Axion helioscopes aim to detect axions which are produced in the core of the Sun. Their spectrum contains information about the solar interior and could in principle help to solve the conflict between high and low metallicity solar models. Using the planned International Axion Observatory as an example, we show that helioscopes could measure the strength of characteristic emission peaks caused by the presence of heavier elements with good precision. In order to determine unambiguously the elemental abundances, an improved modeling of the states of atoms inside the solar plasma is required.

In this paper, we study the contribution of the chiral vortical effect, in addition to that of the chiral magnetic effect, to the evolution of the hypermagnetic field and the matter-antimatter asymmetry in the symmetric phase of the early Universe in the temperature range $100\mathrm{GeV}\le T\le 10\mathrm{TeV}$. We choose a fully helical Chern-Simons wave configuration for the velocity and the hypermagnetic vector potential fields. The latter makes the plasma forcefree in the absence of viscosity. We show that the most pronounced effect of the chiral vorticity is the production and initial growth of the hypermagnetic field. In particular, we show that in the presence of a nonzero matter asymmetry, the hypermagnetic field can grow from zero initial value only in the presence of a nonzero vorticity field. Moreover, we show that larger initial growths not only result in larger maximum values of the hypermagnetic field, but also cause the saturation of the hypermagnetic field and the conversion of the lepton-baryon asymmetry to occur more quickly, i.e., at a higher temperature. We show that the damping of the vorticity due to the presence of viscosity, which typically occurs extremely rapidly, does not significantly affect the evolution.

The Bloch theorem in ordinary quantum mechanics means the absence of the total electric current in equilibrium. In the present paper, we analyze the possibility that this theorem remains valid within quantum field theory relevant for the description of both high-energy physics and condensed matter physics phenomena. First of all, we prove that the total electric current in equilibrium is the topological invariant for the gapped fermions that are subject to periodical boundary conditions; i.e., it is robust to the smooth modification of such systems. This property remains valid when the interfermion interactions due to the exchange by bosonic excitations are taken into account perturbatively. We give the proof of this statement to all orders in perturbation theory. Thus, we prove the weak version of the Bloch theorem and conclude that the total current remains zero in any system, which is obtained by smooth modification of the one with the gapped charged fermions, periodical boundary conditions, and vanishing total electric current. We analyze several examples, in which the fermions are gapless. In some of them, the total electric current vanishes. At the same time, we propose the counterexamples of the equilibrium gapless systems, in which the total electric current is nonzero.

The correct quark and charged lepton mass matrices along with a nearly correct Cabibbo-Kobayashi-Maskawa (CKM) quark mixing matrix may be naturally accommodated in a Pati-Salam model constructed from intersecting D6 branes on a $T^6/({\mathbb{Z}}_2\times {\mathbb{Z}}_2)$ orientifold. Furthermore, near-tribimaximal mixing for neutrinos may arise naturally due to the structure of the Yukawa matrices. Consistency with the quark and charged lepton mass matrices in combination with obtaining near-tribimaximal mixing fixes the Dirac neutrino mass matrix completely. Then, applying the seesaw mechanism for different choices of right-handed neutrino masses and running the obtained neutrino parameters down to the electroweak scale via the renormalization group equations, we are able to make predictions for the neutrino masses and mixing angles. We obtain lepton mixing angles which are close to the observed values, ${\theta }_{12}=33.8°\pm 1.2°$, ${\theta }_{23}=46.9°\pm 0.9°$, and ${\theta }_{13}=8.56°\pm 0.20°$. In addition, the neutrino mass-squared differences are found to be $\mathrm{\Delta }{m}_{32}^2=0.0025\pm 0.0001{\mathrm{eV}}^2$ and $\mathrm{\Delta }{m}_{21}^2=0.000075\pm 0.000003\mathrm{eV}$ with $m_1=0.0150\pm 0.0002\mathrm{eV}$, $m_2=0.0173\pm 0.0002\mathrm{eV}$, and $m_3=0.053\pm 0.002\mathrm{eV}$ so that ${\sum }_i{m}_i=0.085\pm 0.002\mathrm{eV}$, consistent with experimental observations.

