We propose a minimal framework to address successful quartic inflation, dark matter (DM) production in the early universe and non-vanishing tiny Majorana neutrino mass from a common gravitational origin point of view. In this setup, the quartic inflation is revived successfully via non-minimal coupling of inflaton to gravity while the production of DM takes place from purely gravitational effects through a misalignment mechanism. The generation of light Majorana neutrino mass is aided by explicit breaking of global lepton number symmetry through Planck suppressed operators involving non-zero vacuum expectation value (VEV) of the inflaton field. We present a detailed study of the DM yield in presence of non-minimal inflation, considering both the metric and the Palatini formalisms of gravity wherever appropriate. We reach at some interesting and different results in the DM sector compared to the earlier works in the similar direction with minimal inflationary background. Restricting to the light DM regime ($\mathcal{O}(1)$ keV- $\mathcal{O}(100)$ MeV) where classical production is expected to dominate over the quantum production, we numerically predict the DM mass by varying the DM quartic and non-minimal coupling, to be consistent with relic density requirements. We also obtain some non-trivial dependence of DM phenomenology on some of the relevant parameters of the inflation sector {\it e.g.} non minimal coupling and inflaton VEV. To explore the dependence on inflationary parameters further, we also estimate the DM relic using the same mechanism for two other inflationary models consistent with latest data and observe that one of these models predicts different range of DM mass upto hundreds of TeV.
Quartic hilltop inflation remains one of the most successful inflationary models. Yet, the expectations of early treatments of hilltop inflation would contradict the observations and render the model excluded. However, recent numerical treatment has demonstrated that quartic hilltop inflation actually fares well with observations. In this work, a fully analytic treatment of the model aims to dispel the mystery surrounding the behaviour of quartic hilltop inflation. The results obtained are in excellent agreement with numerical works on the subject, yet offer simple analytic formulas to calcula…
We study models of quartic inflation where the inflaton field $ϕ$ is coupled non-minimally to gravity, $ξϕ^2 R$, and perform a study of quantum corrections in curved space-time at one-loop level. We specifically focus on comparing results between the metric and Palatini theories of gravity. Transformation from the Jordan to the Einstein frame gives different results for the two formulations and by using an effective field theory expansion we derive the appropriate $β$-functions and the renormalisation group improved effective potentials in curved space for both cases in the Einstein frame. In …
We show that if the inflaton has a non-minimal coupling to gravity and the Planck scale is dynamically generated, the results of Coleman-Weinberg inflation are confined in between two attractor solutions: quadratic inflation, which is ruled out by the recent measurements, and linear inflation which, instead, is in the experimental allowed region. The minimal scenario has only one free parameter -- the inflaton's non-minimal coupling to gravity -- that determines all physical parameters such as the tensor-to-scalar ratio and the reheating temperature of the Universe. Should the more precise fut…
After the release of the PLANCK data, it is evident that inflationary paradigm has stood the test of time. Even though, it is difficult to realise inflationary paradigm in a particle physics model as the present observations have ruled out the simplest quartic and quadratic inflationary potentials, which generically arise in particle physics. We would show that such simplest inflationary potentials can evade discrepancies with observations, if the inflaton field is assisted by another scalar during inflation. Moreover, unlike other multifield models, our model yields no isocurvature perturbati…
In this paper, I present an analytic solution to the equation of motion of the inflaton field in a model of rapid roll inflation with a quartic potential by assuming that the Hubble parameter is a constant during inflation. The result is obtained by using Jacobi elliptic functions. The spectral index $n_s$ and the running spectral index $n_s^\prime$ is obtained without using rapid roll or extended slow roll approximations. The cosmological consequences of the model is discussed.
