Narrow Results

Assuming our physical universe processes and registers information to determine its dynamical evolution, one can put serious constraints on the cosmology that our universe can bear, in particular, the origin of cosmic inflation. The universe evolves to gain her computation capacity which is linear in time t. On the other hand, the growth in content of degrees of freedom (i.e. by integrating in more galaxies) is as t^3/2 through expansion. When the in flux of degrees of freedom of the universe grows beyond some value, the computation capacity of the universe becomes insufficient to determine its evolution, the universe fixes its Hubble radius and inflates away its degrees of freedom within its horizon to regain dynamical evolution. The length of inflation is determined by the communication time required by the universe to become aware of the dropping in the degrees of freedom below some critical value by inflation and is proportional to its Hubble radius. We predict that there can be multiple cosmic inflations. The next inflation era will stop after inflating for a period of 10¹⁹ sec if the past inflation period of our universe was 10^-33 sec.

In this paper, inflation in the framework of Einstein–Cartan theory is revisited. Einstein–Cartan theory is a natural extension of the General Relativity with nonvanishing torsion. The connection on Riemann–Cartan space–time is only compatible with the cosmological principal for a particular form of torsion. We also show this form to be compatible with gauge invariance principle for non-Abelian and Abelian gauge fields under a certain deviced coupling procedure. We adopt an Abelian gauge field in the form of “cosmic triad”. The dynamical field equations are obtained and shown to sustain cosmic inflation with a large number of e-folds. We emphasize that at the end of inflation, torsion vanishes and the theory of Einstein–Cartan reduces to the General Relativity with the usual FRW geometry.

We extend a classically scale invariant model where the electroweak symmetry breaking is triggered by the dynamical chiral symmetry breaking in a hidden QCD sector, and a real singlet scalar $S$ mediates these two sectors. Our model can explain cosmic inflation without unitarity violation in addition. Slow-roll inflation occurs along a valley in scalar potential. In the original model, the coupling $-{\lambda }_{HS}$ between the Higgs field $H$ and $S$ is always negative and therefore, the potential has its valleys in $H$-$S$ mixed directions. For large value of the top Yukawa coupling $y_t$, the potential along the valley becomes negative since the Higgs quartic coupling ${\lambda }_H$ becomes negative at inflationary scale. Then slow-roll inflation cannot occur. For inflation to definitely occur, we render the coupling $-{\lambda }_{HS}$ positive at inflationary scale and consider the $S$-inflation case. This is achieved by introducing a new singlet scalar $\eta$ with the large coupling ${\lambda }_{H\eta }$ to $H$. By this extension, ${\lambda }_H$ can also always be positive, and we consider this case as the simplest case. We consider inflation with the nonminimal coupling ${\xi }_S$ between $S$ and gravity. Although ${\xi }_S$ is large such as ${\xi }_S\simeq {𝒪}(10^3)$, unitarity is not violated since couplings between $S$ and other fields are sufficiently small. $\eta$ is odd under a new symmetry $Z_2$ not to mix with $H$ regardless of largeness of ${\lambda }_{H\eta }$. Because of this symmetry, $\eta$ may have its relic abundance ${\mathrm{\Omega }}_{\eta }{ĥ}^2$ comparable with the observational value ${\mathrm{\Omega }}^{\mathrm{\text{obs}}}{ĥ}^2\simeq 0.12$ of the dark matter relic abundance. However, the spin-independent elastic cross-section ${\sigma }_{\mathrm{\text{SI}}}^{\eta }$ of $\eta$ exceeds the observational bound ${\sigma }_{\mathrm{\text{SI}}}^{\mathrm{\text{obs}}}\sim {𝒪}(10^{-47})$ cm². Hence, we impose the resonance condition $m_{\eta }\simeq m_S/2$ and reduce ${\mathrm{\Omega }}_{\eta }{ĥ}^2$ to much smaller than ${\mathrm{\Omega }}^{\mathrm{\text{obs}}}{ĥ}^2$. Constraints from the electroweak scale physics and inflationary scale physics are much strong, and the allowed parameter space is very narrow.

We examine whether an extended scenario of a two-scalar-field model, in which a mixed kinetic term of canonical and phantom scalar fields is involved, admits the Bianchi type I metric, which is homogeneous but anisotropic spacetime, as its power-law solutions. Then, we analyze the stability of the anisotropic power-law solutions to see whether these solutions respect the cosmic no-hair conjecture or not during the inflationary phase. In addition, we will also investigate a special scenario, where the pure kinetic terms of canonical and phantom fields disappear altogether in field equations, to test again the validity of cosmic no-hair conjecture. As a result, the cosmic no-hair conjecture always holds in both these scenarios due to the instability of the corresponding anisotropic inflationary solutions.

In this paper, we study a single-field inflationary model modified by a nonminimal coupling term between the Ricci scalar $R$ and the scalar field $\phi$ in the context of constant-roll inflation. The first-order formalism is used to analyze the constant-roll inflation instead of the standard methods used in the literature. In principle, the formalism considers two functions of the scalar field, $W=W(\phi )$ and $Z=Z(\phi )$, which lead to the reduction of the equations of motion to first-order differential equations. The approach can be applied to a wide range of cosmological situations since it directly relates the function $W$ with Hubbles parameter $H$. We perform the inflationary analysis for power-law and exponential couplings, separately. Then, we investigate the features of constant-roll potentials as inflationary potentials. Finally, we compare the inflationary parameters of the models with the observations of Cosmic Microwave Background (CMB) anisotropies in view of realizing a physically motivated model.

