具有Yukawa相互作用的G-本质

Quintessence with Yukawa Interaction

We consider a quintessence model for dark energy interacting with dark matter via a Yukawa interaction. To put constraints on this model we use the CMB measurements from the Planck satellite together with BAO, SNIa and $H_0$ data. We conclude that this is a viable model and an appropriate scalar potential can favor the interacting scenario.

Quantum corrected power spectra of massless minimally coupled scalars during inflation: Effects of Yukawa coupling versus quartic self-interaction

We, in the first part, contemplate a massless minimally coupled scalar which is Yukawa-coupled to a massless Dirac fermion in a locally de Sitter background of an inflating spacetime. We compute the scalar's quantum corrected mode function, power spectrum, spectral index and the running of the spectral index at one-loop order. We find that the spectrum is slightly blue-tilted; hence, the amplitudes of fluctuations grow slightly toward the smaller scales. Then, in the second part, we apply the computation method used in the first part to a massless minimally coupled scalar with a quartic self-i…

An exotic k-essence interpretation of interactive cosmological models

We define a generalization of scalar fields with non-canonical kinetic term which we call exotic k-essence or briefly, exotik. These fields are generated by the global description of cosmological models with two interactive fluids in the dark sector and under certain conditions, they correspond to usual k-essences. The formalism is applied to the cases of constant potential and of inverse square potential and also we develop the purely exotik version for the modified holographic Ricci type of dark energy (MHR), where the equations of state are not constant. With the kinetic function $F=1+mx$ a…

Kinetic k-essence ghost dark energy model

A ghost dark energy model has been recently put forward to explain the current accelerated expansion of the Universe. In this model, the energy density of ghost dark energy, which comes from the Veneziano ghost of QCD, is proportional to the Hubble parameter, $ρ_D=αH$. Here $α$ is a constant of order $Λ^3_{QCD}$ where $Λ_{QCD}\sim 100 MeV$ is the QCD mass scale. We consider a connection between ghost dark energy with/without interaction between the components of the dark sector and the kinetic k-essence field. It is shown that the cosmological evolution of the ghost dark energy dominated Unive…

具有汤川型相互作用的费米宇宙学

Fermionic cosmologies with Yukawa type interactions

在这项工作中，我们讨论了如果费米源可以负责加速周期的Friedmann-Robertson-Walker空间平坦的宇宙，包括一个通常的自相互作用势的Nambu-Jona-Lasinio型与费米标量相互作用势的汤川型。结果表明，这些势的组合可以促进一个最初的加速期，经过一个中间减速时代，与最终的永恒加速期，其中自相互作用的贡献占主导地位。

K-dynamics: well-posed 1+1 evolutions in K-essence

We study the vacuum Cauchy problem for K-essence, i.e. cosmologically relevant scalar-tensor theories that involve first-order derivative self-interactions, and which pass all existing gravitational wave bounds. We restrict to spherical symmetry and show that there exists a large class of theories for which no breakdown of the Cauchy problem occurs outside apparent black hole horizons, even in the presence of scalar shocks/caustics, except for a small set of initial data sufficiently close to critical black hole collapse. We characterise these problematic initial data, and show that they lead …

Ghost condensates and pure kinetic $k$-essence condensates in presence of field-fluid non-minimal coupling in the dark sector

In this article we try to find out the conditions when a ghost field in conjunction with a barotropic fluid produces a stable accelerating expansion phase of the universe. It is seen that in many cases the ghost field produces a condensate and drives the fluid energy density to zero in the final accelerating phase, but there can be other possibilities. We have shown that a pure kinetic $k$-essence field (which is not a ghost field) interacting with a fluid can also form an interaction induced condensate and produce a stable accelerating phase of the universe. In the latter case the fluid energ…

Condensed dark matter with a Yukawa interaction

We explore the possible phases of a condensed dark matter (DM) candidate taken to be in the form of a fermion with a Yukawa coupling to a scalar particle, at zero temperature but at finite density. This theory essentially depends on only four parameters, the Yukawa coupling, the fermion mass, the scalar mediator mass, and the DM density. At low fermion densities we delimit the Bardeen-Cooper-Schrieffer (BCS), Bose-Einstein Condensate (BEC) and crossover phases as a function of model parameters using the notion of scattering length. We further study the BCS phase by consistently including emerg…

Explain DAMPE Results by Dark Matter With Hierarchical Lepton-Specific Yukawa Interactions

We propose to interpret the DAMPE electron excess at 1.5 TeV through scalar or Dirac fermion dark matter (DM) annihilation with doubly charged scalar mediators that have lepton-specific Yukawa couplings. Hierarchy of such lepton-specific Yukawa couplings is generated through the Froggatt-Nielsen mechanism, so that the dark matter annihilation products can be dominantly electrons. Stringent constraints from LEP2 on intermediate vector boson production can be evaded in our scenarios. In the case of scalar DM, we discuss one scenario with DM annihilating directly to leptons and the other scenario…

Modified scaling in $k$-essence model in interacting dark energy - dark matter scenario

It has been shown by \textit{Scherrer and Putter et.al} that, when dynamics of dark energy is driven by a homogeneous $k-$essence scalar field $ϕ$, with a Lagrangian of the form $L = V_0F(X)$ with a constant potential $V_0$ and $X = \frac{1}{2}\nabla^μϕ\nabla_μϕ= \frac{1}{2}\dotϕ^2$, one obtains a scaling relation $X(dF/dX)^2 = Ca^{-6}$ , where $C$ is a constant and $a$ is the FRW scale factor of the universe. The separate energy conservation in the dark energy sector and the constancy of $k-$essence potential are instrumental in obtaining such a scaling. In this paper, we have shown that even…

早期结构形成因Yukawa力导致的磁产生

Magnetogenesis from early structure formation due to Yukawa forces

本文研究了早期宇宙中Yukawa相互作用诱导费米子微晕坍缩产生热火球并注入能量，证明该能量可部分转化为原初磁场，并估算其关联尺度与功率谱，指出其可能是天体物理磁场的种子。