A formulation of classical electrodynamics on an energy-momentum background of constant, nonzero curvature is given. The procedure consists of taking the formulation of standard electrodynamics in the energy-momentum representation, and promoting the energy-momentum vector to belong to a constant (nonzero) curvature space. In particular, special emphasis is given to the definition of the integration measure and the generalized Dirac’s delta function. Finally, simple physical problems such as plane waves (solutions outside sources) and point charges are discussed in this context, where the self-energy of a point charge is shown to be finite.

An analytical expression is obtained for the anomalous magnetic moment of an electron in a constant magnetic field in topologically massive two-dimensional electrodynamics. In the limiting case of a relatively weak magnetic field, asymptotic formulas are found, which specify the dependence of the anomalous magnetic moment on the Chern-Simons parameter and dynamic parameter of synchrotron radiation. The conditions are identified for the applicability of the computations of the anomalous magnetic moment of an electron, which have previously been made based on the calculation of the vertex function in two-dimensional electrodynamics with the Chern-Simons term.

We study the modulus stabilization in an $A_4$ model whose $A_4$ flavor symmetry is originated from the $S_4$ modular symmetry. We can stabilize the modulus so that the $A_4$ invariant superpotential leads to the realistic lepton masses and mixing angles. We also discuss the phenomenological aspect of the present model as a consequence of the modulus stabilization.

We have analyzed identified particle transverse momentum spectra in high multiplicity events in $pp$ collisions at LHC energies $\sqrt{s}=0.9–13\mathrm{TeV}$ published by the CMS Collaboration using the color string percolation model (CSPM). In CSPM color strings are formed after the collision, which decay into new strings through color neutral $q-\overline{q}$ pairs production. With the increase in the $pp$ collisions energy number of strings grow and randomly statistically overlap producing higher string tension of the composite strings. The net color in the overlap string area is a vector sum of the randomly oriented strings. The Schwinger color string breaking mechanism produces these color neutral $q-\overline{q}$ pairs at time $\sim 1\mathrm{fm}$/c, which subsequently hadronize. The initial temperature is extracted both in low and high multiplicity events.The shear viscosity to entropy density ratios $\eta /s$ are obtained as a function of temperature. For the higher multiplicity events at $\sqrt{s}=7$ and 13 TeV the initial temperature is above the universal hadronization temperature and is consistent with the creation of deconfined matter. The $\eta /s$ is similar to that in $\mathrm{Au}+\mathrm{Au}$ collisions at $\sqrt{s_{NN}}=200\mathrm{GeV}$. The small value of $\eta /s$ above the universal hadronization temperature suggested that the matter is a strongly coupled quark gluon plasma. In these small systems it can be argued that the thermalization is a consequence of the quantum tunneling through the event horizon introduced by the quarks confined in the colliding nucleons and their deceleration due to string formation, in analogy to the Hawking-Unruh radiation which provides a stochastic approach to equilibrium. The disk areas cluster on the nucleon transverse collision area. At the $2D$ percolation threshold a macroscopic spanning cluster suddenly occurs at the temperature $T_i=T_h$, representing a small connected droplet of $q-\overline{q}$ pairs, the quark-gluon plasma (QGP). $T_h$ is the universal hadronization temperature $\sim 167.7\mathrm{MeV}$. The collision energy dependent buildup of the 2D percolation clusters defines the temperature range $159\pm 9\mathrm{MeV}$ of the crossover transition between hadrons to the QGP in reasonable agreement with the lattice quantum chromodynamics (LQCD) pseudocritical temperature value of $155\pm 9\mathrm{MeV}$. Color string percolation model is the new initial stage paradigm for the study of the high density matter produced in $pp$ and $A+A$ collisions. With CSPM we can directly explore the thermodynamics of the QGP above the universal hadronization temperature.

