Anisotropic constant-roll inflation for the Dirac–Born–Infeld model

In this paper, we study a non-canonical extension of a supergravity-motivated model acting as a vivid counterexample to the cosmic no-hair conjecture due to its unusual coupling between scalar and electromagnetic fields. In particular, a canonical scalar field is replaced by the string-inspired Dirac–Born–Infeld one in this extension. As a result, exact anisotropic inflationary solutions for this Dirac–Born–Infeld model are figured out under a constant-roll condition. Furthermore, numerical calculations are performed to verify that these anisotropic constant-roll solutions are indeed attractive during their inflationary phase.

The impact of deformed space–space parameters into canonical scalar field model with exponential potential. The case of spatially flat Friedmann–Lemaître–Robertson–Walker (FLRW) universe

In this work, we propose a model of noncommutative cosmology through the deformation of minisuperspace. We focus on an exponentially potential with a homogeneous scalar field minimally coupled to gravity in the spatially flat universe. To process, we use a particular case of noncommutativity by making a deformation of space coordinates only. Then, we compare results in both the commutative model and the noncommutative one.

Soliton, breather and shockwave solutions of the Heisenberg and the $$ T\overline{T} $$ deformations of scalar field theories in 1+1 dimensions

In this note we study soliton, breather and shockwave solutions in certain two dimensional field theories. These include: (i) Heisenberg’s model suggested originally to describe the scattering of high energy nucleons (ii) $$ T\overline{T} $$ T T ¯ deformations of certain canonical scalar field theories with a potential. We find explicit soliton solutions of these models with sine-Gordon and Higgs-type potentials. We prove that the $$ T\overline{T} $$ T T ¯ deformation of a theory of a given potential does not correct the mass of the soliton of the undeformed one. We further conjecture the form of breather solutions of these models. We show that certain $$ T\overline{T} $$ T T ¯ deformed actions admit shockwave solutions that generalize those of Heisenberg’s Lagrangian.

α-Attractors and reheating in a nonminimal inflationary model

We study [Formula: see text]-attractor models with both E-model and T-model potential in an extended Nonminimal Derivative (NMD) inflation where a canonical scalar field and its derivatives are nonminimally coupled to gravity. We calculate the evolution of perturbations during this regime. Then by adopting inflation potentials of the model we show that in the large [Formula: see text] and small [Formula: see text] limit, the value of the scalar spectral index [Formula: see text] and tensor-to-scalar ratio [Formula: see text] are universal. Next, we study reheating after inflation in this formalism. We obtain some constraints on the model’s parameter space by adopting the results with Planck 2018.

Nonlinear Schrödinger-type formulation of scalar field cosmology: Two barotropic fluids and exact solutions

Time-independent nonlinear Schrödinger-type (NLS) formulation of FRW cosmology with canonical scalar field is considered in the case of two barotropic fluids. We derived Friedmann formulation variables in terms of NLS variables. Seven exact solutions found by D’Ambroise [Ph.D. thesis, arXiv:1005.1410 ] and one new found solution are explored and tested in cosmology. The result suggests that time-independent NLS formulation of cosmology case should be upgraded to the time-dependent case.