We construct a large number of exact solutions of three-dimensional gravity with heavy matter particles that generalize the construction of Antonini, Sasieta, and Swingle, argued to define CFT states dual to a spacetime with a closed baby-universe cosmology. Our construction starts with an arbitrary heavy-particle closed universe cosmology of the type constructed in Maloney, Meruliya, and Van Raamsdonk [<a href="http://arXiv.org/abs/2503.12227">arXiv:2503.12227</a>] and via a gluing procedure adds an arbitrary number of AdS tubes connecting the past and future conformal boundaries of the associated Euclidean wormhole solution. With our construction, it is straightforward to produce examples where the cosmology is approximately homogeneous and isotropic. We describe a necessary condition for the cosmological wormhole saddle to dominate the Euclidean path integral with the specified boundary conditions. We argue that the original Antonini-Sasieta-Swingle construction usually does not meet this condition and describe alternative saddles that are likely to dominate. We discuss various possibilities for how the cosmological saddle might be made to dominate in our generalized construction.

Canada

Mark Van Raamsdonk

Alejandro Vilar López

Menagerie of Euclidean constructions for 3D holographic cosmologies

We investigate the general susceptibilities in the charm sector by using the van der Waals hadron resonance gas model (VDWHRG).We argue that the ideal hadron resonance gas, which assumes no interactions between hadrons, and the excluded volume hadron resonance gas, which includes only repulsive interactions, fail to explain the lattice quantum chromodynamics (lQCD) data at very high temperatures. In contrast, the VDWHRG model, incorporating both attractive and repulsive interactions, extends the degree of agreement with lQCD up to nearly 180 MeV. We estimate the partial pressure in the charm sector and study charm susceptibility ratios in a baryon-rich environment, which is tricky for lQCD due to the fermion sign problem. Our study further solidifies the notion that the hadrons should not be treated as noninteracting particles, especially when studying higher order fluctuations, but rather one should consider both attractive and repulsive interactions between the hadrons.

India

Kangkan Goswami

Kshitish Kumar Pradhan

Mexico

Dushmanta Sahu

Raghunath Sahoo

Partial pressure and susceptibilities of the charmed sector in the van der Waals hadron resonance gas model

We formulate fermionic versions, for any number of spatial dimensions, of the van der Waals and Casimir-Polder interactions and study their properties. In both cases, the systems we introduce contain localized “atoms”: two-level systems, coupled to a vacuum Dirac field. This Dirac field plays here a role akin to the electromagnetic field in the van der Waals case. In this context, bag model conditions for the Dirac field serve as the analog of the “mirror” in the Casimir-Polder effect. We found that, in this case, the resulting interaction is repulsive.

Argentina

C.D. Fosco

G. Hansen

Fermionic van der Waals and Casimir-Polder interactions

This paper is designed for heavy pulsars coming from the Neutron Star Interior Composition Explorer. The research model is describe by Einstein field equations for anisotropic fluid configuration with spherical symmetry. As per present perceptiveness, modified non-linear Van der Waals equation of state is used to relate physical variables. The continuity of inner and outer matter is obtained by comparing inner spacetime to outer Schwarzschild metric. The physical viability of this model is evaluated and further it is compared with observational data of pulsars PSR J0348+0432, PSR J0740+6620 and PSR J0030+0451. The model fulfils all physical and mathematical characteristics of the dense structure studies. It offers the factual proofs carried by evolution of celestial configurations. The working model presented here is physically viable and shows stable behaviour.

Pakistan

S. Mardan

A. Khalid

Rubab Manzoor

Lebanon

Czechia

Muhammad Riaz

Anisotropic model observing pulsars from Neutron Star Interior Composition with modified Van der Waals equation of state

