In this paper, we study the preinflationary dynamics for the power-law potential $[V(\varphi )\propto {\varphi }^n]$ with $n<2$ in the framework of loop quantum cosmology. When the kinetic energy of the inflaton initially dominates, the evolution of the Universe can always be divided into three different phases prior to preheating: bouncing, transition, and slow-roll inflation. During the bouncing phase, the evolution of the expansion factor is independent not only on the initial conditions but also the inflationary potentials and is given explicitly by an analytical solution. In contrast, for the potential energy dominated initial conditions, this universality is lost. We also obtain the total number of $e$-folds during the slow-roll inflation, whereby physically viable models are identified. In addition, we present phase space analysis for the inflationary potentials under consideration and compare our results with the ones obtained previously for different potentials.

We demonstrate that the Vlasov equation describing collisionless self-gravitating matter may be solved with the so-called Schrödinger method (ScM). With the ScM, one solves the Schrödinger-Poisson system of equations for a complex wave function in $d$ dimensions, rather than the Vlasov equation for a $2d$-dimensional phase space density. The ScM also allows calculating the $d$-dimensional cumulants directly through quasilocal manipulations of the wave function, avoiding the complexity of $2d$-dimensional phase space. We perform for the first time a quantitative comparison of the ScM and a conventional Vlasov solver in $d=2$ dimensions. Our numerical tests were carried out using two types of cold cosmological initial conditions: the classic collapse of a sine wave and those of a Gaussian random field as commonly used in cosmological cold dark matter N-body simulations. We compare the first three cumulants, that is, the density, velocity and velocity dispersion, to those obtained by solving the Vlasov equation using the publicly available code ColDICE. We find excellent qualitative and quantitative agreement between these codes, demonstrating the feasibility and advantages of the ScM as an alternative to N-body simulations. We discuss, the emergence of effective vorticity in the ScM through the winding number around the points where the wave function vanishes. As an application we evaluate the background pressure induced by the non-linearity of large scale structure formation, thereby estimating the magnitude of cosmological backreaction. We find that it is negligibly small and has time dependence and magnitude compatible with expectations from the effective field theory of large scale structure.

We present a detailed analysis of excited cosmic string solutions that possess superconducting currents. These currents can be excited inside the string core, and—if the condensate is large enough—can lead to the excitations of the Higgs field. Next to the case with global unbroken symmetry, we discuss also the effects of the gauging of this symmetry and show that excited condensates persist when coupled to an electromagnetic field. The space-time of such strings is also constructed by solving the Einstein equations numerically and we show how the local scalar curvature is modified by the excitation. We consider the relevance of our results on the cosmic string network evolution as well as observations of primordial gravitational waves and cosmic rays.

We derive the scalar potential in four spacetime dimensions from an eight-dimensional $(R+\gamma R^4-2\mathrm{\Lambda }-F_4^2)$ gravity model in the presence of the 4-form $F_4$, with the (modified gravity) coupling constant $\gamma$ and the cosmological constant $\mathrm{\Lambda }$, by using the flux compactification of four extra dimensions on a 4-sphere with the warp factor. The scalar potential depends upon two scalar fields: the scalaron and the 4-sphere volume modulus. We demonstrate that it gives rise to a viable description of cosmological inflation in the early universe, with the scalaron playing the role of inflaton and the volume modulus to be (almost) stabilized at its minimum. We also speculate about a possibility of embedding our model in eight dimensions into a modified eight-dimensional supergavity that, in its turn, arises from a modified eleven-dimensional supergravity.

We investigate the impact of a variety of analysis assumptions that influence cluster identification and location on the kinematic Sunyaev-Zel’dovich (kSZ) pairwise momentum signal and covariance estimation. Photometric and spectroscopic galaxy tracers from SDSS, WISE, and DECaLs, spanning redshifts $0.05<z<0.7$, are considered in combination with CMB data from Planck and WMAP. With two complementary techniques, analytic offset modeling and direct comparisons of brightest and central galaxy catalogs selected by the red-sequence matched-filter probabilistic percolation (redMaPPer) algorithm, we find that miscentering uncertainties average to $0.4-0.7\sigma$ for the Planck kSZ statistical error budget obtained with a jackknife (JK) estimator. We also find that JK covariance estimates are significantly more conservative than those obtained by cosmic microwave background (CMB) rotation methods. Using redMaPPer data, we concurrently compare the impact of photometric redshift errors and miscentering. At separations $<\sim 50\mathrm{Mpc}$, where the kSZ signal is largest, miscentering uncertainties can be comparable to JK errors, while photometric redshifts are lower but still significant. For the next generation of CMB and large scale structure surveys the statistical and photometric errors will shrink markedly. Our results demonstrate that uncertainties introduced through using galaxy proxies for cluster locations will need to be fully incorporated, and actively mitigated, for the kSZ to reach its full potential as a cosmological constraining tool for dark energy and neutrino physics.

