Searcharxiv⌕ Search

arXiv subjects

Bikram Ghosh

Publications and source records attributed to Bikram Ghosh.

8 recordsLinked to original sources
arXiv2025

Investigating Evolving Wormholes in $f(R,T)$ Gravity

The present work examines whether evolving wormhole solution is possible or not in $f(R,T)$ modified gravity theory. In the background of inhomogeneous FLRW type wormhole configuration the field equations are investigated for different choices of scale factors and shape functions. For the power law and exponential choice of the scale factor from cosmological context and decoupled power law of $f(R,T)$ in each variable, wormhole configuration has been examined for two viable choices of shape function. Energy conditions are examined graphically for a range of values of the parameters involved. Finally, the possibility of emergent scenario at early cosmic evolution has been examined.

gr-qc↗
arXiv2024

LabSafety Bench: Benchmarking LLMs on Safety Issues in Scientific Labs

Artificial Intelligence (AI) is revolutionizing scientific research, yet its growing integration into laboratory environments presents critical safety challenges. Large language models (LLMs) and vision language models (VLMs) now assist in experiment design and procedural guidance, yet their "illusion of understanding" may lead researchers to overtrust unsafe outputs. Here we show that current models remain far from meeting the reliability needed for safe laboratory operation. We introduce LabSafety Bench, a comprehensive benchmark that evaluates models on hazard identification, risk assessment, and consequence prediction across 765 multiple-choice questions and 404 realistic lab scenarios, encompassing 3,128 open-ended tasks. Evaluations on 19 advanced LLMs and VLMs show that no model evaluated on hazard identification surpasses 70% accuracy. While proprietary models perform well on structured assessments, they do not show a clear advantage in open-ended reasoning. These results underscore the urgent need for specialized safety evaluation frameworks before deploying AI systems in real laboratory settings.

cs.CL↗
arXiv2024

Does Dynamical Wormhole Evolve From Emergent Scenario?

In the present work we analyse a dynamical wormhole solution with two fluids system (one isotropic and homogeneous and the other being inhomogeneous and anisotropic in nature) as the matter at the throat. We choose two different forms of Equation of State(EoS) and investigate two solutions of the wormhole geometry. The properties to ensure existence and traversability has been analysed. Also, the model of the dynamic wormhole has been examined for a possibility of the Emergent Universe(EU) model in cosmological context. Finally, for the dynamical wormholes so obtained, Null Energy Condition(NEC) has been examined near the throat.

gr-qc↗
arXiv2023

Wormhole generating function in $f(R,T)$ gravity

In this present work, we have studied the traversable wormhole geometries in $f(R,T)$ gravity theory, where $R$ denotes the Ricci scalar and $T$ is the trace of the energy-momentum tensor. Firstly, two new shape functions are obtained for some assumed generating function. Also, some new generating functions are obtained in wormhole geometry for some well known shape functions and redshift functions. Energy conditions are examined in each wormhole solution and it is found that a particular type of wormhole satisfies all the energy conditions in a region.

gr-qc↗
arXiv2021

A new shape function and some specific wormhole solutions in braneworld scenario

Considering a energy density of the form $ρ=q\left({\frac{r}{r_0}}\right)^{-n}$( where $q$ is an arbitrary positive constant with dimension of energy density and $n>0$), a shape function is obtained by using field equations of braneworld gravity theory in this paper. Under isotropic scenario wormhole solutions are obtained considering six different redshift functions along with the obtained new shape function. For anisotropic case wormhole solutions are obtained under the consideration of five different shape functions along with the redshift function $ϕ=βln(\frac{r}{r_0})$, where $β$ is an arbitrary constant. In each case all the energy conditions are examined and it is found that for some cases all energy conditions are satisfied in the vicinity of the wormhole throat and for the rest cases all energy conditions are satisfied except strong energy condition.

gr-qc↗
arXiv2021

Wormhole solutions in $f(R)$ gravity theory for Chaplygin gas scenario

The present paper deals with some wormhole solutions which are obtained by taking two different shape functions along with zero tidal force. For obtaining wormhole solutions, anisotropic fluid and a equation of state $p_t=-\frac{a}ρ$ related by Chaplygin gas are considered where $ρ$ is the energy density, $p_t$ is tangential pressure and $a$ is positive constant. Energy conditions are examined for two different models, and it is found that a major energy conditions are satisfied in a region.

gr-qc↗
arXiv2021

Some specific wormhole solutions in $f(R)$-modified gravity theory

The paper deals with the static spherically symmetric wormhole solutions in $f(R)$-modified gravity theory with anisotropic matter field and for some particular choices for the shape functions. The present work may be considered as an extension of the general formalism in \cite{r15} for finding wormhole solutions. For isotropic matter distribution it has been shown that wormhole solutions are possible for zero tidal force and it modifies the claim in \cite{r17}. Finally energy conditions are examined and it is found that all energy conditions are satisfied in a particular domain with a particular choice of the shape function.

gr-qc↗