Studying the thermodynamics of the systems produced in ultra-relativistic heavy-ion collisions is crucial in understanding the QCD phase diagram. Recently, a new avenue has opened regarding the implications of large initial angular momentum and subsequent vorticity in the medium evolution in high-energy collisions. This adds a new type of chemical potential into the partonic and hadronic systems, called the rotational chemical potential. We study the thermodynamics of an interacting hadronic matter under rotation, formed in an ultra-relativistic collision. We introduce attractive and repulsive interactions through the van der Waals equation of state. Thermodynamic properties like the pressure (P), energy density ( $$\varepsilon $$ <math> <mi>ε</mi> </math> ), entropy density (s), trace anomaly ( $$(\varepsilon - 3P)/T^{4}$$ <math> <mrow> <mrow> <mo>(</mo> <mi>ε</mi> <mo>-</mo> <mn>3</mn> <mi>P</mi> <mo>)</mo> </mrow> <mo>/</mo> <msup> <mi>T</mi> <mn>4</mn> </msup> </mrow> </math> ), specific heat ( $$c_\textrm{v}$$ <math> <msub> <mi>c</mi> <mtext>v</mtext> </msub> </math> ) and squared speed of sound ( $$c_\textrm{s}^{2}$$ <math> <msubsup> <mi>c</mi> <mtext>s</mtext> <mn>2</mn> </msubsup> </math> ) are studied as functions of temperature (T) for zero and finite rotation chemical potential. The conserved charge fluctuations, which can be quantified by their respective susceptibilities, are also studied. The rotational (spin) density corresponding to the rotational chemical potential is explored. In addition, we explore the possible liquid–gas phase transition in the hadron gas with van der Waals interaction in the T – $$\omega $$ <math> <mi>ω</mi> </math> phase space.

Kshitish Pradhan

Bhagyarathi Sahoo

Thermodynamics of a rotating hadron resonance gas with van der Waals interaction

In this paper, the m-component super KP hierarchy in form of free superfermions is constructed by Clifford superalgebra. The super bosonic counterpart of this hierarchy is described by using the vertex operators. Based on this, some super Hirota equations are determined and the bilinear identity is expressed by super Baker functions and tau function. Darboux transformation in terms of superfermions is also discussed.

China

Huizhan Chen

The m-component super KP hierarchy in Kac-van de Leur version

Abstract In this work, we study the thermodynamic topology of a static, a charged static, and a charged rotating black hole in f(R) gravity. For charged static black holes, we work in two different ensembles: the fixed charge (q) ensemble and fixed potential (ϕ) ensemble. For charged rotating black holes, four different types of ensembles are considered: fixed (q, J), fixed (ϕ, J), fixed (q, Ω), and fixed (ϕ, Ω) ensemble, where J and Ω denote the angular momentum and the angular frequency, respectively. Using the generalized off-shell free energy method, where the black holes are treated as topological defects in their thermodynamic spaces, we investigate the local and global topologies of these black holes via the computation of winding numbers at these defects. For the static black hole we work in three models. We find that the topological charge for a static black hole is always −1 regardless of the values of the thermodynamic parameters and the choice of f(R) model. For a charged static black hole, in the fixed charge ensemble, the topological charge is found to be zero. Contrastingly, in the fixed ϕ ensemble, the topological charge is found to be −1. For charged static black holes, in both the ensembles, the topological charge is observed to be independent of the thermodynamic parameters. For charged rotating black holes, in the fixed (q, J) ensemble, the topological charge is found to be 1. In the fixed (ϕ, J) ensemble, we find the topological charge to be 1. In the case of the fixed (q, Ω) ensemble, the topological charge is 1 or 0 depending on the value of the scalar curvature (R). In the fixed (Ω, ϕ) ensemble, the topological charge is −1, 0, or 1 depending on the values of R, Ω, and ϕ. Therefore, we conclude that the thermodynamic topologies of the charged static black hole and charged rotating black hole are influenced by the choice of ensemble. In addition, the thermodynamic topology of the charged rotating black hole also depends on the thermodynamic parameters.

