<p>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.</p>

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.

India

Kshitish Pradhan

Bhagyarathi Sahoo

Dushmanta Sahu

Raghunath 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

Two particles can exert forces on each other when embedded in a sea of weakly coupled particles. These “wake forces” occur whenever the source and target particles have quadratic interactions with the mediating particles; they are proportional to the ambient energy density and typically have a range of order the characteristic de Broglie wavelength of the background. The effect can be understood as source particles causing a disturbance in the background waves—a wake—which subsequently interacts with the target particles. Wake forces can be mediated by bosons or fermions, can have spin dependence, may be attractive or repulsive, and have a generally anisotropic spatial profile and range that depends on the phase-space distribution of the ambient particles. In this work, I investigate the application of wake forces to dark matter searches, recast existing limits on short-range forces into leading constraints on dark matter with quadratic couplings, and sketch out potential experimental modifications to optimize sensitivity. Wake forces occur in the Standard Model: the presence of the cosmic neutrino background induces a millimeter-range force about 22 orders of magnitude weaker than gravity. Wake forces may also be relevant in condensed-matter and atomic physics.

United States

Ken Van Tilburg

Wake forces in a background of quadratically coupled mediators

Axion dark matter (DM) constitutes an oscillating background that violates parity and time-reversal symmtries. Inside piezoelectric crystals, where parity is broken spontaneously, this axion background can result in a stress. We call this new phenomenon “the piezoaxionic effect.” When the frequency of axion DM matches the natural frequency of a bulk acoustic normal mode of the piezoelectric crystal, the piezoaxionic effect is resonantly enhanced and can be read out electrically via the piezoelectric effect. We explore all axion couplings that can give rise to the piezoaxionic effect—the most promising one is the defining coupling of the QCD axion, through the anomaly of the strong sector. We also point our another, subdominant phenomenon present in all dielectrics, namely the “electroaxionic effect.” An axion background can produce an electric displacement field in a crystal which in turn will give rise to a voltage across the crystal. The electroaxionic effect is again largest for the axion coupling to gluons. We find that this model-independent coupling of the QCD axion may be probed through the combination of the piezoaxionic and electroaxionic effects in piezoelectric crystals with aligned nuclear spins, with near-future experimental setups applicable for axion masses between <math><msup><mn>10</mn><mrow><mo>−</mo><mn>11</mn></mrow></msup><mtext> </mtext><mtext> </mtext><mi>eV</mi></math> and <math><msup><mn>10</mn><mrow><mo>−</mo><mn>7</mn></mrow></msup><mtext> </mtext><mtext> </mtext><mi>eV</mi></math>, a challenging range for most other detection concepts.

Canada

Asimina Arvanitaki

Amalia Madden

Piezoaxionic effect

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.

Kshitish Kumar Pradhan

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.