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We demonstrate that the spinning LQG black hole can act as a cosmic particle accelerator. The LQG solution is singularity-free and can possess spin greater than that of a Kerr black hole. The additional black hole hair, arising from quantum effects, significantly influences the particle dynamics around the black hole. Under suitable physical conditions, the center-of-mass energy can grow arbitrarily high during the collision of two generic particles in the spacetime of an extremal black hole. In the non-extremal case, there exists a finite upper bound on the center-of-mass energy, the maximum value of which depends on the LQG parameter. These results are particularly interesting from an astrophysical perspective, especially in the context of probing Planck-scale physics., Comment: 19 pages, 6 figures

Employing the free energy landscape, we study the phase transition and its dynamics for a class of regular black holes in Anti-de Sitter spacetime governed by the coupling of non-linear electrodynamics, which reduces to Hayward and Bardeen solutions for particular values of spacetime parameters. The Fokker-Planck equation is solved numerically by imposing the reflecting boundary condition and a suitable initial condition, using which, we investigate the probabilistic evolution of regular AdS black holes. In this approach, the on-shell Gibbs free energy is treated as a function of the radius of the event horizon, which happens to be the order parameter of the phase transition. The numerical solution is also obtained for the absorbing boundary condition. The dynamics of switching between the coexistence small black hole phase and large black hole phase due to the thermal fluctuation is probed by calculating the first passage time. The effect of temperature on the dynamical process is also investigated., Comment: 20 pages, 10 figures. Comments are welcome

In this article, we study the propagation of scalar fields in the gravitational background of a spherically symmetric, electrically charged, regular-de Sitter black holes in higher dimensions. We carry out a thorough investigation of the grey body factors, by deriving analytical expressions for both minimally and non-minimally coupled scalar fields. Then we study the profile of grey body factors in terms of particle properties, namely the angular momentum quantum number and the non-minimal coupling constant, and the spacetime properties, namely the dimension, the cosmological constant and the non-linear charge parameter. We then derive the Hawking radiation spectra for a higher-dimensional electrically charged regular-de Sitter black hole. We find that the non-minimal coupling may suppress the greybody factor and the non-linear charge parameter may enhance it, but they both suppress the energy emission rate of Hawking radiation., Comment: 26 pages, 5 figures. Comments are welcome

We study the thermodynamics of Ayon Beato-Garcia black hole and the relation between the photon orbits and the thermodynamic phase transition of the black hole. Then we study the interaction between the microstructures of the black hole using Ruppeiner geometry. The radius of photon orbit and minimum impact parameter behave non-monotonously below the critical point, which mimics the behaviour of Hawking temperature and pressure in extended thermodynamics. Their change during the large black hole and small black hole phase transition serve as the order parameter, having a critical exponent $1/2$. The results show that gravity and thermodynamics of Ayon Beato-Garcia black hole are closely related. Following this we study the thermodynamic geometry which gives insight of the microstructure interaction of the black hole. We find that the large black hole phase is analogous to bosonic gas with a dominant attractive interaction, and the small black hole phase behaves like an anyonic gas with both attractive and repulsive interactions., Comment: 21 pages, 12 figures. Comments are welcome

A detailed discussion on phase transition and microscopic structure of charged AdS black hole with a global monopole is presented in both extended and alternate phase spaces. In the analysis of critical behaviour, the classical van der Waals analogy is drawn from isotherms which is followed by Gibbs free energy study and coexistence curves. In both spaces, the symmetry breaking parameter $\eta$ acts as a hindrance for critical behaviour. The crux of van der Waals like behaviour is investigated by looking at the microscopic structure of the black hole via thermodynamic Ruppeiner geometry. The Ruppeiner invariant scalar behaves differently in extended and alternate spaces. The monopole parameter influences the microscopic structure of the black hole, which in turn, affects the critical behaviour. The effect is significant at the maximal strength of the monopole parameter., Comment: 38 pages, 8 figures, comments are welcome!

We investigate thermodynamics and geometrothermodynamics of regular Bardeen AdS black hole with quintessence. The thermodynamics of the black hole is studied using temperature-entropy ($T-S$) , Pressure-Volume ($P-v$), and Gibbs energy plots, which indicate a critical behaviour.This is also confirmed from the divergence of specific heat against entropy, which shows a second-order phase transition. Moreover, we observe that the quintessence state parameter $\omega$ shifts the transition point to lower entropy values. Using the concept of thermodynamic Ruppeiner and Weinhold geometry, we calculated the thermodynamic curvature scalar $R_R$ and $R_W$ in the quintessence dark energy regime ($\omega =-2/3$). While these curvature scalars enable us to identify the critical behavior, they do not show divergence at the phase transition points observed in specific heat studies. To resolve this puzzle, we have adopted the method of geometrothermodynamics proposed by Hernando Quevedo. Choosing a Legendre invariant Quevedo metric, the curvature scalar $R_Q$ shows singularity at the same point as seen in the specific heat divergence., Comment: 20 pages,12 figures

In this paper, we investigate the Joule Thomson effects for AdS black holes with a global monopole. We study the effect of the global monopole parameter {\eta} on the inversion temperature and isenthalpic curves. The obtained result is compared with Joule Thomson expansion of van der Waals fluid and the equivalence were noted. Phase transition occuring in the extended phase space of this black hole is analogous to van der Waals gas. Our study shows that global monopole parameter {\eta} plays a very important role in Joule Thomson expansion., Comment: Contains 19 pages,19 figures

We study the noncommutative massless Kalb-Ramond gauge field coupled to a dynamical U(1) gauge field in the adjoint representation together with a compensating vector field. We derive the Seiberg-Witten map and obtain the corresponding mapped action to first order in $\theta$. The (emergent) gravity structure found in other situations is not present here. The off-shell dual scalar theory is derived and it does not coincide with the Seiberg-Witten mapped scalar theory. Dispersion relations are also discussed. The p-form generalization of the Seiberg-Witten map to order $\theta $ is also derived., Comment: 7 pages, typos corrected, a footnote removed and a sentence added in the text