The ratios ${\rho }_{\overline{p}p}^{pp}(s)$ of the real to the imaginary part of forward elastic $pp$ and $\overline{p}p$ scattering amplitudes at very high energies are considered in the models with rising total cross sections and its difference. It is shown from the dispersion relations for $pp$ and $\overline{p}p$ scattering amplitudes that in the Froissaron and maximal odderon approach the ratios do not vanish asymptotically and they have the opposite signs for $pp$ and $\overline{p}p$ scattering.

A symmetry-preserving approach to the two valence-body continuum bound-state problem is used to calculate the elastic electromagnetic form factors of the $\rho$-meson and subsequently to study the evolution of vector-meson form factors with current-quark mass. To facilitate a range of additional comparisons, $K^{*}$ form factors are also computed. The analysis reveals that vector mesons are larger than pseudoscalar mesons; composite vector mesons are nonspherical, with magnetic and quadrupole moments that deviate $\sim 30\%$ from point-particle values; in many ways, vector-meson properties are as much influenced by emergent mass as those of pseudoscalars; and vector-meson electric form factors possess a zero at spacelike momentum transfer. Qualitative similarities between the electric form factors of the $\rho$ and the proton, $G_E^p$, are used to argue that the character of emergent mass in the Standard Model can force a zero in $G_E^p$. Moreover, the existence of a zero in vector-meson electric form factors entails that a single-pole vector-meson dominance model can only be of limited use in estimating properties of off-shell vector mesons, providing poor guidance for systems in which the Higgs mechanism of mass generation is dominant.

An accurate prediction of the geoneutrino signal from the crust serves as a necessary prerequisite in the determination of the geoneutrino flux from the mantle. In this work we report the non-negligible effect associated to the exact three-flavor antineutrino survival probability in the calculation of the crustal geoneutrino signal, which was usually approximated as a constant average in previous studies. A geoneutrino signal underestimation of about 1–2 TNU is observed as a result of the oscillatory behavior within the local crustal region extending for about 300 km from the experimental site. We also estimated that the Mikheyev-Smirnov-Wolfenstein matter oscillation is responsible for a 0.1%–0.3% increase of the local crustal signal, depending on the detector location. This work reminds that the exact oscillation possibility in matter should be considered for future prediction of the local crustal geoneutrino signal.

According to the Schiff theorem, a static nuclear electric dipole moment (EDM) does not produce atomic and molecular EDMs. However, interaction with the axion dark matter field generates nuclear EDMs ${\mathbf{d}}_N={\mathbf{d}}_N^0\cos (\omega t)$ which oscillate with the frequency $\omega =m_a{c}^2/\hslash$. These oscillating nuclear EDMs generate atomic and molecular EDMs proportional to ${\omega }^2$. The resulting atomic and molecular EDMs do not, however, lead to nuclear spin rotation in constant external electric fields. On the other hand, an oscillating electric field penetrates atoms and molecules and can interact with nuclear EDMs. Moreover, if the nuclear EDM oscillation frequency is in resonance with the external field, nuclear spin rotation happens, with the rotation angle growing linearly with time.

