[en] We investigate the non-minimally Higgs inflaton (HI) model in the context of warm inflation scenario. Warm little inflaton (WLI) model considers the little Higgs boson as inflaton. The concerns of warm inflation model can be eliminated in WLI model. There is a special case of dissipation parameter in WLI model Γ = Γ₀T. Using this parameter, we study the potential of HI in Einstein frame. Finally we will constrain the parameters of our model using current Planck observational data. (orig.)

[en] We extend the recent proposal of twofold hidden conformal symmetry to the four-dimensional Kerr-Bolt-AdS-dS black holes. The J-picture of holographic description of Kerr-Bolt-AdS-dS black holes previously has been studied in the paper. Here we present a new description, in view of the NUT charge of black hole. We consider the wave equation of a massless charged scalar field in our interesting background and show in the near horizon region, the wave equation can be reproduced by the SL(2,R)_L x SL(2,R)_R Casimir quadratic operators. Moreover, we compute the microscopic entropy of the dual CFT by Cardy formula and find a perfect match to Bekenstein-Hawking entropy of Kerr-Bolt-AdS-dS spacetimes. The absorption cross section of a near region scalar field also matches to microscopic absorption cross section of the dual CFT. (author)

[en] According to a Barrow solution for the scale factor of the universe, the main properties of the tachyon inflation model in the framework of the RSII braneworld are studied. Within this framework the basic slow-roll parameters are calculated analytically. We compare this inflationary scenario to the latest observational data. The predicted spectral index and the tensor-to-scalar fluctuation ratio are in excellent agreement with those of Planck 2015. The current predictions are consistent with those of viable inflationary models. (orig.)

[en] High dissipative regime of warm pseudoscalar inflation model (Kamali in Phys Rev D 100:043520, arXiv:1901.01897 [gr-qc], 2019) with an approximately constant value of dissipation parameter Q is studied. Intermediate solution of the scale-factor related to the accelerated expansion of the Universe which is rolled out by observational data in the context of standard (cold) model of inflation is used. There is a region of free parameters phase-space of the model which is interestingly compatible with recent observational data. It is discussed that the model is also compatible with the swampland criteria in a broad range of parameters phase-space and TCC in a limited area of parameters.

[en] We show that extremal BMPV black holes have a hidden conformal symmetry. In this regard, we consider the wave equation of a massless scalar field propagating in extremal BMPV spacetime and find in the 'near region', the wave equation in extremal limit could be written in terms of the SL(2,R) quadratic Casimir. From the new conformal coordinates, the temperatures of the dual CFTs could be read directly. For the extremal black hole, the Hawking temperature is vanishing. Correspondingly, only the left (right) temperature of the dual CFT is non-vanishing and the excitations of the other sector are suppressed. Moreover, we obtain the microscopic entropy of the extremal BMPV black hole and find that the correlation function of a near-region scalar field matches to the microscopic greybody factor of the dual 2D CFT. (author)

[en] We study the main properties of the warm tachyon inflation model in the framework of the RSII braneworld based on Barrow's solution for the scale factor of the universe. Within this framework we calculate analytically the basic slow-roll parameters for different versions of warm inflation. We test the performance of this inflationary scenario against the latest observational data and we verify that the predicted spectral index and the tensor-to-scalar fluctuation ratio are in excellent agreement with those of Planck 2015. Finally, we find that the current predictions are consistent with those of viable inflationary models. (orig.)

[en] We demonstrate that the strict upper bounds on the energy scale of inflation and on the tensor-to-scalar ratio can be somewhat relaxed if we assume that - after an initial period of slow rolling when scales probed today in CMB experiments exit the Hubble radius - the equation of state of the background changes to correspond to an almost marginally accelerating universe. Constructing an actual model in which this happens appears, however, to be unnatural.

[en] In the context of Effective Field Theory, the Hilbert space of states increases in an expanding universe. Hence, the time evolution cannot be unitary. The formation of structure is usually studied using effective field theory techniques. We study the constraints on effective field theory analyses of early universe models which come from demanding that the factor of the space of states corresponding to length scales where the primordial fluctuations are manifest does not suffer from the unitarity problem. For bouncing and emergent cosmologies, no constraints arise provided that the energy scale of the bounce or emergent phases is smaller than the ultraviolet (UV) cutoff scale. On the other hand, in the case of the inflationary scenario, non-trivial upper bounds on the energy scale of inflation arise.

[en] Constant-roll warm inflation is introduced in this work. A novel approach to finding an exact solution for Friedman equations in the constant-roll framework is presented for cold inflation and is extended to warm inflation with the constant dissipative parameter Q=Γ/3H. The evolution of the primordial inhomogeneities of a scalar field in a thermal bath is also studied. The $1\mathrm{\sigma <!--\; ??\; -->}$ consistency between the theoretical predictions of the model and observational constraints has been proven for a range of $Q$ and β=−φ̈/(3Hφ) (constant rate of inflaton roll). In addition, we briefly investigate the possible enhancement of super-horizon perturbations beyond the slow-roll approximation.

[en] We consider thermal, trapped and chromo-natural inflation in light of the swampland criteria and the Trans-Planckian Censorship Conjecture (TCC). Since thermal inflation occurs at energies low compared to those of Grand Unification, it is consistent with the TCC, and it is also consistent with the refined swampland conditions. Trapped and chromo-natural inflation are candidates for primordial (high energy scale) inflation. Since in both of these scenarios there are effective damping terms in the scalar field equation of motion, the models can easily be consistent with the swampland criteria. The TCC, on the other hand, constrains these scenarios to only take place at low energies.