We derive the weak field limit of scalar-Gauss-Bonnet theory and place novel bounds on the parameter space using terrestrial and space-based experiments. In order to analyze the theory in the context of a wide range of experiments, we compute the deviations from Einstein gravity around source masses with planar, cylindrical, and spherical symmetry. We find a correction to the Newtonian potential around spherical and cylindrical sources that can be larger than parametrized post-Newtonian corrections sufficiently close to the source. We use this to improve on laboratory constraints on the scalar-Gauss-Bonnet coupling parameter $\mathrm{\Lambda }$ by a factor of 3. Present laboratory and Solar System bounds reported here are superseded by tests deriving from black holes.

This paper investigates the coplanar and circular three-body problem in the parametrized post-Newtonian (PPN) formalism, for which we focus on a class of fully conservative theories characterized by the Eddington-Robertson parameters $\beta$ and $\gamma$. It is shown that there can still exist a collinear equilibrium configuration and a triangular one, each of which is a generalization of the post-Newtonian equilibrium configuration in general relativity. The collinear configuration can exist for arbitrary mass ratio, $\beta$, and $\gamma$. On the other hand, the PPN triangular configuration depends on the nonlinearity parameter $\beta$ but not on $\gamma$. For any value of $\beta$, the equilateral configuration is possible, if and only if three finite masses are equal or two test masses orbit around one finite mass. For general mass cases, the PPN triangle is not equilateral as in the post-Newtonian case. It is shown also that the PPN displacements from the Lagrange points in the Newtonian gravity $L_1$, $L_2$, and $L_3$ depend on $\beta$ and $\gamma$, whereas those to $L_4$ and $L_5$ rely only on $\beta$.

In this paper, we revisit the null boundary gravitational charge in the Newman-Penrose formalism with special emphasis on the charges from local Lorentz transformations. We find that there is one more charge derived from the local Lorentz transformation, and the new charge is purely from the Holst term. This reveals a remarkable fact that trivial terms which do not change classical equations of motion can not only affect the boundary degrees of freedom through their contributions to the boundary charges but also have their own rights to create new boundary degrees of freedom.

Compensated isocurvature perturbations (CIPs) are relative density perturbations in which a baryon-density fluctuation is accompanied by a dark matter density fluctuation such that the total-matter density is unperturbed. These fluctuations can be produced primordially if multiple fields are present during inflation, and therefore they can be used to differentiate between different models for the early Universe. Kinetic Sunyaev-Zeldovich tomography allows for the reconstruction of the radial-velocity field of matter as a function of redshift. This technique can be used to reconstruct the total-matter-overdensity field, independent of the galaxy-density field obtained from large-scale galaxy surveys. We leverage the ability to measure the galaxy, and matter, overdensity fields independently to construct a minimum-variance estimator for the primordial compensated isocurvature perturbation (CIP) amplitude, based on a mode-by-mode comparison of the two measurements. We forecast that a configuration corresponding to CMB-S4 and VRO will be able to detect (at $2\sigma$) a CIP amplitude $A$ (for a scale-invariant power spectrum) as small as $A\simeq 5\times {10}^{-9}$. Similarly, a configuration corresponding to SO and DESI will be sensitive to a CIP amplitude $A\simeq 1\times {10}^{-7}$. These values are to be compared to current constraints $A\le \mathcal{O}(0.01)$.

The James Webb Space Telescope has detected surprisingly luminous early galaxies that indicate a tension with the $\mathrm{\Lambda }$ cold dark matter. Motivated by scenarios including axion miniclusters or primordial black holes, we consider power-law modifications of the matter power spectrum. We show that the tension could be resolved if dark matter consists of $2\times {10}^{-18}\mathrm{eV}$ axions or if a fraction $f_{\mathrm{PBH}}>0.005$ of dark matter is composed of compact heavy $4\times {10}^6{M}_{\odot }(f_{\mathrm{PBH}}/0.005{)}^{-1}$ structures such as primordial black hole clusters. However, in both cases, the star formation efficiency needs to be significantly enhanced.

Observations of the Milky Way at TeV–PeV energies reveal a bright diffuse flux of hadronic cosmic rays and also bright point sources of gamma rays. If the gamma-ray sources are hadronic cosmic-ray accelerators, then they must also be neutrino sources. However, no neutrino sources have been detected. Where are they? We introduce a new population-based approach to probe Milky Way hadronic PeVatrons, demanding consistency between diffuse and point-source PeV-range data on cosmic rays, gamma rays, and neutrinos. For the PeVatrons, two extreme scenarios are allowed: (1) the hadronic cosmic-ray accelerators and the gamma-ray sources are the same objects, so that bright neutrino sources exist and improved telescopes can detect them, versus (2) the hadronic cosmic-ray accelerators and the gamma-ray sources are distinct, so that there are no detectable neutrino sources. The latter case is possible if hadronic accelerators have sufficiently thin column densities. We quantify present constraints and future prospects, showing how to reveal the nature of the hadronic PeVatrons.

