The first detection of a gravitational-wave signal of a coalescence of two black holes marked the beginning of the era of gravitational-wave astronomy, which opens exciting new possibilities in the fields of astronomy, astrophysics, and cosmology. The currently operating detectors of the LIGO and Virgo Collaborations are sensitive at relatively high frequencies, from 10 Hz up to about a kHz, and are able to detect gravitational waves emitted in a short time frame of less than a second (binary black holes) to minutes (binary neutron stars). Future missions like Laser Interferometer Space Antenna (LISA) will be sensitive in lower frequency ranges, which will make it possible to detect gravitational waves emitted long before these binaries merge. In this paper, we investigate the possibilities for parameter estimation using the Fisher-matrix formalism with combined information from present and future detectors in different frequency bands. The detectors we consider are the LIGO/Virgo detectors, the Einstein Telescope, LISA, and the first stage of the Deci-Hertz Interferometer Gravitational wave Observatory (B-DECIGO). The underlying models are constructed in time domain, which allows us to accurately model long-duration signal observations with multiband (or broadband) detector networks on parameter estimation. We assess the benefit of combining information from ground-based and space-borne detectors, and how choices of the orbit of B-DECIGO influence parameter estimates.

We present a new class of two-field inflationary attractor models, known as shift-symmetric orbital inflation, whose behavior is strongly multifield but whose predictions are remarkably close to those of single-field inflation. In these models, the field space metric and potential are such that the inflaton trajectory is along an “angular” isometry direction whose “radius” is constant but arbitrary. As a result, the radial (isocurvature) perturbations away from the trajectory are exactly massless and they freeze on superhorizon scales. These models are the first exact realization of the “ultra-light isocurvature” scenario, previously described in the literature, where a combined shift symmetry emerges between the curvature and isocurvature perturbations and results in primordial perturbation spectra that are entirely consistent with current observations. Due to the turning trajectory, the radial perturbation sources the tangential (curvature) perturbation and makes it grow linearly in time. As a result, only one degree of freedom (i.e., the one from isocurvature modes) is responsible for the primordial observables at the end of inflation, which yields the same phenomenology as in single-field inflation. In particular, isocurvature perturbations and local non-Gaussianity are highly suppressed here, even if the inflationary dynamics is truly multifield. We comment on the generalization to models with more than two fields.

An intense transient magnetic field is produced in high energy heavy-ion collisions mostly due to the spectator protons inside the two colliding nuclei. The magnetic field introduces anisotropy in the medium, and hence the isotropic scalar transport coefficients become anisotropic and split into multiple components. Here, we calculate the anisotropic transport coefficients’ shear, bulk viscosity, and electrical conductivity, and the thermal diffusion coefficients for a multicomponent hadron resonance gas (HRG) model for a nonzero magnetic field by using the Boltzmann transport equation in a relaxation time approximation (RTA). The anisotropic transport coefficient component along the magnetic field remains unaffected by the magnetic field, while perpendicular dissipation is governed by the interplay of the collisional relaxation time and the magnetic time scale, which is inverse of the cyclotron frequency. We calculate the anisotropic transport coefficients as a function of temperature and magnetic field using the HRG model. The neutral hadrons are unaffected by the Lorentz force and do not contribute to the anisotropic transports, we estimate within the HRG model the relative contribution of isotropic and anisotropic transports as a function of magnetic field and temperature. We also give an estimation of these anisotropic transport coefficients for the hadronic gas at finite baryon chemical potential (${\mu }_B$).

The Collins-Soper kernel relates transverse momentum-dependent parton distribution functions (TMDPDFs) at different energy scales. For small parton transverse momentum $q_T\sim {\mathrm{\Lambda }}_{\mathrm{QCD}}$, this kernel is nonperturbative and can only be determined with controlled uncertainties through experiment or first-principles calculations. This work presents the first exploratory determination of the Collins-Soper kernel using the lattice formulation of quantum chromodynamics. In a quenched calculation, the $N_f=0$ kernel is determined at scales in the range $250\mathrm{MeV}<q_T<2\mathrm{GeV}$, and an analysis of the remaining systematic uncertainties is undertaken.

Following the operator definition of the fragmentation function developed by Collins and Soper, we compute the gluon-to-$h_c$ fragmentation function at the lowest order in the velocity expansion in nonrelativistic QCD factorization approach. Utilizing some modern technique developed in the area of multiloop calculation, we are able to analytically deduce the infrared-finite color-singlet short-distance coefficient associated with the fragmentation function. The fragmentation probability for gluon into $h_c$ is estimated to be of the order of ${10}^{-6}$.