In this paper, we would like to examine whether a novel Starobinsky–Bel–Robinson (SBR) gravity model admits stable exponential inflationary solutions with or without spatial anisotropies. As a result, we are able to derive an exact de Sitter inflationary to this SBR model. Furthermore, we observe that an exact Bianchi type I inflationary solution does not exist in the SBR model. However, we find that a modified SBR model, in which the sign of coefficient of $R^2$ term is flipped from positive to negative, can admit the corresponding Bianchi type I inflationary solution. Unfortunately, stability analysis using the dynamical system approach indicates that both of these inflationary solutions turn out to be unstable. Interestingly, we show that a stable de Sitter inflationary solution can be obtained in the modified SBR gravity.

In this paper, we present an introduction to cosmic inflation in the framework of Palatini gravity, which provides an intriguing alternative to the conventional metric formulation of gravity. In the latter, only the metric specifies the spacetime geometry, whereas in the former, the metric and the spacetime connection are independent variables—an option that can result in a gravity theory distinct from the metric one. In scenarios where the field(s) responsible for cosmic inflation are non-minimally coupled to gravity or the gravitational sector is extended, assumptions about the underlying gravitational degrees of freedom can have substantial implications for the observational effects of inflation. We examine this explicitly by discussing various compelling scenarios, such as Higgs inflation with a non-minimal coupling to gravity, Higgs inflation with a non-minimal derivative coupling, ${{ℛ}}^2$ inflation, and beyond. We also comment on reheating in these models. Finally, as an application of the general results of Palatini ${{ℛ}}^2$ inflation, we review a model of successful quintessential inflation, where a single scalar field acts initially as the inflaton and then becomes dynamical dark energy, in agreement will all experimental constraints.

We present the general discussion on the inflection point inflation with small or large inflaton fields and show the effects of reheating dynamics on the inflationary predictions. In order to compare the model predictions with precisely measured CMB anisotropies and constrain the inflation models, the knowledge of the reheating dynamics is required. Inflection point inflation extended to the trans-Planckian regime can accommodate a sizable tensor-to-scalar ratio at the detectable level in the future CMB experiments.

The development of experimental methods that distinguish between light from objects with a similar color temperature and polarization presents a significant practical problem. In this paper, we demonstrate that the two-point correlation function (and its resultant correlation length) of a black body with an extended angular spectrum significantly differs from that of a black body with a narrow angular one. Using these results, we discuss an interferometric method as a possible experimental tool for discriminating between objects with the same color temperature but having different angular spectra.

A nagging problem has existed in the way we regard the local physical world around us and the non-local universe at large since the very beginning development of our philosophical and scientific attitudes toward the external world. That problem deals with the dualistic way in which we parse the physical world itself through geometry. Geometry can be based upon two different elements: the extension- or metric-element of Riemann and the point-element. Riemannian geometry can be fixed by expanding it to include the point-element, but even that is not enough. A further physical advance can be made by adopting the idea of the 0-D point Void, first developed intuitively by Sperry Andrews, but understanding the physical role of the 0-D point Void can only be realized by expanding that notion by adopting the physical concept of a discrete geometrical point/twist. It is only when a discrete 0-D point/twist Void replaces the simple point-element missing in the Riemannian system of differential geometry of surfaces that post-modern physics fulfills its promise. Understanding the concept of a point-element, of course, is necessary to understand how the Riemannian geometry has been used in general relativity as well as how it can be expanded to unify all of modern physics, including quantum theory, under a single geometrical paradigm. Whether a scientist is considering the discrete point-particles of the Standard Model or the existence of point singularities in relativity theory, the concerns are exactly the same, which forces the concept of an individual 0-D discrete point void to the center of the unification process. In either case, the human Mind and Consciousness are perceiving and interpreting the physical/material world that science is attempting to theoretically describe so the ultimate question of Consciousness and how it interacts with the Mind/brain as well as our commonly experienced physical reality also needs to be answered within the context of the 0-D point/twist. In other words, this is the point (no pun intended) where scientific logic and non-scientific intuition come together to give a complete theoretical structure of our commonly shared physical reality. Toward that end, the only logical scientific precedent to understand anything like the 0-D point/twist in all of the history of science is only found in the notion of a tesseract, which dates from the late nineteenth century attempts to ‘realize’ the concept of a hyperspace in the absence of being able to detect them through astronomical observations so that a hyperspace geometry could be used to explain nature. The end product of understanding these concepts is a greater insight into how the single field theory explains a much wider range of physical phenomena than any single previous paradigm of physics.

Many scientists have come to believe that any true unification theory in physics must include a concept of consciousness as well as a model for the mind that interprets the external physical/material world. And, that number is growing. This physical model goes even further. The single field theory includes a physical model of the neural net and explains how mind and consciousness can emerge from the physics of living organisms. Yet it is general enough to assimilate more intuitive models such as Andrews’ 0-D point Void which witnesses and co-creates higher-dimensional Riemannian geometrical realities as well as other more generalized physical models of consciousness to form a truly synergistic model of reality. In other words, physical reality and the consciousness that perceives and interprets that reality both come from the same source, they are co-created at the very beginning of the universe. A singular discrete 0-D point/twist Void emerged within the absolute spaceless-timeless Void of nothingness that preceded everything and through a logical sequence of events produced everything that now exists as our universe. This synergistic model goes well beyond the simple notion of mind and consciousness as mere human bound perceivers and interpreters of the external material/physical world by placing the physical origin of consciousness within every geometrical point in the universe itself. Although full blown consciousness itself is not everywhere in the universe–it is not a property of every bit of matter we observe or event that we detect–the universal will of consciousness to emerge in all forms of life is everywhere in the universe. This physical model clearly demonstrates that the precursors to our experience of consciousness are fundamental elements and active participants in creating the physical world that we perceive and scientifically interpret through the application of physics.