Calibration of the Advanced LIGO detectors is the quantification of the detectors’ response to gravitational waves. Gravitational waves incident on the detectors cause phase shifts in the interferometer laser light which are read out as intensity fluctuations at the detector output. Understanding this detector response to gravitational waves is crucial to producing accurate and precise gravitational wave strain data. Estimates of binary black hole and neutron star parameters and tests of general relativity require well-calibrated data, as miscalibrations will lead to biased results. We describe the method of producing calibration uncertainty estimates for both LIGO detectors in the first and second observing runs.

We evaluate the two-photon exchange correction to the elastic electron-proton scattering cross section within a dispersive framework. Besides the elastic contribution, we account for all $\pi N$ intermediate state contributions using the phenomenological MAID fit as an input. We develop a novel method for the analytical continuation of the two-photon exchange amplitudes into the unphysical region and generalize our previous work to the momentum transfer region $0.064{\mathrm{GeV}}^2\lesssim Q^2\lesssim 1{\mathrm{GeV}}^2$. We compare our results with recent OLYMPUS, CLAS and VEPP-3 data as well as with empirical fits and estimates in the forward angular region.

We demonstrate a new method of extracting parton distributions from lattice calculations. The starting idea is to treat the generic equal-time matrix element $\mathcal{M}(P{z}_3,z_3^2)$ as a function of the Ioffe time $\nu =P{z}_3$ and the distance $z_3$. The next step is to divide $\mathcal{M}(P{z}_3,z_3^2)$ by the rest-frame density $\mathcal{M}(0,z_3^2)$. Our lattice calculation shows a linear exponential $z_3$-dependence in the rest-frame function, expected from the $Z(z_3^2)$ factor generated by the gauge link. Still, we observe that the ratio $\mathcal{M}(P{z}_3,z_3^2)/\mathcal{M}(0,z_3^2)$ has a Gaussian-type behavior with respect to $z_3$ for 6 values of $P$ used in the calculation. This means that $Z(z_3^2)$ factor was canceled in the ratio. When plotted as a function of $\nu$ and $z_3$, the data are very close to $z_3$-independent functions. This phenomenon corresponds to factorization of the $x$- and $k_{\perp }$-dependence for the TMD $\mathcal{F}(x,k_{\perp }^2)$. For small $z_3\le 4a$, the residual $z_3$-dependence is explained by perturbative evolution, with ${\alpha }_s/\pi =0.1$.

Based on a chiral constituent quark model, we calculate the charge distributions of $d^{*}(2380)$. We consider the existence of two different interpretations of the $d^{*}$: a compact structure in the two-coupled-channel ($\mathrm{\Delta }\mathrm{\Delta }+CC$) approximation, and a resonant structure of $D_{12}\pi$. We calculate the charge distribution of the $d^{*}$ with a compact structure, and we also roughly estimate the charge distribution for a $D_{12}\pi$ structure on the same base. The result shows that there is a remarkable difference in the charge distributions of the two structural pictures. Therefore, we expect that future experiments may provide a clear signal for the $d^{*}$ structure.

We investigate exact nonstationary quantum states of vacuum toroidal black holes with a negative cosmological constant in arbitrary dimensions using the framework of throat quantization pioneered by Louko and Mäkelä for Schwarzschild black holes. The system is equivalent to a harmonic oscillator on the half line, in which the central singularity is resolved quantum mechanically by imposing suitable boundary conditions that preserve unitarity. We identify two suitable families of exact time-dependent wave functions with Dirichlet or Neumann boundary conditions at the location of the classical singularity. We find that for highly nonstationary states of large-mass black holes, quantum fluctuations are not negligible in one family, while they are greatly suppressed in the other. The latter, therefore, may provide candidates for describing the dynamics of semiclassical black holes.

We describe a quantum limit to the measurement of classical spacetimes. Specifically, we formulate a quantum Cramér-Rao lower bound for estimating the single parameter in any one-parameter family of spacetime metrics. We employ the locally covariant formulation of quantum field theory in curved spacetime, which allows for a manifestly background-independent derivation. The result is an uncertainty relation that applies to all globally hyperbolic spacetimes. Among other examples, we apply our method to the detection of gravitational waves with the electromagnetic field as a probe, as in laser-interferometric gravitational-wave detectors. Other applications are discussed, from terrestrial gravimetry to cosmology.

We employ a fully renormalized computation of the one loop contribution to the self-mass-squared of the conformally coupled (CC) scalar interacting with gravitons during inflation to study how inflationary produced gravitons affect the CC scalar evolution equation. The quantum corrected scalar mode functions turn out to get a secular growth effect, proportional to a logarithm of the scale factor at late times.

Three self-gravitating $SO(10)$ domain walls in five dimensions are obtained and their properties are analyzed. These non-Abelian domain walls interpolate between ${\mathrm{AdS}}_5$ spacetimes with different embedding of $SU(5)$ in $SO(10)$ and they can be distinguished, among other features, by the unbroken group on each wall, being either $SO(10)$, $SO(6)\otimes SU(2)\otimes U(1)/Z_2$ or $SU(4)\otimes SO(2)\otimes U(1)/Z_4$. We show that, unlike Minkowskian versions, the curved scenarios are perturbatively stable due to the gravitational capture of scalar fluctuations associated to the residual orthogonal subgroup in the core of the walls. These stabilizer modes are additional to the four-dimensional Nambu-Goldstone states found in two of the three gravitational scenarios.