The emission of real photons from a momentum-anisotropic quark-gluon plasma (QGP) is affected by both the collective flow of the radiating medium and the modification of the local rest frame emission rate due to the anisotropic momentum distribution of partonic degrees of freedom. In this paper, we first calculate the photon production rate from an ellipsoidally momentum-anisotropic QGP including hard contributions from Compton scattering and quark pair annihilation and soft contribution calculated using the hard thermal loop approximation. We introduce a parametrization of the nonequilibrium rate in order to facilitate its further application in yield and flow calculations. We convolve the anisotropic photon rate with the space-time evolution of QGP provided by $3+1\mathrm{d}$ anisotropic hydrodynamics to obtain the yield and the elliptic flow coefficient $v_2$ of photons from QGP generated at Pb-Pb collisions at the LHC at 2.76 TeV and Au-Au collisions at the RHIC at 200 GeV. We investigate the effects of various parameters on the results. In particular, we analyze the sensitivity of the results to initial momentum anisotropy.

In this paper we derive the leading quantum gravitational corrections to the geodesics and the equations of motion for a scalar field in the spacetime containing a constant density star. It is shown that these corrections can be calculated in quantum gravity reliably and in a model independent way. Furthermore, we find that quantum gravity gives rise to an additional redshift that results from the gradient instead of the amplitude of the density profile.

In this work, we deal with vortices in Maxwell-Higgs or Chern-Simons-Higgs models that engender long range tails. We find first-order differential equations that support minimum energy solutions which solve the equations of motion. In the Maxwell scenario, we work with generalized magnetic permeabilities that lead to vortices described by solutions, magnetic field, and energy density with power-law tails that extend farther than the standard exponential ones. We also find a manner to obtain a Chern-Simons model with the same scalar and magnetic field profiles of the Maxwell case. By doing so, we also find vortices with the aforementioned long range feature, which is also present in the electric field in the Chern-Simons model. The present results may motivate investigations on nonrelativistic models, in particular in the case involving Rydberg atoms, which are known to present long range interactions and relatively long lifetimes.

We analyze the entanglement entropy, in real space, for the higher-dimensional integer quantum Hall effect on ${\mathbb{C}\mathbb{P}}^k$ (any even dimension) for Abelian and non-Abelian magnetic background fields. In the case of $\nu =1$ we perform a semiclassical calculation which gives the entropy as proportional to the phase-space area. This exhibits a certain universality in the sense that the proportionality constant is the same for any dimension and for any background, Abelian or non-Abelian. We also point out some distinct features in the profiles of the eigenfunctions of the two-point correlator that underline the difference in the value of entropies between $\nu =1$ and higher Landau levels.

Modified theories of gravity that offer viable models for dark energy often rely on mechanisms that screen their effects in high density environments. From this perspective, it would appear that, once solar system constraints are satisfied, these theories would predict a trivial phenomenology for (much denser) neutron stars. In this work we explore the fact that in scalar-tensor theories the scalar degree of freedom does not couple to the mass density alone, but to the trace of the energy-momentum tensor—which can increase and eventually change sign as density and pressure build up in the core of neutron stars—and investigate whether there could be a partial unscreening of the scalar field inside the most compact stars found in nature. For this purpose, we construct neutron star solutions with realistic equations of state in theories with screening mechanisms and study their stability under radial perturbations. In particular, we find that stable solutions with an unscreened core can exist in chameleon models, while for the environmentally dependent dilaton model a wealth of new, scalarized equilibrium solutions are found, some of which can be stable.

In this paper, we study the superradiant instabilities for the charged furry black hole in massive gravity. In de Rham-Gabadadze-Tolley (dRGT) theory, the Stückelberg field may provide Stückelberg hair for the black hole solutions. To make the furry most obvious in large scale, we only consider to the next order of $1/r^2$ in the metric function. According to the horizon, we define two new conservation charge as the hair of black hole: one is positive charge $k_{+}$; the other is negative charge $k_{-}$. Both of them are known as Stückelberg charge. Using a mirrorlike boundary condition, we show that there are superradiant instabilities for both types of black holes. As the Stückelberg charge increases, the central black hole becomes more stable. The reason for this behavior is caused by the impact of Stückelberg charge on the horizon. We also plot the parameter space for stabilities of two types black holes. As a matter of fact, the various configuration of Stückelberg field led to this new feature in the dRGT theory.

We study the constraint on the inflationary energy scale from the recently proposed trans-Planckian censorship conjecture (TCC). We find a universal upper bound on the inflationary Hubble expansion rate $H_{\inf }$ which is solely determined by the reheating temperature $T_{\mathrm{rh}}$: $H_{\inf }/M_{\mathrm{Pl}}\lesssim T_0/T_{\mathrm{rh}}$, where $T_0$ is the photon temperature today. The upper limit can be saturated by a postinflationary oscillatory stage with the critical equation-of-state parameter $w\approx -1/3$, or by an inflation model with multiple stages. In the lowest reheating temperature required for big bang nucleosynthesis, the upper bound on the tensor-to-scalar ratio $r$ at the CMB scales is $r\lesssim {10}^{-8}$, which can be realized in many string-inspired inflation models.

