In this paper, we investigate the effect of the Generalized Uncertainty Principle (GUP) in the Casimir wormhole spacetime recently proposed by Garattini (Eur Phys J C 79: 951, 2019). In particular, we consider three types of GUP relations, firstly the Kempf, Mangano and Mann (KMM) model, secondly the Detournay, Gabriel and Spindel (DGS) model, and finally the so-called type II model for the GUP principle. To this end, we consider three specific models of the redshift function along with two different equations of state (EoS), given by $${\mathcal {P}}_r(r)=\omega _r(r) \rho (r)$$Pr(r)=ωr(r)ρ(r) and $${\mathcal {P}}_t(r)=\omega _t (r){\mathcal {P}}_r(r)$$Pt(r)=ωt(r)Pr(r) and obtain a class of asymptotically flat wormhole solutions supported by Casimir energy under the effect of GUP. Furthermore we check the null, weak, and strong condition at the wormhole throat with a radius $$r_0$$r0 , and we show that in general the classical energy conditions are violated by some arbitrary quantity at the wormhole throat. Importantly, we examine the wormhole geometry with semiclassical corrections via embedding diagrams. We also consider the ADM mass of the wormhole, the volume-integral quantifier to calculate the amount of the exotic matter near the wormhole throat, and the deflection angle of light.

We explore the paradigm in which inflation is driven by a four-dimensional strongly coupled dynamic with a nonminimal coupling to gravity. We introduce a model where the inflaton is identified with the glueball field of a pure Yang-Mills theory. We introduce the dilatonic-like glueball action, which is obtained by requiring saturation of the underlying Yang-Mills trace anomaly at the effective action level. We couple the resulting action nonminimally to gravity. We demonstrate that it is possible to achieve successful inflation with the confining scale of the underlying Yang-Mills theory naturally of the order of the grand unified energy scale. We also argue that the metric formulation gives a more consistent picture for models of composite inflation than the Palatini one. Finally, we show that, within the metric formulation, the model nicely respects tree-level unitarity for the scattering of the inflaton field all the way to the Planck scale.

We investigate models in which the inflaton emerges as a composite field of a four dimensional, strongly interacting and nonsupersymmetric gauge theory featuring purely fermionic matter. We show that it is possible to obtain successful inflation via non-minimal coupling to gravity, and that the underlying dynamics is preferred to be near conformal. We discover that the compositeness scale of inflation is of the order of the grand unified energy scale.

The detection of gravitational waves (GWs) from a binary neutron star (BNS) has opened a new window on gravitational wave astronomy. With current sensitivities, detectable signals coming from compact objects like neutron stars turn out to be a crucial ingredient for probing their structure, composition, and evolution. Moreover, astronomical observations on pulsars and their mass–radius relations place important constraints on the dense matter equation of state. In this paper, we consider a homogeneous and unpaired charge-neutral three-flavor interacting quark matter with corrections that account for the moderately heavy strange quark instead of the naive MIT bag model. We perform a detailed analysis of strange quark stars in the context of the recently proposed 4D Einstein–Gauss–Bonnet (EGB) theory of gravity. However, this theory does not have standard 4D equations. Thus, we show that the equivalence of the actions in the regularized 4D EGB theory and in the original one is satisfied for a spherically symmetric spacetime. We pay particular attention to the possible existence of neutron stars of mass compatible with . Our findings suggest that the fourth-order correction parameter (a ₄) of the quantum chromodynamic perturbation and coupling constant α of the GB term play an important role in the mass–radius relation as well as the stability of the quark star. Finally, we compare the results with the well-measured limits of pulsars and their mass and radius extracted from the spectra of several X-ray compact sources.

The existence of strange matter in compact stars may give rise to striking outcomes of the various physical phenomena. As an alternative to neutron stars, a new class of compact stars called strange stars should exist if the strange matter hypothesis is true. In this paper, we investigate the possible construction of strange stars in quark matter phases based on the MIT bag model. We consider scenarios in which strange stars have no crusts. Then we apply two types of equations of state to quantify the mass–radius diagram for static strange star models, performing the numerical calculation of the modified Tolman–Oppenheimer–Volkoff equations in the context of 4D Einstein–Gauss–Bonnet (EGB) gravity. It is worth noting that the GB term gives rise to a nontrivial contribution to the gravitational dynamics in the limit D → 4. However, the claim that the resulting theory is one of pure gravity has been cast in doubt on several grounds. Thus, we begin our discussion by showing the regularized 4D EGB theory has an equivalent action as the novel 4D EGB in a spherically symmetric spacetime. We also study the effects of coupling constant α on the physical properties of the constructed strange stars including the compactness and criterion of adiabatic stability. Finally, we compare our results to those obtained from standard general relativity.

Recent investigations have shown that inflation can be driven by four-dimensional strongly interacting theories nonminimally coupled to gravity. We explore this paradigm further by considering composite inflation driven by orientifold field theories. The advantage of using these theories resides in the fact that at large number of colors they feature certain super Yang-Mills properties. In particular, we can use for inflation the bosonic part of the Veneziano-Yankielowicz effective theory. Furthermore, we include the 1/N as well as fermion mass corrections at the effective Lagrangian level allowing us to explore the effects of these corrections on the inflationary slow-roll parameters. Additionally, the orientifold field theory with fermionic matter transforming according to the two-index antisymmetric representation for three colors is QCD. Therefore, this model can be interpreted as a new nonminimally coupled QCD theory of inflation. The scale of composite inflation, for all the models presented here, is of the order of 1016\,\,GeV. Unitarity studies of the inflaton scattering suggest that the cutoff of the model is at the Planck scale.