In Advanced LIGO, detection and astrophysical source parameter estimation of the binary black hole merger GW150914 requires a calibrated estimate of the gravitational-wave strain sensed by the detectors. Producing an estimate from each detector’s differential arm length control loop readout signals requires applying time domain filters, which are designed from a frequency domain model of the detector’s gravitational-wave response. The gravitational-wave response model is determined by the detector’s opto-mechanical response and the properties of its feedback control system. The measurements used to validate the model and characterize its uncertainty are derived primarily from a dedicated photon radiation pressure actuator, with cross-checks provided by optical and radio frequency references. We describe how the gravitational-wave readout signal is calibrated into equivalent gravitational-wave-induced strain and how the statistical uncertainties and systematic errors are assessed. Detector data collected over 38 calendar days, from September 12 to October 20, 2015, contain the event GW150914 and approximately 16 days of coincident data used to estimate the event false alarm probability. The calibration uncertainty is less than 10% in magnitude and 10° in phase across the relevant frequency band, 20 Hz to 1 kHz.

We respond to a paper of Flambaum et al. [Phys. Rev. D 95, 058701 (2017).], claiming there is no effective induced oscillating electric dipole moment, e.g., for the electron, arising from interaction with an oscillating cosmic axion background via the anomaly. The relevant Feynman amplitude, Fig. 1, as computed by Flambaum et al., becomes a total divergence, and vanishes. Contrary to this result, we obtained a nonvanishing amplitude that yields physical electric dipole radiation for an electron (or any magnetic dipole moment) immersed in a cosmic axion field. We argue that Flambaum et al.’s counterclaim is incorrect, and is based upon a misunderstanding of a physics choice vs gauge choice, and an assumption that electric dipoles be defined only by coupling to static (constant in time) electric fields.

In the recent work [C. T. Hill, Phys. Rev. D 91, 111702(R) (2015).], C. Hill concludes that the axion electromagnetic anomaly induces an oscillating electron electric dipole moment of frequency $m_a$ and strength $\sim {10}^{-32}e\mathrm{cm}$, in the limit $v/c\to 0$ for the axion field. Here, we demonstrate that a proper treatment of this problem in the lowest order yields no electric dipole moment of the electron in the same limit. Instead, oscillating electric dipole moments of atoms and molecules are produced by different mechanisms.

A thermal model, based on the Tsallis distribution and blast-wave model, is proposed to compute hadron double-differential spectra $d^{2}N/d{p}_{\mathrm{T}}dy$ in $pp$ (also high-energy $p\overline{p}$) collisions. It successfully describes the available experimental data on pion and quarkonia [$\varphi$, $\mathrm{J}/\psi$, $\psi (2\mathrm{S})$, $\mathrm{\Upsilon }$ family] production at energies from $\sqrt{s}=5\mathrm{GeV}$ to the LHC ones. Simple parametrizations for the $\sqrt{s}$ dependence of the model parameters are provided, allowing predictions for the yields of these particles at new collision energies. The model can be used also for the pion Bose-Einstein correlation studies.

We probe the dimension-six operators contributing to Higgs production in association with a $Z$ boson at the future high-luminosity electron-positron colliders. Potential constraints on dimension-six operators in the Higgs sector are determined by performing a shape analysis on the differential angular distribution of the Higgs and $Z$ boson decay products. The analysis is performed at the center-of-mass energies of 350 and 500 GeV including a realistic detector simulation and the main sources of background processes. The 68% and 95% confidence level upper limits are obtained on the contributing anomalous couplings considering only the decay of the Higgs boson into a pair of b-quarks and leptonic $Z$ boson decay. Our results show that angular observables provide a great sensitivity to the anomalous couplings, in particular, at the high-luminosity regime.

In the littlest Higgs model with $T$ parity (LHT), we revisited $Zb\overline{b}$ couplings under current experimental constraints including the LHC Higgs data and the precision electroweak data. We study the LHT effects in the branching ratio $R_b$, the forward-backward asymmetry $A_{FB}^b$ and the left- and right-handed couplings $g_{Lb}$, $g_{Rb}$. We find that the LHT effects in $R_b$ are sizable enough to be observed at future $Z$-factories (ILC, CEPC, FCC-ee) in the allowed parameter space, while these effects in $A_{FB}^b$ are weak so that it is difficult to detect at the future experiments. The LHT model provides the large correction to the left-handed coupling $g_{Lb}$, which can be limited by current and future experiments.