This paper presents a nonperturbative treatment of strong-coupling induced effects in atom-field systems which cannot be seen in traditional perturbative treatments invoking compromising assumptions such as the Born-Markov, rotating wave, or Fermi Golden rule. We consider an atom whose internal degrees of freedom are modeled by a harmonic oscillator which is bilinearly coupled to a scalar quantum field, representing one of the two polarizations of an electromagnetic field. Because the whole system is Gaussian we can solve this problem exactly. Using the open quantum system conceptual framework and the influence functional formalism we derive the dynamics of the reduced density matrix for the atom which enables the calculation of atomic transition probability and other relevant physical quantities. Finding an exact solution to this problem has the distinct advantage of enabling one to capture fully the strong coupling regime and discover interesting effects such as spontaneous ground state excitation [R. Passante, T. Petrosky, and I. Prigogine, Long-time behaviour of self-dressing and indirect spectroscopy, Physica (Amsterdam) 218A, 437 (1995).] which is unfathomable in perturbative treatments. The conventional description of atomic-optical activities is predicated on the assumption that the state of the total atom-field system is a product state of the atomic excitations and the photon number states, an assumption which is valid only for vanishingly weak coupling. The correct energy eigenfunctions to use should be that of the Hamiltonian of the combined atom-field system. Other features associated with finite to strong coupling effects such as resonance peak broadening and transition from a gapped to a gapless spectrum can all be understood from this perspective. Finally, to put the issues in a proper perspective we take the perturbative limit of the exact results and compare them with those from conventional time-dependent perturbation theory (TDPT). This enables one to pin-point where the deficiencies of TDPT lie as one removes the ultraweak coupling assumption.

Horndeski theory is the most general scalar-tensor theory retaining second-order field equations, although the action includes higher-order terms. This is achieved by a special choice of coupling constants. In this paper, we investigate the thick brane system in reduced Horndeski theory, especially the effects of the nonminimal derivative coupling and the cubic Galileon term on thick brane. First, the equations of motion are presented and a set of analytic background solutions are obtained. Then, the effects of these two terms on the thick brane are analyzed. It is found that the background solutions become asymmetric with the presence of the cubic Galileon term. However, the energy density of the thick brane is still symmetric with or without this term and splits with the presence of the nonminimal derivative coupling. The stability of the thick brane under tensor perturbation is also considered. It is shown that the tachyon is absent and the graviton zero mode can be localized on the brane. The localized graviton zero mode recovers the four-dimensional Newtonian potential and the presence of the nonminimal derivative coupling results in a splitting of its wave function. Besides, the presence of the cubic Galileon term results in the asymmetry of the effective potential and zero mode of the graviton. The correction of the massive graviton Kaluza-Klein modes to the Newtonian potential is also analyzed briefly.

Mean motion resonances are commonly seen in planetary systems, e.g., in the formation of orbital structure of Jupiter’s moons and the gaps in the rings of Saturn. In this work we study their effects in fully relativistic systems. We consider a model problem with two stellar mass black holes orbiting around a supermassive black hole. By adopting a two timescale expansion technique and averaging over the fast varying orbital variables, we derive the effective Hamiltonian for the slowly varying dynamical variables. The formalism is illustrated with a $n_{\underset{\_}{\varphi }}:n_{\underset{\_}{r}}:n_{\varphi }=2:1:-2$ resonance in Schwarzschild spacetime, which naturally becomes the $3:2$ resonance widely studied in the Newtonian limit. We also derive the multibody Hamiltonian in the post-Newtonian regime, where the radial and azimuthal frequencies are different because of the post-Newtonian precession. The capture and breaking conditions for these relativistic mean motion resonances are also discussed. In particular, it is possible that pairs of stellar mass black holes surrounding the supermassive black hole are locked into resonances as they migrate toward the supermassive black hole. As the inner object enter the LISA band, the outer object could reside at a close distance that significantly affects the inner object’s gravitational waveform.

We study the energy-momentum tensor and helicity of gauge fields coupled through $g\varphi F\tilde{F}/4$ to a pseudoscalar field $\varphi$ driving inflation. Under the assumption of a constant time derivative of the background inflaton, we compute analytically divergent and finite terms of the energy density and helicity of gauge fields for any value of the coupling $g$. We introduce a suitable adiabatic expansion for mode functions of physical states of the gauge fields which correctly reproduces ultraviolet divergences in average quantities and identifies corresponding counterterms. Our calculations shed light on the accuracy and the range of validity of approximated analytic estimates of the energy density and helicity terms previously existed in the literature in the strongly coupled regime only, i.e., for $g\dot{\varphi }/(2H)\gg 1$. We discuss the implications of our analytic calculations for the backreaction of quantum fluctuations onto the inflaton evolution.

