International Journal of Modern Physics A

The study of de-Sitter Reissner–Nordstrøm black holes allows us to uncover a Weak Gravity Conjecture in de-Sitter space. It states that for a given mass $m$ there should be a state with a charge $q$ bigger than a minimal value $q_{\mathrm{\text{min}}}(m,l)$, depending on the mass and the de-Sitter radius $l$, in Planck units. This reproduces the well-known flat space–time result $q>m/\sqrt{2}$ in the large radius limit (large $l$). In the highly curved de-Sitter space, ($l$) $q_{\mathrm{\text{min}}}$ behaves as $\sqrt{ml}$. Finally, we discuss the case of backgrounds from gauged R-symmetry in $N=1$ supergravity. This paper is based on [I. Antoniadis and K. Benakli, Fortsch. Phys. 68, 2000054 (2020), arXiv:2006.12512 [hep-th]].

In this paper, we compute at one loop the two-point functions of massless scalars in the Neumann–Dirichlet open-string sector of the type IIB orientifold compactified on $T^2\times T^4/{\mathbb{Z}}_2$, when ${𝒩}=2$ supersymmetry is spontaneously broken. This is done by evaluating correlation functions of “boundary-changing vertex operators” which are analogous to correlators of twist fields for closed strings. We use our results to compute the mass developed at one loop by the moduli fields arising in the Neumann–Dirichlet sector.

Here, we develop an original approach to investigate the grand canonical partition function of the multicomponent mixtures of Boltzmann particles with hard-core interaction in finite and even small systems of the volumes above 20 fm³. The derived expressions of the induced surface tension equation of state (EoS) are analyzed in detail. It is shown that the metastable states, which can emerge in the finite systems with realistic interaction, appear at very high pressures at which the hadron resonance gas, most probably, is not applicable at all. It is shown how and under what conditions the obtained results for finite systems can be generalized to include into a formalism the equation for curvature tension. The applicability range of the obtained equations of induced surface and curvature tensions for finite systems is discussed and their close relations to the equations of the morphological thermodynamics are established. The hadron resonance gas model on the basis of the obtained advanced EoS is worked out. Also, this model is applied to analyze the chemical freeze-out of hadrons and light nuclei with the number of (anti-) baryons not exceeding 4. Their multiplicities were measured by the ALICE Collaboration in the central lead–lead collisions at the center-of-mass energy $\sqrt{s_{\mathrm{\text{NN}}}}=2.76$ TeV.

The Pierre Auger Observatory is the world’s largest detector of ultra-high energy cosmic rays (UHECRs). It uses an array of fluorescence telescopes and particle detectors at the ground to obtain detailed measurements of the energy spectrum, mass composition and arrival directions of primary cosmic rays (above the energy of $10^{17}$ eV) with accuracy not attainable until now.

Observations of extensive air showers performed by the Pierre Auger Observatory can also be used to probe hadronic interactions at high energy, in a kinematic and energy region not accessible by man-made accelerators. Indeed, exploiting Auger data, we reach center-of-mass energies up to 400 TeV, i.e. more than 30 times of those attainable at the Large Hadron Collider (LHC), and explore interactions in the very forward region of phase space on targets of atomic mass of 14. In addition, a precise measurement of the muon component of air showers at the ground is more sensitive to the details of the hadronic interactions along many steps of the cascade development, such as the multiplicity of the secondaries and the fraction of electromagnetic component with respect to the total signal. On the other hand, the intrinsic muon fluctuations mostly depend on the first interaction.

In this paper, we overview the new Auger studies exploring the connection between the dynamics of the air shower and the multi-particle production, and how this knowledge can be translated into constraints of the high-energy hadronic models as well as direct measurements, complementary to, and beyond the reach of, accelerator experiments.

In this paper, we develop a thermal description for photon modes within the context of bouncing universe. Within this study, we start with a Lorentz-breaking dispersion relation which accounts for modified Friedmann equations with a bounce solution. We calculate the spectral radiance, the entropy, the Helmholtz free energy, the heat capacity and the mean energy. Nevertheless, the latter two ones turn out to contribute only in a trivial manner. Furthermore, one intriguing aspect gives rise to: for some configurations of $\eta$, $l_P$ and $T$, the thermodynamical behavior of the system seems to indicate instability. However, despite showing this particularity, the solutions of the thermodynamic functions in general turn out to agree with the literature, e.g. the second law of thermodynamics is maintained. More so, all the results are derived analytically and three different regimes of temperature of the universe are also considered, i.e. the inflationary era, the electroweak epoch and the cosmic microwave background.

In this paper, we compute explicitly the Khovanov polynomials (using the computer program from katlas.org) for the two simplest families of the satellite knots, which are the twisted Whitehead doubles and the two-strand cables. We find that a quantum group decomposition for the HOMFLY polynomial of a satellite knot can be extended to the Khovanov polynomial, whose quantum group properties are not manifest. Namely, the Khovanov polynomial of a twisted Whitehead double or two-strand cable (the two simplest satellite families) can be presented as a naively deformed linear combination of the pattern and companion invariants. For a given companion, the satellite polynomial “smoothly” depends on the pattern but for the “jump” at one critical point defined by the $s$-invariant of the companion knot. A similar phenomenon is known for the knot Floer homology and $\tau$-invariant for the same kind of satellites.

In this paper, we investigate the relativistic dynamics of a fermion–antifermion pair holding through Dirac oscillator interaction in the rotating frame of $(2+1)$-dimensional topological defect-generated geometric background. We obtain an exact energy spectrum for the system in question by solving the corresponding form of a fully covariant two-body Dirac equation. This energy spectrum depends on the angular velocity $(\mathrm{\Omega })$ of uniformly rotating frame and angular deficit $(\propto \alpha )$ in the geometric background. Our results show that the effects of $\alpha$ on each energy level of the system are not same and the $\mathrm{\Omega }$ impacts on the strength of interaction between the particles. Furthermore, we observe that it seems to be possible to actively tune the dynamics of such a fermion–antifermion system, in principle.