We present new simulations of decaying hydromagnetic turbulence for a relativistic equation of state relevant to the early Universe. We compare helical and nonhelical cases either with kinetically or magnetically dominated initial fields. Both kinetic and magnetic initial helicities lead to maximally helical magnetic fields after some time, but with different temporal decay laws. Both are relevant to the early Universe, although no mechanisms have yet been identified that produce magnetic helicity with strengths comparable to the big bang nucleosynthesis limit at scales comparable to the Hubble horizon at the electroweak phase transition. Nonhelical magnetically dominated fields could still produce picoGauss magnetic fields under most optimistic conditions. Only helical magnetic fields can potentially have nanoGauss strengths at scales up to 30 kpc today.

LIGO-Virgo collaboration has found black holes as heavy as $M\sim 30M_{\odot }$ through the detections of the gravitational waves emitted during their mergers. Primordial black holes (PBHs) produced by inflation could be an origin of such BHs. While it is tempting to presume that these PBHs constitute all dark matter (DM), there exist a number of constraints for PBHs with $\mathcal{O}(10)M_{\odot }$ which contradict with the idea of PBHs as all DM. Also, it is known that weakly interacting massive particle (WIMP) that is a common DM candidate is almost impossible to coexist with PBHs. These observations motivate us to pursue another candidate of DM. In this paper, we assume that the string axion solving the strong $CP$ problem makes up all DM, and discuss the coexistence of string axion DM and inflationary PBHs for LIGO events.

A detection of a core-collapse supernova signal with an advanced LIGO and Virgo gravitational-wave detector network will allow us to measure astrophysical parameters of the source. In real advanced gravitational-wave detector data, there are transient noise artifacts that may mimic a true gravitational-wave signal. In this paper, we outline a procedure implemented in the supernova model evidence extractor (SMEE) that determines if a core-collapse supernova signal candidate is a noise artefact, a rapidly rotating core-collapse supernova signal, or a neutrino explosion mechanism core-collapse supernova signal. Further, we use the latest available three-dimensional gravitational-wave core-collapse supernova simulations, and we outline a new procedure for the rejection of background noise transients when only one detector is operational. We find the minimum signal-to-noise ratio needed to detect all waveforms is reduced when using three-dimensional waveforms as signal models.

Models of gravitational waveforms play a critical role in detecting and characterizing the gravitational waves (GWs) from compact binary coalescences. Waveforms from numerical relativity (NR), while highly accurate, are too computationally expensive to produce to be directly used with Bayesian parameter estimation tools like Markov-chain-Monte-Carlo and nested sampling. We propose a Gaussian process regression (GPR) method to generate reduced-order-model waveforms based only on existing accurate (e.g. NR) simulations. Using a training set of simulated waveforms, our GPR approach produces interpolated waveforms along with uncertainties across the parameter space. As a proof of concept, we use a training set of IMRPhenomD waveforms to build a GPR model in the 2-d parameter space of mass ratio $q$ and equal-and-aligned spin ${\chi }_1={\chi }_2$. Using a regular, equally-spaced grid of 120 IMRPhenomD training waveforms in $q\in [1,3]$ and ${\chi }_1\in [-0.5,0.5]$, the GPR mean approximates IMRPhenomD in this space to mismatches below $4.3\times {10}^{-5}$. Our approach could in principle use training waveforms directly from numerical relativity. Beyond interpolation of waveforms, we also present a greedy algorithm that utilizes the errors provided by our GPR model to optimize the placement of future simulations. In a fiducial test case we find that using the greedy algorithm to iteratively add simulations achieves GPR errors that are $\sim 1$ order of magnitude lower than the errors from using Latin-hypercube or square training grids.

Low-mass suspension systems with high-$Q$ pendulum stages are used to enable quantum radiation pressure noise limited experiments. Utilizing multiple pendulum stages with vertical blade springs and materials with high-quality factors provides attenuation of seismic and thermal noise; however, damping of these high-$Q$ pendulum systems in multiple degrees of freedom is essential for practical implementation. Viscous damping such as eddy-current damping can be employed, but it introduces displacement noise from force noise due to thermal fluctuations in the damping system. In this paper we demonstrate a passive damping system with adjustable damping strength as a solution for this problem that can be used for low-mass suspension systems without adding additional displacement noise in science mode. We show a reduction of the damping factor by a factor of 8 on a test suspension and provide a general optimization for this system.