The effective dynamics of scalar-tensor theory (STT) in the Jordan frame is studied in the context of loop quantum cosmology with holonomy corrections. After deriving the effective Hamiltonian from the connection dynamics formulation, we obtain the holonomy-corrected evolution equations of STT on spatially flat Friedmann-Robterson-Walker background, which exhibit some interesting features unique to the Jordan frame of STT. In particular, the linear term of the cosine function appearing in the equations could lead to dynamics much different from the classical theory in the low-energy limit. In the latter part of this paper, we choose a particular model in STT—the Brans-Dicke theory to specifically illustrate these features. It is found that in Brans-Dicke theory the effective evolution equations can be classified into four different cases. Exact solutions of the Friedmann equation in terms of the internal time are obtained in these cases. Moreover, the solutions in terms of the proper time describing the late time evolution of the Universe are also obtained under certain approximation; in two cases the solutions coincide with the existing solutions in classical Brans-Dicke theory while in the other two cases the solutions do not.

We study generalized $P$ and $CP$ transformations in the three-Higgs-doublet model (3HDM) with Higgs and gauge fields only. We impose the requirement that applying such a transformation twice gives back the original fields, apart from possibly an $SU(2{)}_L\times U(1{)}_Y$ gauge transformation. We find that there are two equivalence classes, with respect to basis transformations, of generalized $P$ transformations, and there is only one class of $CP$ transformations. We discuss the conditions that the potential has to satisfy in order to be invariant under these transformations. We apply the method of bilinears, which we briefly review. We discuss the relation to the conventional basis, where the potential is written in terms of scalar products of the doublet fields. In particular, we give an explicit derivation of the result for the 3HDM (known for the analogous case of the THDM), that a potential is invariant under $CP$ transformations, satisfying the above requirement, if and only if there is a conventional basis where all parameters are real. This result no longer holds if the above requirement is dropped. Eventually, we study standard $P$ and $CP$ transformations in the $n$-Higgs-doublet model (nHDM). We show that for the bilinears of the nHDM, the standard $CP$ transformation corresponds to a diagonal linear transformation with only $\pm 1$ as diagonal elements. We give this matrix explicitly for arbitrary $n$.

Motivated by the short-baseline neutrino oscillation anomalies that suggest the existence of sterile neutrinos at the eV scale, we construct a scenario of a seesaw mechanism for $3+1$ light neutrinos implemented by warped compactification of an extra dimension. As the seesaw mechanism necessitates at least two right-handed neutrinos at mass scales much larger than eV, incorporating an eV-scale sterile neutrino into a seesaw entails large mass hierarchies among the singlet neutrinos. We show that such hierarchies can be naturally explained by moderate fluctuations of the five-dimensional fermion mass parameters.

We provide a holographic description of nonstrange multiquark exotics as compact topological molecules by binding heavy-light mesons to a tunneling configuration in $\mathrm{D}8\text{−}\mathrm{D}\overline{8}$ that is homotopic to the vacuum state with a fixed Chern-Simons number. In the tunneling process, the heavy-light mesons transmute to fermions. Their binding is generic and arises from a trade-off between the dipole attraction induced by the Chern-Simons term and the U(1) fermionic repulsion. In the heavy quark limit, the open-flavor tetraquark exotics $QQ\overline{q}\overline{q}$ and $\overline{Q}\overline{Q}qq$ emerge as bound Efimov states in a degenerate multiplet $I{J}^{\pi }=(00^{+},01^{+})$ with opposite intrinsic Chern-Simons numbers $\pm \frac{1}{2}$. The hidden-flavor tetraquark exotics such as $Q\overline{Q}q\overline{q}$, $QQ\overline{Q}\overline{q}$, and $QQ\overline{Q}\overline{Q}$ as compact topological molecules are unbound. Other exotics are also discussed.