It is well known that the non-minimal coupling $ξϕ^2R$ between the inflaton and the Ricci scalar affects predictions of single field inflation models. In particular, the $λϕ^4$ quartic inflation potential with $ξ\gtrsim0.005$ is one of the simplest models that agree with the current data. After reviewing the inflationary predictions of this potential, we analyze the effects of the radiative corrections due to couplings of the inflaton to other scalar fields or fermions. Using two different prescriptions discussed in the literature, we calculate the range of these coupling parameter values for …
We introduce warm quintessential inflation and study it in the weak dissipative regime. We consider the original quintessential inflation model, which approximates quartic chaotic inflation at early times and thawing quartic inverse-power-law quintessence at present. We find that the model successfully accounts for both inflation and dark energy observations, while it naturally reheats the Universe, thereby overcoming a major problem of quintessential inflation model-building.
We discuss how the non-minimal coupling $ξϕ^2 R$ between the inflaton and the Ricci scalar affects predictions of single field inflation models in Palatini formalism. To transition radiation dominated era, the inflaton field $ϕ$ must interact to matter fields at the end of inflation. Interactions of the inflaton with other fields lead to radiative corrections to the inflationary potential. These radiative corrections can be explained at leading order by Coleman-Weinberg (CW) one-loop corrections. In this work, using two different prescriptions debated in the literature, the effect of radiative…
We propose quartic inflation with non-minimal gravitational coupling in the context of the classically conformal U(1)_X extension of the SM. In this model, the U(1)_X gauge symmetry is radiatively broken through the Coleman-Weinberg (CW) mechanism, by which the U(1)_X gauge boson (Z' boson) and the right-handed neutrinos (RHNs) acquire their masses. We consider their masses in the range of O(10 GeV)-O(10 TeV), which are accessible to high energy collider experiments. The radiative U(1)_X gauge symmetry breaking also generates a negative mass squared for the SM Higgs doublet, and the electrowea…
We describe how quartic ($λϕ^4$) inflation with non-minimal coupling to gravity is realized in realistic supersymmetric $SO(10)$ models. In a well-motivated example the $16-\overline{16}$ Higgs multiplets, which break $SO(10)$ to $SU(5)$ and yield masses for the right-handed neutrinos, provide the inflaton field $ϕ$. Thus, leptogenesis is a natural outcome in this class of $SO(10)$ models. Moreover, the adjoint (45-plet) Higgs also acquires a GUT scale value during inflation so that the monopole problem is evaded. The scalar spectral index $n_s$ is in good agreement with the observations and $…
We confront the warm inflation observational predictions directly with the latest CMB data. We focus on a linear temperature (T) dissipative coefficient combined with the simplest model of inflation, a quartic chaotic potential. Although excluded in its standard cold inflation version, dissipation reduces the tensor-to-scalar ratio and brings the quartic chaotic model within the observable allowed range. We will use the CosmoMC package to derive constraints on the model parameters: the combination of coupling constants giving rise to dissipation, the effective number of relativistic degrees of…
We study the K-Inflation models where the inflaton field has non-canonical kinetic term. In particular, we consider the Dirac-Born-Infeld (DBI) form for the kinetic energy of the inflaton field. We consider quadratic and quartic potentials as well as the potential for the natural inflation. We use a modified version of the MODECODE (proposed by Mortonson et al.) to calculate the power spectrum of the primordial perturbations generated by the inflaton field and subsequently use the WMAP7 results to constrain the models. Interestingly with DBI type kinetic term, lesser gravity waves are produced…
We investigate the chaotic inflationary model using the two-loop effective potential of a self-interacting scalar field theory in curved spacetime. We use the potential which contains a non-minimal scalar curvature coupling and a quartic scalar self-interaction. We analyze the Lyapunov stability of de Sitter solution and show the stability bound. Calculating the inflationary parameters, we systematically explore the spectral index $n_s$ and the tensor-to-scalar ratio $r$, with varying the four parameters, the scalar-curvature coupling $ξ_0$, the scalar quartic coupling $λ_0$, the renormalizati…