Bidyut Hazarika

Prabwal Phukon

Thermodynamic Topology of Black Holes in f(R) Gravity Nobel Lecture: Accelerating Expansion of the Universe through Observation of Distant Supernovae RPS thermodynamics of Taub–NUT AdS black holes in the presence of central charge and the weak gravity conjecture Topological Interpretation of Black Hole Phase Transition in Gauss-Bonnet Gravity Thermodynamic Topological Classifications of Well-Known Black Holes Topology of black hole thermodynamics via Rényi statistics Rényi Topology of Charged-flat Black Hole: Hawking-Page and Van-der-Waals Phase Transitions Topology and phase transition for EPYM AdS black hole in thermal potential Thermodynamic phase transition and winding number for the third-order Lovelock black hole Topology of critical points in boundary matrix duals Topological classes of BTZ black holes Thermodynamic Topology of D=4,5 Horava Lifshitz Black Hole in Two Ensembles Thermodynamic topology of Kerr-Sen black holes via Rényi statistics The structure of the topological current Propagation and Fluxes of Ultra High Energy Cosmic Rays in f(R) Gravity Theory Anisotropies of Diffusive Ultra-high Energy Cosmic Rays in f(R) Gravity Theory

Luminosity is the key quantity characterizing the performance of charged particle colliders. Precise luminosity determination is an important task in collider physics. Part of this task is the proper calibration of detectors dedicated for luminosity measurements. The wide-used experimental method of calibration is the van-der-Meer scan, which is the beam separation scan performed at specifically optimized beam conditions. This work is devoted to modeling this scan with the q-Gaussian distribution of particles in colliding beams. Because of its properties, the q-Gaussian distribution is believed to describe the density closer to reality than regular Gaussian-based models. In this work, the q-Gaussian model is applied for van-der-Meer scan modeling, and the benefits of this model for luminosity calibration task are demonstrated.

Egypt

Russia

Mohamed Abed

Anton Babaev

Leonid Sukhikh

Luminosity calibration by means of van-der-Meer scan for Q-Gaussian beams

We study the behavior of a hadronic matter in the presence of an external magnetic field within the van der Waals hadron resonance gas model, considering both attractive and repulsive interactions among the hadrons. Various thermodynamic quantities like pressure (<math><mi>P</mi></math>), energy density (<math><mi>ϵ</mi></math>), magnetization (<math><mi>M</mi></math>), entropy density (<math><mi>s</mi></math>), squared speed of sound (<math><msubsup><mi>c</mi><mi>s</mi><mn>2</mn></msubsup></math>), and specific-heat capacity at constant volume (<math><msub><mi>c</mi><mi>v</mi></msub></math>) are calculated as functions of temperature (<math><mi>T</mi></math>) and static finite magnetic field (<math><mi>e</mi><mi>B</mi></math>). We also consider the effect of baryochemical potential (<math><msub><mi>μ</mi><mi>B</mi></msub></math>) on the above-mentioned thermodynamic observables in the presence of a magnetic field. Further, we estimate the magnetic susceptibility (<math><msubsup><mi>χ</mi><mi>M</mi><mn>2</mn></msubsup></math>), relative permeability (<math><msub><mi>μ</mi><mi>r</mi></msub></math>), and electrical susceptibility (<math><msubsup><mi>χ</mi><mi>Q</mi><mn>2</mn></msubsup></math>) which can help us to understand the system better. Through this model, we quantify a liquid-gas phase transition in the <math><mrow><mi>T</mi><mo>−</mo><mi>e</mi><mi>B</mi><mo>−</mo><msub><mrow><mi>μ</mi></mrow><mrow><mi>B</mi></mrow></msub></mrow></math> phase space.

Effect of a magnetic field on the thermodynamic properties of a high-temperature hadron resonance gas with van der Waals interactions

In this manuscript, we analyze the thermodynamic properties of the Van der Waals black hole. For this purpose, we calculate the geometric mass, Hawking temperature, thermodynamic mass, heat capacity, and Gibbs free energy. By studying the properties of mass and temperature, we depict the physical existence of Van der Waals black hole solutions. We calculate the mass of the black hole by using the first law of thermodynamics, then calculate the heat capacity and Gibbs free energy to discuss the phase transition of the Van der Waals black hole. We observe that both the Van der Waals parameters a and b have a significant effect on the thermodynamic properties of the black hole. Additionally, we compute the energy emission rate and show that the emission rate is directly proportional to the Van der Waals parameter. Furthermore, we investigate the effect of quantum gravity on the Van der Waals black hole produced by first-order gravity and also employ the Lagrangian equation, which has been modified by the generalized uncertainty principle (GUP). The tunneling radiation of a Van der Waals black hole is calculated after solving the field equations.