KAGRA is the first kilometer scale gravitational wave detector to be constructed underground and employ cryogenics to cool down its test masses. While the underground location provides a quiet site with low seismic noise, the cooling infrastructure is known to generate large mechanical vibrations due to cryocooler operation and structural resonances of the cryostat. As cooling system components are relatively heavy and in close proximity to the test masses, oscillation of gravity force induced by their vibration, so-called Newtonian noise, could contaminate the detector sensitivity. In this paper, we use the results from vibration analysis of the KAGRA cryostat to estimate cooling system Newtonian noise in the 1–100 Hz frequency band. Our calculations show that, while this noise does not limit the current detector sensitivity or inspiral range, it will be an issue in the future when KAGRA improves its sensitivity. We conclude that KAGRA may need to implement Wiener filters to subtract this noise in the future.

We compute the vacuum polarization energies (VPEs) of solitons in a self-dual impurity model in which the soliton profiles take the shape of a separated kink-antikink pair. Classically the soliton energies are invariant under the change of a continuous parameter that can be interpreted as the kink-antikink separation. This is not the case for the VPEs so that quantum effects decide on the energetically most favorable separation. The considered configurations are classically stable so that its quantum fluctuations have only real frequency eigenvalues. Hence, in contrast to the kink-antikink configuration in the ${\varphi }^4$ model, the VPE is well defined for any value of the separation and we gain insight into the quantum corrections to the kink-antikink potential.

We investigate the possibility to identify the intrinsic spin of exotic charged particles at a future $e^{+}{e}^{-}$ collider in the $l^{\pm }+2j+{\cancel{E}}_T$ final state. We choose the inert doublet model (IDM) and minimal supersymmetric standard model (MSSM) as examples for the new physics models with scalar and fermionic exotic charged particles, respectively. The signal arises when these exotic charged particles are pair produced and then decay to a $W^{\pm }$ boson and the lightest neutral stable particle in the new physics model. We choose four benchmarks for the mass parameters which give significant deviation from the dominant standard model (SM) $W^{+}{W}^{-}$ background. We find that an asymmetry in the cosine of the scattering angle ($\cos \theta$) of one of the $W$ bosons reconstructed from $jj$ pair as well as the charged lepton have the potential to identify the MSSM and IDM signal over SM with longitudinally polarized initial beams. A more robust distinction is seen in the shape of the azimuthal angle distribution of the $W$ boson and charged lepton, which can identify and distinguish the IDM signal from MSSM further if the initial beams are transversely polarized.

The interaction of defects can lead to a phenomenon of erasure. During this process, a lower-dimensional object gets absorbed and dissolved by a higher-dimensional one. The phenomenon is very general and has a wide range of implications, both cosmological and fundamental. In particular, all types of strings, such as cosmic strings, QCD flux tubes, or fundamental strings, get erased when encountering a defect, either solitonic or a D-brane that deconfines their fluxes. This leads to a novel mechanism of cosmic string breakup, accompanied by gravitational and electromagnetic radiations. The arguments based on loss of coherence and the entropy count suggest that the erasure probability is very close to one, and strings never make it through the deconfining layer. We confirm this by a numerical simulation of the system, which effectively captures the essence of the phenomenon: a $2+1$-dimensional problem of interaction between a Nielsen-Olesen vortex of a $U(1)$ Higgs model and a domain wall, inside which the $U(1)$ gauge group is un-Higgsed and the magnetic flux is deconfined. In accordance with the entropy argument, in our simulation, the vortex never makes it across the wall.

Working in the nonrelativistic-QCD factorization framework at next-to-leading order in ${\alpha }_s$, we fit the relevant color octet long-distance matrix elements of the $\psi (2S)$ meson, $⟨{\mathcal{O}}^{\psi (2S)}({{}^{1}S}_0^{[8]})⟩$, $⟨{\mathcal{O}}^{\psi (2S)}({{}^{3}S}_1^{[8]})⟩$, and $⟨{\mathcal{O}}^{\psi (2S)}({{}^{3}P}_0^{[8]})⟩$, to 1001 data points of upolarized and polarized $\psi (2S)$ inclusive hadroproduction. We do four different fits, with filters on polarization and low to middle transverse momentum $p_T$. We find that a successful description of the data is only possible with a large low-$p_T$ cut. Our results are one order of magnitude more precise than previous determinations of these color octet long-distance matrix elements.

I argue that in large-$N$ supersymmetric QCD infrared renormalons are absent in the conformal window, there is no need in conspiracy between the coefficient functions and the vacuum expectation values of at least some gluon operators—no factorials appear in the former and the latter vanish. Based on this conclusion, I conjecture that in supersymmetric gluodynamics (supersymmetric Yang-Mills theory without matter) at least the leading renormalon ambiguity disappears, which would be consistent with the fact that the gluon condensate vanishes in this theory, $⟨G_{\mu \nu }^a{G}^{\mu \nu a}⟩=0$.

Two entangled two-level Unruh-DeWitt detectors, which are in rest, spontaneously lose entanglement when at least one of them is not isolated from the environment quantum fields. For eternal interaction between the detectors and environment, the spontaneous emission from the detectors’ exited states and vacuum fluctuations of field influence this negative effect. Consequently, it suggests that two entangled qubits become less communicated during their free fall towards the black hole horizon.