Many models currently exist which attempt to interpret the excess of gamma rays emanating from the Galactic Center in terms of annihilating or decaying dark matter. These models typically exhibit a variety of complicated cascade mechanisms for photon production, leading to a nontrivial kinematics which obscures the physics of the underlying dark sector. In this paper, by contrast, we observe that the spectrum of the gamma-ray excess may actually exhibit an intriguing “energy-duality” invariance under $E_{\gamma }\to E_{*}^2/E_{\gamma }$ for some $E_{*}$. As we shall discuss, such an energy duality points back to a remarkably simple alternative kinematics which in turn is realized naturally within the Dynamical Dark Matter framework. Observation of this energy duality could therefore provide considerable information about the properties of the dark sector from which the Galactic Center gamma-ray excess might arise, and highlights the importance of acquiring more complete data for the Galactic Center excess in the energy range around 1 GeV.

In a recent study of the $\mathrm{\Lambda }(1405)$ the suppression of the strange-quark contribution to the magnetic form factor was interpreted as the discovery of a dominant antikaon-nucleon composition for this low-lying state. We confirm this result by calculating the light $u$ and $d$ quark contributions to the $\mathrm{\Lambda }(1405)$ magnetic form factor in lattice QCD in order to determine the extent to which their contributions support this exotic molecular description. Drawing on the recent graded-symmetry approach for the flavor-singlet components of the $\mathrm{\Lambda }(1405)$, the separation of connected and disconnected contributions is performed in both the flavor-octet and -singlet representations. In both cases, the disconnected-loop contributions are found to be large. The relationship between light-quark contributions to the $\mathrm{\Lambda }(1405)$ magnetic form factor and the connected contributions of the nucleon magnetic form factors is established and compared with lattice calculations of the same quantities, confirming the $\overline{K}N$ molecular structure of the $\mathrm{\Lambda }(1405)$ in lattice QCD.

Although the complex Langevin method can solve the sign problem in simulations of theories with complex actions, the method will yield the wrong results if known validity conditions are not satisfied. We present a novel method to compute observables for a target ensemble by reweighting complex trajectories generated with the complex Langevin method for an auxiliary ensemble having itself a complex action. While it is imperative that the validity conditions be satisfied for the auxiliary ensemble, there are no such requirements for the target ensemble. This allows us to enlarge the applicability range of the complex Langevin method. We illustrate this at the hand of a one-dimensional partition function and two-dimensional strong-coupling QCD.

Being interested in how a strongly coupled system approaches asymptotic freedom, we reexamine existing precision lattice QCD results for thermodynamic properties of the gluon plasma in a large temperature range. We discuss and thoroughly test the applicability of perturbative results, on which grounds we then infer that the pressure and other bulk properties approach the free limit somewhat slower than previously thought. We also revise the value of the first nonperturbative coefficient in the weak-coupling expansion.

It is well known that conformal embeddings can be used to construct nondiagonal modular invariants for affine Lie algebras. This idea can be extended to construct infinite series of nondiagonal modular invariants for coset conformal field theories (CFTs). In this paper, we systematically approach the problem of identifying higher-spin bulk duals for these kind of nondiagonal invariants. In particular, for a special value of the ’t Hooft coupling, there exist a class of partition functions that have enhanced supersymmetry, which should be reflected in a bulk dual. As an illustration of this, we show that a partition function of an orthogonal group coset CFT has an $\mathcal{N}=1$ supersymmetric higher-spin bulk dual, in the ’t Hooft limit. We also propose that two of the series of CFT partition functions, obtained from conformal embeddings, are equal, generalizing the well-known dual interpretation of the three-state Potts model as a $\frac{SU(2{)}_3\otimes SU(2{)}_1}{SU(2{)}_4}$ and also as a $\frac{SU(3{)}_1\otimes SU(3{)}_1}{SU(3{)}_2}$ coset model.

The stability criteria for the generalized Brans-Dicke cosmology in a spatially flat, homogeneous and isotropic cosmological model is discussed in the presence of a perfect fluid. The generalization comes through the channel that the Brans-Dicke coupling parameter $\omega$ is allowed to be a function of the scalar field $\varphi$. This generalization can lead to a host of scalar-tensor theories of gravity for various choices of $\omega =\omega (\varphi )$. A very interesting general result has been found. Excepting for the case of a radiation distribution as the choice of the fluid, all other solutions find a natural habitat in the corresponding solutions in general relativity in an infinite $\omega$ limit. For the radiation distribution, the dependence of stability on $\omega$ is a bit obscure. If a scalar potential, function of the Brans-Dicke scalar field, is added to the action, the requirement of an infinite $\omega$ for stability is relaxed for a matter distribution with a nonzero trace whereas it becomes a possibility for a radiation distribution.

In this work, inspired by the symmetron model, we analyze the evolution of spherical domain walls by considering specific potentials that ensure symmetry breaking and the occurrence of degenerate vacua that are necessary for the formation of domain walls. By considering a simple analytical model of spherical domain-wall collapse in vacuum, it is shown that this model fits the more accurate numerical results very well until full collapse, after which oscillations and scalar radiation take place. Furthermore, we explore the effect of a central nonrelativistic matter lump on the evolution of a spherical domain wall and show that the central lump can prevent the full collapse and annihilation of the domain-wall bubble, due to the repulsion between the domain wall and matter overdensity within the adopted symmetron-inspired model.