A detailed study of the analytic structure of one-loop self energy graphs for neutral and charged $\rho$ mesons is presented at finite temperature and arbitrary magnetic field using the real time formalism of thermal field theory. The imaginary part of the self energy is obtained from the discontinuities of these graphs across the unitary and Landau cuts, which is seen to be different for ${\rho }^0$ and ${\rho }^{\pm }$. The magnetic field dependent vacuum contribution to the real part of the self energy, which is usually ignored, is found to be appreciable. A significant effect of temperature and magnetic field is seen in the self energy, spectral function, effective mass, and dispersion relation of ${\rho }^0$ as well as of ${\rho }^{\pm }$ relative to its trivial Landau shift. However, for charged $\rho$ mesons, on account of the dominance of the Landau term, the effective mass appears to be independent of temperature. The trivial coupling of the magnetic moment of ${\rho }^{\pm }$ with external magnetic field, when incorporated in the calculation, makes the ${\rho }^{\pm }$ condense at high magnetic field.

We study the productions of charmed baryons ${\overline{\mathrm{\Lambda }}}_c^{-}{\mathrm{\Lambda }}_c^{+}$, ${\overline{\mathrm{\Lambda }}}_c^{-}{\mathrm{\Sigma }}_c^{+}$, and ${\overline{\mathrm{\Sigma }}}^{-}{\mathrm{\Sigma }}_c^{+}$ in the antiproton-proton collisions within an effective Lagrangian model that has only the baryon-meson degrees of freedom and involves the physical hadron masses. The baryon production proceeds via the $t$-channel exchanges of $D^0$ and $D^{*0}$ mesons in the initial collision of the antiproton with the target proton. The distortion effects in the initial and final states are accounted for by using an eikonal approximation-based procedure. We find that the reaction amplitudes of all the production channels are dominated by the $D^{*0}$ meson-exchange diagrams. We discuss the relative roles of tensor and vector components of the $D^{*0}$ coupling in the $D^{*0}$ meson-exchange component of the total production cross sections. The magnitudes of the cross sections are predicted for each final state for the range of beam momenta of relevance to the $\overline{\mathrm{P}}\mathrm{ANDA}$ experiment.

Twisted kinks in the massless ${\mathrm{NJL}}_2$ model interpolate between two distinct vacua on the chiral circle. If one approaches the chiral limit from finite bare fermion masses $m_0$, the vacuum is unique and twist cannot exist. This issue is studied analytically in the nonrelativistic limit, using a no-sea effective theory. We conclude that even in the massless limit, the interpretation of the twisted kink has to be revised. One has to attribute the fermion number of the valence state to the twisted kink. Fermion density is spread out over the whole space due to the massless pion field. The result can be pictured as a composite of a twisted kink (carrying energy, but no fermion number) and a partial winding of the chiral spiral (carrying fermion number, but no energy). This solves at the same time the puzzle of missing baryons with fermion number $N_f<N$ in the massless ${\mathrm{NJL}}_2$ model.

We consider the standard model extension to explore the anomalous magnetic dipole moment of the muon. In the QED part of the theory for the $CP$ and $CPT$-even Lorentz parameter $c_{\mu \nu }$, all independent electromagnetic form factors depend on a new scalar as $p^{\prime }.c.p$. Therefore, the form factors, even in zero momentum transfer, can be energy dependent. We examine the magnetic form factor to find such an energy dependent up to the one loop level at the leading order of $c_{\mu \nu }$. We show that at the high energy limit (but low enough to satisfy $p^2/m^2\ll 1$) there is an enhancement on the muon anomalous magnetic moment. For the first time, we find a bound on the $c_{\mu \nu }$ components for the muon as $[c_{TT}+0.35(c_{XX}+c_{YY})+0.28c_{ZZ}]$, which is about ${10}^{-11}$ in a terrestrial experiment.

We consider a scenario of a composite Higgs arising from a strong sector. We assume that the lowest lying composite states are the Higgs scalar doublet and a massive vector triplet, the dynamics below the compositeness scale of which are described in terms of an effective Lagrangian. Electroweak symmetry breaking takes place through a vacuum expectation value just as in the Standard Model, but with the vector resonances strongly coupled to the Higgs field. We determine the constraints on this scenario imposed by (i) the Higgs diphoton decay rate, (ii) the electroweak precision tests, and (iii) searches of heavy resonances at the LHC in the final states $l^{+}{l}^{-}$ and $l{\nu }_l$ ($l=e$, $\mu$), ${\tau }^{+}{\tau }^{-}$, $jj$, $t\overline{t}$, $WZ$, $WW$, $WH$, and $ZH$. We find that the heavy vector resonances should have masses in the range 2–3 TeV. In addition, the mixing of the heavy vectors with the Standard Model gauge bosons should be below $\tan \vartheta \sim 0.3$, which is consistent with the original assumption that the Higgs couples weakly to the Standard sector and strongly to the heavy vector resonances.