With certain nonminimal coupling between a massless scalar field and the Gauss-Bonnet curvature invariant in the extended scalar-tensor-Gauss-Bonnet (ESTGB) field theory, tachyonic instability of the Kerr-Newman (KN) black hole is promoted. Critical spin and charge for the onset of the spontaneous scalarization phenomenon for the KN black hole are calculated in the infinitely large coupling limit. Then the analytical formula for the coupling-strength-dependent critical existence line is obtained for the black-hole-scalar-field configuration in a finite large coupling regime. Moreover, numerical methods are used to perform threshold curves that are boundaries between bald KN black holes and their hairy counterparts. Intriguingly, we get to know the KN black hole can be scalarized in the vanishing spin limit in ESTGB theory.

Johnson [Phys. Rev. D 98, 026008 (2018)] has shown that in the vicinity of a critical point the efficiency of a black hole heat engine can approach the Carnot efficiency while maintaining finite power. We characterize and extend this result in several ways, and we show how the rate of approach to the Carnot efficiency is governed by the critical exponents. We apply these results to several classes of black holes to illustrate their validity. Odd-order Lovelock black holes are known to have isolated critical points for which the critical exponents differ from the mean field theory values, providing a nontrivial test of the results. In this case, our results indicate the impossibility of even-order Lovelock black holes with isolated critical points in this class: their existence would constitute a violation of the second law of thermodynamics.

As is well known, in order to generate magnetic fields of observed amplitudes during inflation, the conformal invariance of the electromagnetic field has to be broken by coupling it either to the inflaton or to the scalar curvature. Couplings to scalar curvature pose certain challenges even in slow roll inflation and it seems desirable to consider couplings to the inflaton. It can be shown that, in slow roll inflation, to generate nearly scale invariant magnetic fields of adequate strengths, the nonconformal coupling to the inflaton has to be chosen specifically depending on the inflationary model at hand. In a recent work, we had found that, when there arise sharp departures from slow roll inflation leading to strong features in the scalar power spectra, there inevitably arise sharp features in the spectra of the electromagnetic fields, unless the nonconformal coupling functions are extremely fine tuned. In particular, we had found that, if there occurs an epoch of ultra slow roll inflation (that is often required either to lower scalar power on large scales or to enhance power on small scales), then the strength of the magnetic field over large scales can be severely suppressed. In this work, we examine whether these challenges can be circumvented in models of inflation involving two fields. We show that the presence of the additional scalar field allows us to construct coupling functions that lead to magnetic fields of required strengths even when there arise intermediate epochs of ultra slow roll inflation. However, we find that the features in the spectra of the magnetic fields that are induced due to the departures from slow roll inflation cannot be completely ironed out. We make use of the code magcamb to calculate the effects of the magnetic fields on the anisotropies in the cosmic microwave background and investigate if the spectra with features are broadly consistent with the current constraints.

The kinematics of the three-body decay, with a modified energy-momentum relation of the particles due to a violation of Lorentz invariance, is presented in detail in the collinear approximation. The results are applied to the decay of superluminal neutrinos producing an electron-positron or a neutrino-antineutrino pair. Explicit expressions for the energy distributions, required for a study of the cascade of neutrinos produced in the propagation of superluminal neutrinos, are derived.

We give a detailed account of the theory of position space renormalization using graphical functions in the case of dimensionally regularized ${\varphi }^4$ theory in four dimensions. In this theory we calculate the beta function, the mass gamma function, and the self-energy to seven loops in the minimal subtraction scheme. The anomalous dimension $\gamma$ is calculated to loop order eight. When possible, we generalize to even dimensions $\ge 4$ with particular focus on ${\varphi }^3$ theory in six dimensions. In this theory we calculate the anomalous dimension $\gamma$ to loop order six.

We study the thermal properties of quantum field theories (QFT) with three-leg interaction vertices $g{\phi }^3$ and $gS{\phi }^2$ ($\phi$ and $S$ being scalar fields), which constitute the relativistic counterpart of the Yukawa potential. We follow a nonperturbative unitarized one-loop resummed technique for which the theory is unitary and well defined for a large range of values of the coupling constant $g$. Using the partial wave decomposition of two-body scattering we calculate the phase shifts, whose derivatives are used to infer the pressure of the system at nonzero temperature by using the so-called phase shift formalism. A $\phi \phi$ bound state is formed when the coupling $g$ is larger than a certain critical value. As the main outcomes of this work, we estimate the influence of particle interaction on the pressure (both without and with the bound state), and we demonstrate that the latter is always continuous as a function of the coupling constant $g$ (no sudden jumps occur when the bound state forms), and we show that the contribution of the bound state to the pressure does not count as one state in the thermal gas, since a cancellation with the residual $\phi \phi$ interaction occurs. The amount of this cancellation depends on the details of the model and its parameters and a variety of possible scenarios is presented. We also show how the overall effect of the interaction, including eventual resonances and bound states, can be formally described by a unique expression that makes use of the phase shift continued below the threshold.