We study the instability of near extremal and extremal four-dimensional anti-de Sitter charged hairy black holes to radial neutral massive and charged massless scalar field perturbations. We solve the scalar field equation by using the improved asymptotic iteration method and the time domain analysis, and we find the quasinormal frequencies. For the charged scalar perturbations, we find the superradiance condition by computing the reflection coefficient in the low-frequency limit, and we show that in the superradiance regime, which depends on the scalar hair charge, all modes of radial charged massless perturbations are unstable, indicating that the charged hairy black hole is superradiantly unstable. On the other hand, calculating the quasinormal frequencies of radial neutral scalar perturbations in this background, we find stability of the charged hairy black hole.

We reconsider the long-range effects of the scattering of massless scalars and photons from a massive scalar object in quantum gravity. At the one-loop level, the relevant quantum mechanical corrections could be sorted into the graviton double-cut contributions, massless-scalar double-cut contributions and photon double-cut contributions. In Reference [N. E. J. Bjerrum-Bohr, J. F. Donoghue, B. R. Holstein, L. Planté, and P. Vanhove, Phys. Rev. Lett. 114, 061301 (2015), N. E. J. Bjerrum-Bohr, J. F. Donoghue, B. R. Holstein, L. Planté, and P. VanhoveJ. High Energy Phys. 11 (2016) 117] N. E. J. Bjerrum-Bohr et al. have considered explicitly the implications of the graviton double-cut contributions on the gravitational bending of light and some classical formulations of the equivalence principle, using the modern double-copy constructions and on-shell unitarity techniques. In this article, instead we consider all three contributions and redo the analysis using the traditional Feynman diagrammatic approach. Our results on the graviton double-cut contributions agree with the aforementioned references, acting as a nontrivial check of previous computations. Furthermore, it turns out that the massless-scalar double-cut contributions and the photon double-cut contributions do leave nonvanishing quantum effects on the scattering amplitudes and the gravitational bending of light. Yet, we find that the general structure of the gravitational amplitudes and the quantum discrepancy of the equivalence principle suggested in the aforementioned references remain intact.

It is shown that the correspondence principle and the holographic principle are incompatible in the background of an eternal Schwarzschild–anti–de Sitter geometry. The argument is based on the observation that algebraic structures of local quantum field and conformal field theory (CFT) operators are not equivalent. This implies, in particular, that the bulk CFT must be singular near the black-hole horizon. A CFT Hilbert space representation is elaborated which may correspond to the AdS black hole in the dual theory.

Exploring the characterization of singular black hole spacetimes, we study the relation between energy density, curvature invariants, and geodesic completeness using a quadratic $f(R)$ gravity theory coupled to an anisotropic fluid. Working in a metric-affine approach, our models and solutions represent minimal extensions of general relativity (GR) in the sense that they rapidly recover the usual Reissner-Nordström solution from near the inner horizon outwards. The anisotropic fluid helps modify only the innermost geometry. Depending on the values and signs of two parameters on the gravitational and matter sectors, a breakdown of the correlations between the finiteness/divergence of the energy density, the behavior of curvature invariants, and the (in)completeness of geodesics is obtained. We find a variety of configurations with and without wormholes, a case with a de Sitter interior, solutions that mimic nonlinear models of electrodynamics coupled to GR, and configurations with up to four horizons. Our results raise questions regarding what infinities, if any, a quantum version of these theories should regularize.

Measurements of the power spectrum from large-scale structure surveys have, to date, assumed an equal-time approximation, where the full cross-correlation power spectrum of the matter density field evaluated at different times (or distances) has been approximated either by the power spectrum at a fixed time or in an improved fashion, by a geometric mean $P(k;r_1,r_2)=[P(k;r_1)P(k;r_2){]}^{1/2}$. In this paper we investigate the expected impact of the geometric mean ansatz and present an application in assessing the impact on weak-gravitational-lensing cosmological parameter inference, using a perturbative unequal time correlator. As one might expect, we find that the impact of this assumption is greatest at large separations in redshift $\mathrm{\Delta }z\gtrsim 0.3$ where the change in the amplitude of the matter power spectrum can be as much as 10 percent for $k\gtrsim 5h{\mathrm{Mpc}}^{-1}$. However, of more concern is that the corrections for small separations, where the clustering is not close to zero, may not be negligibly small. In particular, we find that for a Euclid- or LSST-like weak lensing experiment, the assumption of equal-time correlators may result in biased predictions of the cosmic shear power spectrum, and that the impact is strongly dependent on the amplitude of the intrinsic alignment signal. To compute unequal-time correlations to sufficient accuracy will require advances in either perturbation theory to high $k$ modes or extensive use of simulations.