We study the homologous collapse of stellar nuclear core, the virial theorem for hadron collisional relaxations, and photon productions from hadron collisions. We thus show the gravo-thermal dynamical process that transforms gravitational energy to p
hoton energy. The process is energetically and entropically favourable. The total baryon number conservation, Euler equation for energy-momentum conservation and Poissons equation for gravitational potential are adopted to describe homologous core collapses. The virial theorem determines the hadron collision energy gain from gravitational potential. The hadronic photon production rate determines the photon energy density. The time scales of macroscopic and microscopic processes are studied to verify approximations. As a result, we show the formation of opaque photon-pair spheres, whose total energy, size, temperature and number density, accounting for the main energetic features of Gamma-Ray Burst progenitors. We obtain the intrinsic correlations of these quantities. They depend only on the averaged thermal index of the stellar core. We discuss the possibility to confront them with observational data.
We study the Peccei-Quinn (PQ) symmetry of sterile right-handed neutrino sector and the gauge symmetries of the Standard Model (SM). Due to four-fermion interactions, spontaneous breaking of these symmetries at the electroweak scale generates top-qua
rk Dirac mass and sterile neutrino Majorana mass. The top quark channels yields massive Higgs, $W^pm$ and $Z^0$ bosons. The sterile neutrino channel yields the heaviest sterile neutrino Majorana mass, sterile Nambu-Goldstone axion (or majoron) and massive scalar $chi$boson ($m_chisim 10^2$ GeV). Their tiny couplings to SM particles are effectively induced by four-fermion operators. We show that such sterile axion is the PQ solution to the strong CP problem. The lightest sterile neutrino ($m_N^esim 10^2$ keV), sterile QCD axion ($m_a< 10^{-6}$ eV, $g_{agamma}< 10^{-13} {rm GeV}^{-1}$) and $chi$boson can be dark matter particle candidates, for their tiny couplings and long lifetimes inferred from the Xenon1T experiment. The axion and $chi$boson couplings to SM particles are below the values reached by current laboratory experiments and astrophysical observations for directly or indirectly detecting dark matter particles.
Sapcetime ${mathcal S}$ produces massive particle-antiparticle pairs $bar F F$ that in turn annihilate to spacetime. Such back and forth gravitational process ${mathcal S}Leftrightarrow bar F F$ is described by Boltzmann-type cosmic rate equation of
pair-number conservation. This cosmic rate equation, Einstein equation, and the reheating equation of pairs decay to relativistic particles completely determine the horizon $H$, cosmological energy density, massive pair and radiation energy densities in reheating epoch. Moreover, oscillating ${mathcal S}Leftrightarrow bar F F$ process leads to the acoustic perturbations of massive particle-antiparticle symmetric and asymmetric densities. We derive wave equations for these perturbations and find frequencies of lowest lying modes. Comparing their wavelengths with horizon variation, we show their subhorion crossing at preheating, and superhorizon crossing at reheating. The superhorizon crossing of particle-antiparticle asymmetric perturbations accounts for the baryogenesis of net baryon numbers, whose electric currents lead to magnetogenesis. The baryon number-to-entropy ratio, upper and lower limits of primeval magnetic fields are computed in accordance with observations. Given a pivot comoving wavelength, it is shown that these perturbations, as dark-matter acoustic waves, originate in pre-inflation and return back to the horizon after the recombination, possibly leaving imprints on the matter power spectrum at large length scales. Due to the Jeans instability, tiny pair-density acoustic perturbations in superhorizon can be amplified to the order of unity. Thus their amplitudes at reentry horizon become non-linear and maintain approximately constant physical sizes, and have physical influences on the formation of large scale structure and galaxies.