For a scalar theory with a global $O(N)$ symmetry, when $N=2$ a spatially inhomogeneous condensate arises when the term in the Lagrangian with two spatial derivatives has a negative coefficient. If the condensate for such a chiral spiral includes only one mode, characterized by a momentum $k_0\widehat{z}$, then in perturbation theory at nonzero temperature the propagator for the static mode has a double pole when ${\mathit{k}}^2=k_0^2$. We conjecture that since chiral spirals spontaneously break both global and spacetime symmetries, that such double poles are a universal property of their static transverse modes. Fluctuations from double poles generate linear infrared divergences in any number of spatial dimensions and disorder the condensate of chiral spirals, analogous to a type of quantum spin liquid. The characteristic feature of this region is that over large spatial distances the two point function is the usual exponential times an oscillatory function. We establish this at large $N$ and suggest that it occurs for all $N>2$. Implications for fermion models and the phase diagram of QCD at nonzero density are discussed.

We analyze the effect of the dark large mixing angle (DLMA) solution on the effective Majorana mass ($m_{\beta \beta }$) governing neutrinoless double beta decay ($0\nu \beta \beta$) in the presence of a sterile neutrino. We consider the $3+1$ picture, comprised of one additional sterile neutrino. We check that the Mikheyev-Smirnov-Wolfenstein resonance in the Sun can take place in the DLMA parameter space in this scenario. Next, we investigate how the values of the solar mixing angle ${\theta }_{12}$ corresponding to the DLMA region alter the predictions of $m_{\beta \beta }$ by including a sterile neutrino in the analysis. We also compare our results with three-generation cases for both standard large mixing angle (LMA) and DLMA. Additionally, we evaluate the discovery sensitivity of the future ${}^{136}Xe$ experiments in this context.

The lightest hidden-bottom tetraquarks in the dynamical diquark model fill an $S$-wave multiplet consisting of 12 isomultiplets. We predict their masses and dominant bottomonium decay channels using a simple three-parameter Hamiltonian that captures the core fine-structure features of the model, including isospin dependence. The only experimental inputs needed are the corresponding observables for $Z_b(10610)$ and $Z_b(10650)$. The mass of $X_b$, the bottom analogue to $X(3872)$, is highly constrained in this scheme. In addition, using lattice-calculated potentials we predict the location of the center of mass of the $P$-wave multiplet and find that $Y(10860)$ fits well but the newly discovered $Y(10750)$ does not, more plausibly being a $D$-wave bottomonium state. Using similar methods, we also examine the lowest $S$-wave multiplet of six $c\overline{c}s\overline{s}$ states, assuming as in earlier work that $X(3915)$ and $Y(4140)$ are members, and predict the masses and dominant charmonium decay modes of the other states. We again use lattice potentials to compute the centers of mass of higher multiplets and find them to be compatible with the masses of $Y(4626)$ ($1P$) and $X(4700)$ ($2S$), respectively.

In series of papers, the Boer-Mulders function for a given quark flavor has been extracted: (i) from data on semi-inclusive deep inelastic scattering, using the simplifying, but theoretically inconsistent, assumption that it is proportional to the Sivers function for each quark flavor and (ii) from data on Drell-Yan reactions. In earlier papers, using the semi-inclusive deep inelastic COMPASS deuteron data on the $⟨\cos {\varphi }_h⟩$ and $⟨\cos 2{\varphi }_h⟩$ asymmetries, we extracted the collinear $x_B$ dependence of the Boer-Mulders function for the sum of the valence quarks $Q_V=u_V+d_V$ using a small number of model dependent assumptions and found a significant disagreement with the analysis in (i). In the present paper, we provide a more complete analysis of the semi-inclusive deep inelastic scattering reaction, including a discussion of higher twist and interaction-dependent terms, and also a comparison with the Boer-Mulders function extracted from data on the Drell-Yan reaction. We confirm that the proportionality relation of the BM function to the Sivers function, for each quark flavor, fails badly, but find that it holds rather well if applied to the nonsinglet valence-quark combination, $Q_V$. We also find good agreement with the results of the Drell-Yan analysis. Furthermore, we obtain interesting information on the quark transverse momentum densities in the nucleon and on the hadron transverse momentum dependence in quark fragmentation.

Instead of the often used Foldy-Wouthuysen-Tani (FWT) transformation in nonrelativistic quantum chromodynamics (NRQCD), we take a more general relation between the relativistic and nonrelativistic on-shell spinors to recalculate the quark-quark-gluon vertex for heavy quarks. In comparison with the previous result using FWT, we obtain the high-order coefficients in the NRQCD Lagrangian up to $1/m^5$, where $m$ is the heavy quark mass.