We consider a supergravity model that has the modular $A_4$ symmetry and discuss the interplay between the neutrino mixing and inflation. The model contains right-handed neutrinos that have the Majorana masses and additional Yukawa couplings to the waterfall field. In the model an active neutrino is massless and we find that only the inverted hierarchy is allowed and the Majorana phase is predicted to be around $\pm (120\text{--}180)^\circ$ from the observed neutrino mixing data. In the early universe, one of right-handed sneutrinos plays the role of the inflaton field. Focusing on the subcrit…
Self-energies of a minimally coupled scalar field with quartic and trilinear interactions are calculated in a de Sitter background, using a position space propagator. For quartic interactions, we recover earlier results for the seagull diagram, namely that it contributes an effective mass for the scalar field at leading order in the infrared enhancement in a steady-state de Sitter background. We further show that the sunset diagram also contributes to this effective mass and argue that these two contributions are sufficient in order to determine a self-consistent dynamical mass. In addition, t…
Inflation models can be examined by the cosmological observations, WMAP, Planck, BICEP2 and so on. These observations directly constrain the spectral index, $n_s$, and the tensor-to-scalar ratio, $r$. Besides, from a theoretical point of view, it has been shown that any inflation models asymptote a universal attractor in $(n_s,r)$ plane for a larger scalar-gravity coupling. In this work we consider a simple chaotic inflation model with a scalar quartic and a scalar-curvature interactions. The quantum corrections are introduced for these interactions through the renormalization group. The infla…
We show that the Higgs portal interactions involving extra dark Higgs field can save generically the original Higgs inflation of the standard model (SM) from the problem of a deep non-SM vacuum in the SM Higgs potential. Specifically, we show that such interactions disconnect the top quark pole mass from inflationary observables and allow multi-dimensional parameter space to save the Higgs inflation, thanks to the additional parameters (the dark Higgs boson mass $m_ϕ$, the mixing angle $α$ between the SM Higgs $H$ and dark Higgs $Φ$, and the mixed quartic coupling) affecting RG-running of the …
Inflation occurring at energy densities less than (10$^{14}$ GeV)$^4$ produces tensor perturbations too small to be measured by cosmological surveys. However, we show that it is possible to probe low scale inflation by measuring the mass of the inflaton at low energy experiments. Detection prospects and cosmological constraints are determined for low scale quartic hilltop models of inflation paired with a curvaton field, which imprints the spectrum of scalar perturbations observed in large scale structure and on the cosmic microwave background. With cosmological constraints applied, low scale …
In this paper we propose two simple minimal Higgs inflation scenarios through a simple modification of the Higgs potential, as opposed to the usual non-minimal Higgs-gravity coupling prescription. The modification is done in such a way that it creates a flat plateau for a huge range of field values at the inflationary energy scale $μ\simeq (λ)^{1/4} α$. Assuming the perturbative Higgs quartic coupling, $λ\simeq {\cal O}(1)$, for both the models inflation energy scale turned out to be $μ\simeq (10^{14}, 10^{15})$ GeV, and prediction of all the cosmologically relevant quantities, $(n_s,r,dn_s^k)…
The inflaton necessary to implement the mechanism of inflationary cosmology has natural candidates in quiver gauge theory. We discuss the dimensionless coefficients of quartic couplings and enumerate scalars which are singlet under the low-energy gauge group. The inflaton mass is generally predicted to be in the TeV region, close to 4 TeV for one specific unified model. A quartic inflaton potential, and a mutated hybrid inflation, are discussed. They can give adequate inflation and appropriate fluctuations but different spectral indices.