The cosmological energy density $rho_{_{_Lambda}}$ at the Planck scale $M_{rm pl}$ drives inflation and simultaneously reduces its value to create the pair-energy density $rho_{_{_M}}$ via the continuous pair productions of massive fermions and antif
ermions. The decreasing $rho_{_{_Lambda}}$ and increasing $rho_{_{_M}}$, in turn, slows down the inflation to its end when the pair production rate $Gamma_M$ is larger than the Hubble rate $H$ of inflation. A large number of massive pairs is produced and reheating epoch starts. In addition to the Einstein equation and energy-conservation law, we introduce the Boltzmann-type rate equation describing the number of pairs produced from (annihilating to) the spacetime, and reheating equation describing massive unstable pairs decay to relativistic particles and thermodynamic laws. This forms a close set of four independent differential equations uniquely determining $H$, $rho_{_Lambda}$, $rho_{_M}$ and radiation-energy density $rho_{_R}$, given the initial conditions at inflation end. Numerical solutions demonstrate three episodes of preheating, massive pairs dominate and genuine reheating. Results show that $rho_{_Lambda}$ can efficiently convert to $rho_{_M}$ by producing massive pairs, whose decay accounts for reheating $rho_{_R}$, temperature and entropy of the Big-Bang Universe. The stable massive pairs instead account for cold dark matter. Using CMB and baryon number-to-entropy ratio measurements, we constrain the effective mass of pairs, Yukawa coupling and degeneracies of relativistic particles. As a result, the obtained inflation $e$-folding number, reheating scale, temperature and entropy are in terms of the tensor-to-scalar ratio in the theoretically predicated range $0.042lesssim r lesssim 0.048$, consistently with current observations.
We present a possible understanding to the issues of cosmological constant, inflation, matter and coincidence problems based only on the Einstein equation and Hawking particle production. The inflation appears and results agree to observations. The C
MB large-scale anomaly can be explained and the dark-matter acoustic wave is speculated. The entropy and reheating are discussed. The cosmological term $Omega_{_Lambda}$ tracks down the matter $Omega_{_M}$ until the radiation-matter equilibrium, then slowly varies, thus the cosmic coincidence problem can be avoided. The relation between $Omega_{_Lambda}$ and $Omega_{_M}$ is shown and can be examined at large redshifts.
We study the impact of virtual axions on the polarization of photons inside a cavity during the interaction of high-power laser pulses. A novel detection scheme for measuring the axion-induced ellipticity signal during the Light-by-Light (LBL) scatte
ring process is investigated. We show that a momentum exchange between photons in a probe laser beam and a high-intensity target beam may lead to a resonance at the physical mass of the axion. Consequently, the resonant enhancement of vacuum birefringence gives rise to a large ellipticity signal. This signal enhancement can be applied in order to discriminate between the axion contribution to LBL scattering and the standard model contribution due to electron-positron pairs. The sensitivity of the scheme is studied for experimentally feasible probe light sources and ultrahigh intensity laser backgrounds. It is shown that this technique has the potential to probe the QCD axion in the mass range $10^{-2} textrm{eV} lesssim m_{a} lesssim 1 textrm{eV}$. In this region the axion induced signal surpasses the standard model background.
We investigate the stability and $e^+e^-$ pair creation of supercritically charged superheavy nuclei, $ud$QM nuggets, strangelets, and strangeon nuggets based on Thomas-Fermi approximation. The model parameters are fixed by reproducing their masses a
nd charge properties reported in earlier publications. It is found that $ud$QM nuggets, strangelets, and strangeon nuggets may be more stable than ${}^{56}$Fe at $Agtrsim 315$, $5times10^4$, and $1.2times10^8$, respectively. For those stable against neutron emission, the most massive superheavy element has a baryon number $sim$965, while $ud$QM nuggets, strangelets, and strangeon nuggets need to have baryon numbers larger than $39$, 433, and $2.7times10^5$. The $e^+e^-$ pair creation will inevitably start for superheavy nuclei with charge numbers $Zgeq177$, $ud$QM nuggets with $Zgeq163$, strangelets with $Zgeq 192$, and strangeon nuggets with $Zgeq 212$. A universal relation $Q/R_e = left(m_e - bar{mu}_eright)/alpha$ is obtained at a given electron chemical potential $bar{mu}_e$, where $Q$ is the total charge and $R_e$ the radius of electron cloud. This predicts the maximum charge number by taking $bar{mu}_e=-m_e$. For supercritically charged objects with $bar{mu}_e<-m_e$, the decay rate for $e^+e^-$ pair production is estimated based on the JWKB approximation. It is found that most positrons are emitted at $tlesssim 10^{-15}$ s, while a long lasting positron emission is observed for large objects with $Rgtrsim 1000$ fm. The emission and annihilation of positrons from supercritically charged objects may be partially responsible for the short $gamma$-ray burst during the merger of binary compact stars, the 511 keV continuum emission, as well as the narrow faint emission lines in X-ray spectra from galaxies and galaxy clusters.
