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Dhwani Gangal

Publications and source records attributed to Dhwani Gangal.

5 recordsLinked to original sources

Black Hole Evaporation Driven by Non-Thermal Squeezing Through SNS and CSNS Dynamics

In this work, we present a comprehensive semiclassical analysis of black hole radiation in a spatially flat FRW Universe for two fundamental nonclassical states: the Squeezed Number State (SNS) and the Coherent Squeezed Number State (CSNS). Unlike thermally modified earlier studies, SNS and CSNS constitute fully non-thermal, number-state-dependent quantum configurations. By embedding these states within the framework of semiclassical theory of gravity, we derive state-resolved expressions for the Hawking temperature, entropy variation, and corresponding mass loss of an evaporating black hole. The influence of the squeezing parameter $ρ$ and number state parameter $n$ on Hawking emission is examined through a series of analytical results supported by twelve detailed plots. The analysis reveals that the Hawking temperature exhibits monotonic growth with increasing $ρ$ and $n$, thereby elevating the effective temperature experienced at the black hole horizon. The entropy variations $Δ\mathbb{S}_{\mathrm{SNS}}$ and $Δ\mathbb{S}_{\mathrm{CSNS}}$ show strong nonlinear enhancement, especially at moderate and large squeezing values. Overall, the study extends earlier thermal squeezed-state approaches to a fully number-state-resolved framework, highlighting the sensitivity of Hawking emission to nonclassical quantum configurations. These findings contribute a new perspective on gravitational particle creation in cosmological settings.

gr-qc

Investigation of Super-Poissonian Nonclassical Nature of Inflaton Field in Flat FRW Universe through Cosmological Mandels $Q$ Parameter

This study investigates the nonclassical properties of the inflaton field within the framework of semiclassical gravity by analyzing Cosmological Mandels $Q$ parameter for Squeezed Number States (SNS) and Coherent Squeezed Number States (CSNS). Mandels $Q$ parameter serves as a critical tool for identifying nonclassical states by differentiating between sub-Poissonian and super-Poissonian statistics. The values of Cosmological Mandels $Q$ are positive shows the super-Poissonian non-classical nature of inflaton for Squeezed Number States (SNS) and Coherent Squeezed Number States (CSNS). These results provide deeper insights into the statistical properties of quantum states in early-universe cosmology and emphasize the relevance of SNS and CSNS in understanding quantum effects on cosmic inflation and particle production.

gr-qc

Particle Production and Density Fluctuations of Non-classical Inflaton in Coherent Squeezed Vacuum State of Flat FRW Universe

We study non-classical inflaton, which is minimally coupled to the semiclassical gravity in FRW universe in Coherent Squeezed Vacuum State (CSVS). We determined Oscillatory phase of inflaton, power-law expansion, scale factor, density fluctuations, quantum fluctuations and particle production for CSVS. We obtained an estimated leading solution of scale factor in CSVS proportional to $t^{2/3}$ follow similar diversification as demonstrated by Semiclassical Einstein Equation (SCEE) of gravity in matter dominated universe. We also studied the validity of SCEE in CSVS. By determining the quantum fluctuation for CSVS validity of uncertainty relation for FRW Universe also computed. The results shows that Quantum fluctuations doesn't depend on coherent parameter $Υ$ as uncertainty relation doesn't effected by the displacement of $Υ$ in phase space. We study the production of particles in CSVS for oscillating massive inflaton in flat FRW universe.

astro-ph.CO

Density fluctuations for Squeezed Number State and Coherent Squeezed Number State in Flat FRW Universe

We study the density fluctuations for Coherent Squeezed Number State (CSNS) and Squeezed Number States (SNS) formalism in Semiclassical theory of grav ity in flat FRW universe. We used Number state evolution of oscillatory phase of inflaton for coherent squeezed number state and squeezed number states for malisms. We analyzed that density fluctuations for SNS depends upon squeezing parameter and number state while for CSNS density fluctuations depends upon squeezing parameter, number state and coherent state parameter. These param eters plays an important role for quantum consideration of SNS and CSNS. The results of the analysis shows that increase in density fluctuations for both SNS and CSNS, demonstrate quantum behavior of SCEE as well as production of various kind of particles in these states.

gr-qc

Reheating constraints on mutated hilltop inflation

Future research studies of cosmic microwave background polarization seems likely to provide a more improved upper bound of $r \le 0.03$ on the tensor-to-scalar ratio(r). In our work, we have done the reheating study of mutated hilltop inflation(MHI), a model falling in the broad category of small field inflation. We have parameterized reheating in terms of various parameters like reheating duration $N_{\text{rh}}$, reheating temperature $T_{\text{rh}}$ and effective equation of state $\overline{ω}_{\text{rh}}$ using observationally viable values of scalar power spectrum amplitude $A_{\text{s}}$ and scalar spectral index $n_{\text{s}}$. In our study, working over a range of $\overline{ω}_{\text{rh}}$, we found that the MHI potential is well consistent with combined Planck and BK18 observations for $\overline{ω}_{\text{rh}} > 0$ within a particular range of model's parameter space and the lower values of the model parameter in MHI generate considerably smaller r compared to normal hilltop potential without any incompatibility of $n_s$ with observational data, making MHI a better choice in accordance to recent and future studies.

astro-ph.CO