We consider the Higgs inflation in the extension of the Standard Model with two Higgs doublets coupled to gravity non-minimally. In the presence of an approximate global U(1) symmetry in the Higgs sector, both radial and angular modes of neutral Higgs bosons drive inflation where large non-Gaussianity is possible from appropriate initial conditions on the angular mode. We also discuss the case with single-field inflation for which the U(1) symmetry is broken to a Z_2 subgroup. We show that inflationary constraints, perturbativity and stability conditions restrict the parameter space of the Hig…
We provide an update on five relatively well motivated inflationary models in which the inflaton is a Standard Model singlet scalar field. These include i) the textbook quadratic and quartic potential models but with additional couplings of the inflaton to fermions and bosons, which enable reheating and also modify the naive predictions for the scalar spectral index $n_s$ and $r$, ii) models with Higgs and Coleman-Weinberg potentials, and finally iii) a quartic potential model with non-minimal coupling of the inflaton to gravity. For $n_s$ values close to 0.96, as determined by the WMAP9 and P…
Inverted hybrid inflation (in which the inflaton field slowly rolls away from the origin, giving a spectral index $n\lsim 1$) is an appealing variant of the more usually studied hybrid model. Analysing the model alongside the ordinary hybrid case, we show that, in order to provide the correct density perturbations consistent with the COBE measurements, the dimensionless coupling constants of the inverted hybrid potential must be very small indeed. For example, the quartic coupling in a typical such potential is found to be $\lsim 10^{-12}$. A supersymmetric model of inverted hybrid inflation, …
We propose a chaotic inflation model in supergravity based on polynomial interactions of the inflaton. Specifically we study the chaotic inflation model with quadratic, cubic and quartic couplings in the scalar potential and show that the predicted scalar spectral index and tensor-to-scalar ratio can lie within the 1 sigma region allowed by the Planck results.
Inflection-point inflation is an interesting possibility to realize a successful slow-roll inflation when inflation is driven by a single scalar field with its initial value below the Planck mass ($ϕ_I \lesssim M_{Pl}$). In order for a renormalization group (RG) improved effective $λϕ^4$ potential to develop an inflection-point, the quartic coupling $λ(ϕ)$ must exhibit a minimum with an almost vanishing value in its RG evolution, namely $λ(ϕ_I) \simeq 0$ and $β_λ(ϕ_I) \simeq 0$, where $β_λ$ is the beta-function of the quartic coupling. As an example, we consider the minimal gauged $B-L$ extend…
We revisit a single field inflationary model based on Coleman-Weinberg potentials. We show that in small field Coleman-Weinberg inflation, the observed amplitude of perturbations needs an extremely small quartic coupling of the inflaton, which might be a signature of radiative origin. However, the spectral index obtained in a standard cosmological scenario turns out to be outside the 2 sigma region of the Planck data. When a non-standard cosmological framework is invoked, such as brane-world cosmology in the Randall-Sundrum model, the spectral index can be made consistent with Planck data with…
We derive lower bounds for the Higgs-curvature coupling from vacuum stability during inflation in three inflationary models: quadratic and quartic chaotic inflation, and Starobinsky-like power-law inflation. In contrast to most previous studies we take the time-dependence of the Hubble rate into account both in the geometry of our past light-cone and in the Higgs effective potential, which is approximated with three-loop renormalisation group improvement supplemented with one-loop curvature corrections. We find that in all three models, the lower bound is $ξ\gtrsim 0.051\ldots 0.066$ depending…
We consider the prescription dependence of the Higgs effective potential under the presence of general nonminimal couplings. We evaluate the fermion loop correction to the effective action in a simplified Higgs-Yukawa model whose path integral measure takes simple form either in the Jordan or Einstein frame. The resultant effective action becomes identical in both cases when we properly take into account the quartically divergent term coming from the change of measure. Working in the counterterm formalism, we clarify that the difference between the prescriptions I and II comes from the counter…
We provide a mechanism to obtain multiple inflection points for the inflaton potential based on the Coleman-Weinberg potential. The key ingredient is the existence of zeros of the inflaton quartic coupling beta function, which can be simply realized by a sign change of a gauge coupling beta function at a massive threshold scale in gauge-Yukawa models. A universal inflaton potential emerges for a wide range of models and can accommodate the experimental data in the small-field inflation scenario. While the ratio of tensor over scalar amplitudes is predicted to be small, the running of the scala…
Einstein-Cartan pseudoscalaron inflation, reheating and nonthermal leptogenesis
Istituto Nazionale di Astrofisica, Istituto di Astrofisica e Planetologia Spaziali (INAF-IAPS)（意大利国家天体物理研究所，天体物理学与行星科学研究所）；Federal University of Rio Grande do Norte（北里奥格兰德联邦大学）
A quartic, self-interacting potential in the induced gravity framework is known to have a pure de Sitter attractor for the homogeneous mode. In order to obtain non-zero slow roll parameters we therefore study the quantum back-reaction of the scalar and the tensor perturbations on such a homogeneous dynamics. The results are then compared with inflationary observables in order to constrain the parameters of the model.