Suppose that the early Universe starts with a quantum spacetime originated cosmological $Lambda$-term at the Planck scale $M_{rm pl}$. The cosmological energy density $rho_{_{_Lambda}}$ drives inflation and simultaneously reduces its value to create
the matter-energy density $rho_{_{_M}}$ via the continuous pair productions of massive fermions and antifermions. The decreasing $rho_{_{_Lambda}}$ and increasing $rho_{_{_M}}$, in turn, slows down the inflation to its end when the pair production rate $Gamma_M$ is larger than the Hubble rate $H$. The density $rho_{_{_Lambda}}$ and Hubble rate $H$ are uniquely determined by two independent equations from the Einstein equation and energy conservation law, besides the $rho_{_{_M}}$ is determined by pair productions. As a result, inflation naturally appears and theoretical results agree with Planck 2018 observations. Suppose that the reheating efficiently converts $rho_{_{_Lambda}}$ to $rho_{_{_M}}gg rho_{_{_Lambda}}$ accounting for the most relevant Universe mass, and some massive pairs decay to relativistic particles of energy density $rho_{_{_R}}$ starting the hot Big Bang. The back reaction $rho_{_{_M}}leftrightarrow Hleftrightarrow rho_{_{_Lambda}}$ is weak but continues. As a consequence, $rho_{_Lambda}$ closely tracks down $rho_{_R}$ from the reheating end up to the radiation-matter equilibrium, then it varies very slowly, $rho_{_Lambda}propto$ constant, due to the transition from radiation dominant epoch to matter dominant epoch. Therefore the cosmic coincidence problem can be possibly avoided.
Our goal is to understand the phenomena arising in optical lattice fermions at low temperature in an external magnetic field. Varying the field, the attraction between any two fermions can be made arbitrarily strong, where composite bosons form via s
o-called Feshbach resonances. By setting up strong-coupling equations for fermions, we find that in spatial dimension $d>2$ they couple to bosons which dress up fermions and lead to new massive composite fermions. At low enough temperature, we obtain the critical temperature at which composite bosons undergo the Bose-Einstein condensate (BEC), leading to BEC-dressing massive fermions. These form tightly bound pair states which are new bosonic quasi-particles producing a BEC-type condensate. A quantum critical point is found and the formation of condensates of complex quasi-particles is speculated over.
In the SM gauge symmetries and fermion content of neutrinos, charged leptons and quarks, we study the effective four-fermion operators of Einstein-Cartan type and their contributions to the Schwinger-Dyson equations of fermion self-energy functions.
The study is motivated by the speculation that these four-fermion operators are probably originated due to the quantum gravity that provides the natural regularization for chiral-symmetric gauge field theories. In the chiral-gauge symmetry breaking phase, as to achieve the energetically favorable ground state, only the top-quark mass is generated via the spontaneous symmetry breaking, and other fermion masses are generated via the explicit symmetry breaking induced by the top-quark mass, four-fermion interactions and fermion-flavor mixing matrices. A phase transition from the symmetry breaking phase to the chiral-gauge symmetric phase at TeV scale occurs and the drastically fine-tuning problem can be resolved. In the infrared fixed-point domain of the four-fermion coupling for the SM at low energies, we qualitatively obtain the hierarchy patterns of the SM fermion Dirac masses, Yukawa couplings and family-flavor mixing matrices with three additional right-handed neutrinos $ u^f_R$. Large Majorana masses and lepton-symmetry breaking are originated by the four-fermion interactions among $ u^f_R$ and their left-handed conjugated fields $ u^{fc}_R$. Light masses of gauged Majorana neutrinos in the normal hierarchy ($10^{-5}-10^{-2}$ eV) are obtained consistently with neutrino oscillations. We present some discussions on the composite Higgs phenomenology and forward-backward asymmetry of $tbar t$-production, as well as remarks on the candidates of light and heavy dark matter particles (fermions, scalar and pseudoscalar bosons).
