We revisited the characteristic features of Yao-Cheng non-linear oscillator by employing both analytical as well as numerical approaches. Our study indicates that the solution of the non-linear oscillator shows oscillatory behaviour. Further, the phase portrait for this oscillator system reflects the closed loop signifying the stability of the system. Our results suggest the absence of damping in this physical system.
Suryakanta Swain, Debasis Sahu, Debabrata Dwivedee, Gourishankar Sahoo, and Bibekananda Nayak
Springer Science and Business Media LLC
Suraj Kumar Pati, Bibekananda Nayak, and Lambodar Prasad Singh
Springer Science and Business Media LLC
Bibekananda Nayak
Pleiades Publishing Ltd
Debasis Sahu and Bibekananda Nayak
Springer Singapore
S. Mahapatra and B. Nayak
Pleiades Publishing Ltd
D. Dwivedee, B. Nayak, and L. P. Singh
Springer Science and Business Media LLC
D. Dwivedee, B. Nayak, M. Jamil, L. P. Singh, and R. Myrzakulov
Springer Science and Business Media LLC
D. DWIVEDEE, B. NAYAK, and L. P. SINGH
World Scientific Pub Co Pte Lt
We investigate the evolution of primordial black hole mass spectrum by including both accretion of radiation and Hawking evaporation within Brans–Dicke (BD) cosmology in radiation-, matter- and vacuum-dominated eras. We also consider the effect of evaporation of primordial black holes on the expansion dynamics of the universe. The analytic solutions describing the energy density of the black holes in equilibrium with radiation are presented. We demonstrate that these solutions act as attractors for the system ensuring stability for both linear and nonlinear situations. We show, however, that inclusion of accretion of radiation delays the onset of this equilibrium in all radiation-, matter- and vacuum-dominated eras.
B. Nayak and L. P. Singh
Springer Science and Business Media LLC
Bibekananda Nayak and Mubasher Jamil
Elsevier BV
B. Nayak and L. P. Singh
Springer Science and Business Media LLC
B NAYAK and L P SINGH
Springer Science and Business Media LLC
B. Nayak and L. P. Singh
American Physical Society (APS)
We consider the evolution of primordial black holes by including non-stationarity in their formation process and accretion of radiation in Brans-Dicke theory. Specifically, we focus on how $\\eta$, the fraction of the horizon mass the black hole comprises capturing nonstationarity, affects the lifetimes of these primordial black holes. Our calculation reveals that the primordial black hole dynamics is controlled by the product $f\\eta$ where $f$ is the accretion efficiency. We also estimate the impact of $\\eta$ through $f\\eta$ on the primordial black holes' initial mass fraction constraint obtained from the $\\gamma$-ray background limit.
B Nayak, A.S Majumdar, and L.P Singh
IOP Publishing
We consider cosmological evolution in Brans-Dicke theory with a population of primordial black holes. Hawking radiation from the primordial black holes impacts various astrophysical processes during the evolution of the Universe. The accretion of radiation by the black holes in the radiation dominated era may be effective in imparting them a longer lifetime. We present a detailed study of how this affects various standard astrophysical constraints coming from the evaporation of primordial black holes. We analyze constraints arising from the present density of the Universe, the present photon spectrum, the distortion of the cosmic microwave background spectrum and also from processes affecting light element abundances after nucleosynthesis. We find that the constraints on the initial primordial black hole mass fractions are tightened with increased accretion efficiency.
B. Nayak, L. P. Singh, and A. S. Majumdar
American Physical Society (APS)
We consider the effect of accretion of radiation in the early Universe on primordial black holes in Brans-Dicke theory. The rate of growth of a primordial black hole due to accretion of radiation in Brans-Dicke theory is considerably smaller than the rate of growth of the cosmological horizon, thus making available sufficient radiation density for the black hole to accrete causally. We show that accretion of radiation by Brans-Dicke black holes overrides the effect of Hawking evaporation during the radiation dominated era. The subsequent evaporation of the black holes in later eras is further modified due to the variable gravitational ``constant,'' and they could survive up to longer times compared to the case of standard cosmology. We estimate the impact of accretion on modification of the constraint on their initial mass fraction obtained from the $\\ensuremath{\\gamma}$-ray background limit from presently evaporating primordial black holes.
B. NAYAK and L. P. SINGH
World Scientific Pub Co Pte Lt
The present-day accelerated expansion of the universe is naturally addressed within the Brans–Dicke theory just by using holographic dark energy model with inverse of Hubble scale as IR cutoff and power law temporal behavior of scale factor. It is also concluded that if the universe continues to expand, then one day it might be completely filled with dark energy.