We study Lorentz violation effects on flavor transitions of high energy astrophysical neutrinos. It is shown that the appearance of a Lorentz-violating Hamiltonian can drastically change the flavor transition probabilities of astrophysical neutrinos. Predictions of Lorentz-violation effects on flavor compositions of astrophysical neutrinos arriving on Earth are compared with IceCube flavor composition measurement which analyzes astrophysical neutrino events in the energy range between 25 TeV and 2.8 PeV. Such a comparison indicates that the future IceCube-Gen2 will be able to place stringent constraints on a Lorentz-violating Hamiltonian in the neutrino sector. We work out the expected sensitivities by IceCube-Gen2 on dimension-3 $CPT$-odd and dimension-4 $CPT$-even operators in a Lorentz-violating Hamiltonian. The expected sensitivities can improve on the current constraints obtained from other types of experiments by more than two orders of magnitudes for certain ranges of the parameter space.

In the framework of the type-II two-Higgs-doublet model with a scalar dark matter ($S$), we examine the wrong sign Yukawa coupling of the 125 GeV Higgs, which is the only portal between the dark matter and standard model (SM) sectors. After imposing the constraints from the Higgs searches at the LHC and dark matter experiments, we obtain some interesting observables: (i) The theory, the oblique parameters, and the Higgs searches at the LHC can impose stringent constraints on $\tan \beta$ in the case of the wrong sign Yukawa coupling of the 125 GeV Higgs. For example, for $m_H=600\mathrm{GeV}$ and $140\mathrm{GeV}<m_A<200\mathrm{GeV}$, $\tan \beta$ is required to be in the range of 4.2 and 5.7. (ii) Because of the contribution of the $SS\to AA$ annihilation channel to the relic density, the dark matter coupling with the 125 GeV Higgs can be sizably suppressed. However, the $SS\to AA$ channel cannot solve the tension between the relic density and the signal data of 125 GeV Higgs for $m_S<50\mathrm{GeV}$. (iii) The limits of XENON1T (2017) and PandaX-II (2017) exclude most of the samples in the ranges of $65\mathrm{GeV}<m_S<78\mathrm{GeV}$, $0.8<f^n/f^p<1$, and $y_d/y_u>-0.82$. (iv) The Fermi-LAT limits exclude most of the samples in the range of $62.5\mathrm{GeV}<m_S<65\mathrm{GeV}$, including the samples with $f^n/f^p\sim -0.7$.

Motivated by an anomaly observed in the decay of an excited state of Beryllium (${}^8\mathrm{Be}$) by the Atomki collaboration, we study an extension of the standard model with a gauged $U(1{)}^{\prime }$ symmetry in presence of a two Higgs doublet model structure of the Higgs sector. We show that this scenario complies with a variety of experimental results and is able to explain the potential presence of a resonant spin-1 gauge boson, $Z^{\prime }$, with a mass of 17 MeV in the Atomki experimental data, for appropriate choices of $U(1{)}^{\prime }$ charges and Yukawa interactions.

We propose a minimal dark matter (MDM) scenario in the context of a simple gauge-Higgs unification (GHU) model based on the gauge group $SU(3)\times U(1{)}^{\prime }$ in five-dimensional Minkowski space with a compactification of the fifth dimension on the $S^1/Z_2$ orbifold. A pair of vectorlike $SU(3)$ multiplet fermions in a higher-dimensional representation is introduced in the bulk, and the DM particle is identified with the lightest mass eigenstate among the components in the multiplets. In the original model description, the DM particle communicates with the Standard Model (SM) particles only through the bulk gauge interaction, and hence our model is the GHU version of the MDM scenario. There are two typical realizations of the DM particle in four-dimensional effective theory: (i) the DM particle is mostly composed of the SM $SU(2{)}_L$ multiplets, or (ii) the DM is mostly composed of the SM $SU(2{)}_L$ singlets. Since the case (i) is very similar to the original MDM scenario, we focus on the case (ii), which is a realization of the Higgs-portal DM scenario in the context of the GHU model. We identify an allowed parameter region to be consistent with the current experimental constraints, which will be fully covered by the direct dark matter detection experiments in the near future. In the presence of the bulk multiplet fermions in higher-dimensional $SU(3)$ representations, we reproduce the 125 GeV Higgs boson mass through the renormalization group evolution of Higgs quartic coupling with the compactification scale of 10–100 TeV.

We study the direct detection prospects for a representative set of simplified models of sub-GeV dark matter (DM), accounting for existing terrestrial, astrophysical and cosmological constraints. We focus on dark matter lighter than an MeV, where these constraints are most stringent, and find three scenarios with accessible direct detection cross sections: (i) DM interacting via an ultralight kinetically mixed dark photon, (ii) a DM subcomponent interacting with nucleons or electrons through a light scalar or vector mediator, and (iii) DM coupled with nucleons via a mediator heavier than $\sim 100\mathrm{keV}$.