We investigate the Higgs-Yukawa system with Majorana masses of a fermion within asymptotically safe quantum gravity. Using the functional renormalization group method we derive the beta functions of the Majorana masses and the Yukawa coupling constant and discuss the possibility of a non-trivial fixed point for the Yukawa coupling constant. In the gravitational sector we take into account higher derivative terms such as $R^2$ and $R_{μν}R^{μν}$ in addition to the Einstein-Hilbert term for our truncation. For a certain value of the gravitational coupling constants and the Majorana masses, the Y…
We study in detail (p)reheating after multi-field inflation models with a particular focus on N-flation. We consider a variety of different couplings between the inflatons and the matter sector, including both quartic and trilinear interactions with a light scalar field. We show that the presence of multiple oscillating inflatons makes parametric resonance inefficient in the case of the quartic interactions. Moreover, perturbative processes do not permit a complete decay of the inflaton for this coupling. In order to recover the hot big bang, we must instead consider trilinear couplings. In th…
The low reheat temperature at the end of inflation from the gravitino bound constrains the creation of heavy Majorana neutrinos associated with models of leptogenesis. However, a detailed view of the reheating of the Universe at the end of inflation implies that the maximum temperature during reheating, $\Tmax$, can be orders of magnitude higher than the final reheat temperature. This then allows for the production of the heavy Majorana neutrinos needed for leptogenesis. We carry out the complementary calculation of the gravitino production during reheating and its dependence on $\Tmax$. We fi…
We study preheating in the Palatini formalism with a quadratic inflaton potential and an added $αR^2$ term. In such models, the oscillating inflaton field repeatedly returns to the plateau of the Einstein frame potential, on which the tachyonic instability fragments the inflaton condensate within less than an e-fold. We find that tachyonic preheating takes place when $α\gtrsim 10^{13}$ and that the energy density of the fragmented field grows with the rate $Γ/H \approx 0.011 \times α^{0.31}$. The model extends the family of plateau models with similar preheating behaviour. Although it contains…
We study chaotic dynamics in preheating after inflation in which an inflaton $ϕ$ is coupled to another scalar field $χ$ through an interaction $(1/2)g^2ϕ^2χ^2$. We first estimate the size of the quasi-homogeneous field $χ$ at the beginning of reheating for large-field inflaton potentials $V(ϕ)=V_0ϕ^n$ by evaluating the amplitude of the $χ$ fluctuations on scales larger than the Hubble radius at the end of inflation. Parametric excitations of the field $χ$ during preheating can give rise to chaos between two dynamical scalar fields. For the quartic potential ($n=4$, $V_0=λ/4$) chaos actually oc…
We propose a novel reformulation of supersymmetric (more precisely $μ$-) hybrid inflation based on a local U(1) or any suitable extension of the minimal supersymmetric standard model (MSSM) which also resolves the $μ$ problem. We employ a suitable Kahler potential which effectively yields quartic inflation with non-minimal coupling to gravity. Imposing the gravitino Big Bang Nucleosynthesis (BBN) constraint on the reheat temperature ($T_r \lesssim 10^6$ GeV) and requiring a neutralino LSP, the tensor to scalar ratio ($r$) has a lower bound $r \gtrsim 0.004$. The U(1) symmetry breaking scale li…
We consider a phenomenological extension of the minimal supersymmetric standard model which incorporates chaotic inflation and a radiatively generated intermediate mass scale. Initially a period of chaotic inflation is driven by a quartic potential associated with the right-handed electron sneutrino. Supersymmetry relates the quartic coupling of the inflationary potential to the electron Majorana neutrino Yukawa coupling, $h_1$. The microwave background temperature anisotropy determines this coupling to be $h_1\simeq 10^{-7}$, which is similar in magnitude to the electron Dirac Yukawa coupling…