One of the striking features of QED is that charged particles create a coherent cloud of photons. The resultant coherent state vectors of photons generate a nontrivial representation of the localized algebra of observables that do not support a representation of the Lorentz group: Lorentz symmetry is spontaneously broken. We show in particular that Lorentz boost generators diverge in this representation, a result shown also by Balachandran et al. [Eur. Phys. J. C 75, 89 (2015)] (see also the work by Balachandran et al. [Mod. Phys. Lett. A 28, 1350028 (2013)]. Localization of observables, for example in the Rindler wedge, uses Poincaré invariance in an essential way [Int. J. Geom. Methods Mod. Phys. 14, 1740008 (2017).]. Hence, in the presence of charged fields, the photon observables cannot be localized in the Rindler wedge. These observations may have a bearing on the black hole information loss paradox, as the physics in the exterior of the black hole has points of resemblance to that in the Rindler wedge.

We propose a new energy extraction mechanism from the rotational energy of a Kerr-Newman black hole by a gravitating massive photon field generated by electromagnetic and gravitational field coupling effects. Numerical studies show that this mechanism that depends on the black hole rotation parameter, $a$, shows a clear dependence on the black hole mass, $M$, and charge, $Q$, and can extract energies up to $10^{54}\text{erg}$ for a black hole of the solar mass size. With this mechanism we can set a lower bound on the coupling $\xi \sim {10}^{-38}$ between electromagnetic and gravitational fields that might be used to explain the hypothetical extremely high energy release, $>{10}^{53}\text{erg}$, suggested by the observations of some gamma-ray bursts in the controversial “energy crisis” problem if and when gamma-ray bursts seem not to show evidence for collimated emission.

The dilaton is a possible inflaton candidate following recent CMB data allowing a nonminimal coupling to the Ricci curvature scalar in the early Universe. In this paper, we introduce an approach that has seldom been used in the literature, namely dilaton inflation with non-local features. More concretely, employing non-local features expressed in [J. High Energy Phys. 04 (2007) 029], we study quadratic variations around a de Sitter geometry of an effective action with a nonlocal dilaton. The nonlocality refers to an infinite derivative kinetic term involving the operator $\mathcal{F}(\square )$. Algebraic roots of the characteristic equation $\mathcal{F}(z)=0$ play a crucial role in determining the properties of the theory. We subsequently study the cases when $\mathcal{F}(\square )$ has one real root and one complex root, from which we retrieve two concrete effective models of inflation. In the first case we retrieve a class of single field inflations with universal prediction of $n_s\sim 0.967$ with any value of the tensor to scalar ratio $r<0.1$ intrinsically controlled by the root of the characteristic equation. The second case involves a new class of two field conformally invariant models with a peculiar quadratic cross-product of scalar fields. In this latter case, we obtain Starobinsky-like inflation through a spontaneously broken conformal invariance. Furthermore, an uplifted minimum of the potential, which accounts for the vacuum energy after inflation is produced naturally through this mechanism intrinsically within our approach.

Ultrahigh-energy cosmic rays (UHECRs) can be accelerated by tidal disruption events of stars by black holes. We suggest a novel mechanism for UHECR acceleration wherein white dwarfs (WDs) are tidally compressed by intermediate-mass black holes (IMBHs), leading to their ignition and subsequent explosion as a supernova. Cosmic rays accelerated by the supernova may receive an energy boost when crossing the accretion-powered jet. The rate of encounters between WDs and IMBHs can be relatively high, as the number of IMBHs may be substantially augmented once account is taken of their likely presence in dwarf galaxies. Here we show that this kind of tidal disruption event naturally provides an intermediate composition for the observed UHECRs, and suggest that dwarf galaxies and globular clusters are suitable sites for particle acceleration to ultrahigh energies.

Scalar condensates with large expectation values can form in the early universe, for example, in theories with supersymmetry. The condensate can undergo fragmentation into Q-balls before decaying. If the Q-balls dominate the energy density for some period of time, statistical fluctuations in their number density can lead to formation of primordial black holes (PBH). In the case of supersymmetry the mass range is limited from above by $10^{23}\mathrm{g}$. For a general charged scalar field, this robust mechanism can generate black holes over a much broader mass range, including the black holes with masses of 1–100 solar masses, which is relevant for LIGO observations of gravitational waves. Topological defects can lead to formation of PBH in a similar fashion.

We reevaluate the predictions of inflation regarding primordial gravity waves, which should appear as $B$-modes in the cosmic microwave background (CMB), in light of the fact that the standard inflationary paradigm is unable to account for the transition from an initially symmetric state into a nonsymmetric outcome. We show that the incorporation of an element capable of explaining such a transition dramatically alters the prediction for the shape and size of the $B$-mode spectrum. In particular, we find that by adapting a realistic objective collapse model to the situation at hand, the $B$-mode spectrum becomes strongly suppressed with respect to the standard prediction. We conclude that the failure to detect $B$-modes in the CMB does not rule out the simplest inflationary models.

The Georgi-Machacek model is one of many beyond-Standard Model scenarios with an extended scalar sector that can group under the custodial $SU(2{)}_C$ symmetry. There are 5-plet, triplet, and singlet Higgs bosons under the classification of such symmetry in addition to the Standard Model Higgs boson. In this paper, we study the prospects for detecting the doubly-charged Higgs boson ($H_5^{\pm \pm }$) through the vector boson fusion production at the electron-proton colliders. We concentrate on our analysis through $\mu$-lepton pair production from a pair of same-sign W bosons decay. The $H_5^{\pm \pm }$ discovery potentials at the electron-proton colliders are presented.

We provide the first explicit calculation showing that parapositronium can decay into three photons. While this decay is forbidden within quantum electrodynamics because it violates charge conjugation symmetry, it proceeds through the weak interaction. We compute the charged weak boson contribution to the photon energy spectrum and the rate of this decay.