We consider the possibility that the majority of dark matter in our Universe consists of black holes of primordial origin. We determine the conditions under which such black holes may have originated from a single-field model of inflation characterized by a quartic polynomial potential. We also explore the effect of higher-dimensional operators. The large power spectrum of curvature perturbations that is needed for a large black hole abundance sources sizable second order tensor perturbations. The resulting stochastic background of primordial gravitational waves could be detected by the future…
State Key Laboratory of Dark Matter Physics, Tsung-Dao Lee Institute and School of Physics and Astronomy, Shanghai Jiao Tong University（上海交通大学物理与天文学院、李政道研究所暗物质全国重点实验室）；Key Laboratory for Particle Astrophysics and Cosmology (MOE), and Shanghai Key Laboratory for Particle Physics and Cosmology, Shanghai Jiao Tong University（上海交通大学粒子天体物理与宇宙学教育部重点实验室、上海粒子物理与宇宙学重点实验室）；School of Physics and Astronomy, University of Southampton（南安普顿大学物理与天文学院）；Dipartimento di Fisica e Astronomia “Galileo Galilei”, Università degli Studi di Padova（帕多瓦大学伽利略·伽利莱物理与天文系）；INFN, Sezione di Padova（意大利国家核物理研究所帕多瓦分部）；School of Fundamental Physics and Mathematical Sciences, Hangzhou Institute for Advanced Study, UCAS（中国科学院大学杭州高等研究院基础科学与数学学院）
Supersymmetric Unified theories which incorporate a renormalizable Type I seesaw mechanism for small neutrino masses can also provide slow roll inflection point inflation along a flat direction associated with a gauge invariant combination of the Higgs, slepton and right handed sneutrino superfields. Inflationary parameters are related to the Majorana and Dirac couplings responsible for neutrino masses with the scale of inflation set by a right-handed neutrino mass $M_{ν^c} \sim 10^6-10^{12}$ GeV. Tuning of the neutrino Dirac and Majorana superpotential couplings and soft Susy breaking paramet…
A new class of non-Gaussian curvature fluctuations ζ_{pr} (\bx) \equiv δN(χ_i) arises from the post-inflation preheating behaviour of a non-inflaton field χ_i. Its billiard-like chaotic dynamics imprints regular log-spaced narrow spikes in the number of preheating e-folds N(χ_i). We perform highly accurate lattice simulations of SUSY-inspired quartic inflaton and coupling potentials in a separate-universe approximation to compute N(χ_i) as a function of the (nearly homogeneous) initial condition χ_i. The super-horizon modes of χ_i(\bx) result in positive spiky excursions in ζ_{pr} and hence ne…
We revisit the hybrid inflation model gauged by $U(1)_{B-L}$ extension of the Minimal Supersymmetric Standard Model (MSSM) in a no-scale background. Considering a single predictive framework, we study inflation, leptogenesis, gavitino cosmology, and the stochastic background of gravitational waves produced by metastable cosmic strings. The spontaneous breaking of $U(1)_{B-L}$ at the end of inflation produces a network of metastable cosmic strings while, the interaction between $U(1)_{B-L}$ Higgs field and the neutrinos generate heavy Majorana masses for the right-handed neutrinos. The heavy Ma…
In supersymmetric theories, the signs of quartic terms in the Kähler potential control the stability of non-supersymmetric field configurations. In particular, in supersymmetric inflation models, the signs are important for the stability of an inflationary trajectory as well as for the prediction of the spectral index. In this paper, we clarify what properties of a UV theory determine the sign from unitarity arguments of scattering amplitudes. As non-trivial examples, we discuss the sign of a four-meson term in large $N$ supersymmetric gauge theories and also those of the quartic terms obtaine…
The amplitude of primordial curvature perturbations is enhanced when a radiation bath at a temperature T>H is sustained during inflation by dissipative particle production, which is particularly significant when a non-trivial statistical ensemble of inflaton fluctuations is also maintained. Since gravitational modes are oblivious to dissipative dynamics, this generically lowers the tensor-to-scalar ratio and yields a modified consistency relation for warm inflation, as well as changing the tilt of the scalar spectrum. We show that this alters the landscape of observationally allowed inflationa…
We consider an extended version of superconformal subcritical hybrid inflation model by introducing three right-handed neutrinos that have the Majorana mass terms. In the model one of the right-handed sneutrinos plays a role of the inflaton field, and it decays to reheat the universe after inflation. The vacuum expectation value for the waterfall field gives an unconventional pattern of the light neutrino mass matrix, and the neutrino Yukawa couplings that determine the reheating temperature are not constrained by the neutrino oscillation data. Consequently thermal leptogenesis or sneutrino le…
The issue of electroweak vacuum stability is studied in presence of a scalar field which participates in modifying the minimal chaotic inflation model. It is shown that the threshold effect on the Higgs quartic coupling originating from the Higgs-inflaton sector interaction can essentially make the electroweak vacuum stable upto the Planck scale. On the other hand we observe that the new physics parameters in this combined framework are enough to provide deviation from the minimal chaotic inflation predictions so as to keep it consistent with recent observation by Planck 2015.
We show that the recently proposed multi-natural inflation can be realized within the framework of 4D ${\cal N}=1$ supergravity. The inflaton potential mainly consists of two sinusoidal potentials that are comparable in size, but have different periodicity with a possible non-zero relative phase. For a sub-Planckian decay constant, the multi-natural inflation model is reduced to axion hilltop inflation. We show that, taking into account the effect of the relative phase, the spectral index can be increased to give a better fit to the Planck results, with respect to the hilltop quartic inflation…
Incorporating three generations of right-handed Majorana neutrinos to quintessential inflation, we construct a model which simultaneously explains inflation, dark energy, dark matter and baryogenesis. These neutrinos have hierarchical masses $M_3 \sim 10^{13}$GeV, $M_2 \sim 10^{11}$GeV, $M_1 \sim 10$keV and are produced by gravitational particle production in the kination regime after inflation. The heaviest, the intermediate, and the lightest account for reheating, CP violation of leptogenesis, and dark matter, respectively. This model can be tested in various ways with forthcoming observatio…
We analyse the effect of the non-minimal coupling of the form $ξϕ^2R/2$ on the single field inflation. If the non-minimal coupling is large, it relaxes the constraint on the field self coupling, making it possible to use the Standard Model Higgs field as the inflaton. At the same time, even small non-minimal coupling constant, $ξ\gtrsim10^{-3}$, brings the usual inflaton with quartic potential in agreement with the WMAP5 observations.
The measured value of the Higgs quartic coupling $λ$ is peculiarly close to the critical value above which the Higgs potential becomes unstable, when extrapolated to high scales by renormalization group running. It is tempting to speculate that there is an anthropic reason behind this near-criticality. We show how an axionic field can provide a landscape of vacuum states in which $λ$ scans. These states are populated during inflation to create a multiverse with different quartic couplings, with a probability distribution $P$ that can be computed. If $P$ is peaked in the anthropically forbidden…
