In previous work, two of us constructed the holographic dual of a single Einstein-Podolsky-Rosen (EPR) pair in maximally supersymmetric Yang-Mills theory. Here we extend that work in two directions. First, we use a Randall-Sundrum brane to couple the entangled pair to dynamical gravity. Second, we consider the entangled pair in the background of a black brane with the particles on opposite sides of the horizon, turning the EPR pair into a Hawking pair. Along the way, we use the Hawking pair to exhibit the confinement of the super Yang-Mills theory on a black brane background. We give general arguments that $\mathrm{ER}=\mathrm{EPR}$ should be understood as a duality between two equivalent descriptions of the same physical reality.

There are both the black hole horizon and the cosmological horizon for the charged topological dilaton de Sitter spacetime. The thermodynamic quantities on both horizons satisfy the first law of black hole thermodynamics. Because all of these thermodynamic quantities depend on the mass $M$, the electric charge $Q$, and the cosmological constant $l$, the two horizons are not independent. Considering the connection between the black hole horizon and the cosmological horizon, we derive the effective thermodynamic quantities of the ($n+1$)-dimensional charged topological dilaton de Sitter spacetime. We find that the charged topological dilaton black hole in de Sitter spacetime has a similar phase transition and critical behavior to that in anti–de Sitter spacetime.

Here we show that Eddington’s pure affine gravity, when extended with Riemann curvature, leads to gravitational field equations that incorporate matter. This Riemanned Eddington gravity outfits a setup in which matter gravitates normally with Newton’s constant but vacuum gravitates differently with an independent gravitational constant. This novel setup enables degravitation of the vacuum to observed level not by any fine-tuning but by a large hierarchy between its gravitational constant and its energy density. Remarkably, degravitation of the cosmological constant is local, causal and natural yet only empirical because the requisite degravitation condition is not predicted by the theory.

We study the dynamical properties and space distribution of dark energy in the weak and strong gravitational fields caused by inhomogeneities of matter in the static world of galaxies and clusters. We show that the dark energy in the weak gravitational fields of matter density perturbations can condense or dilute, but amplitudes of its perturbations remain very small on all scales. We illustrate also how the “accretion” of the phantom dark energy onto the matter overdensity forms the dark energy underdensity. We analyze the behavior of dark energy in the gravitational fields of stars and black holes with the Schwarzschild metric. It is shown that, in the case of stars, the static solution of the differential equations for energy-momentum conservation exists and describes the distribution of density of dark energy inside and outside of a star. We have found that for stars and galaxies its value differs slightly from the average and is a bit higher for the quintessential scalar field as dark energy and a bit lower for the phantom one. The difference grows with the decrease of the effective sound speed of dark energy and is large in the neighborhood of neutron stars. We obtain and analyze also the solutions of equations that describe the stationary accretion of the dark energy as a test component onto the Schwarzschild black hole. It is shown that the rate of change of mass of the dark energy is positive in the case of quintessential dark energy and is negative in the case of the phantom one.

The number of ultrahigh energy events at IceCube is estimated, for the first time, taking into account nonlinear QCD effects in the neutrino-hadron cross section. We assume that the extragalactic neutrino flux is given by ${\mathrm{\Phi }}_{\nu }(E_{\nu })={\mathrm{\Phi }}_0{E}_{\nu }^{-2}$ and estimate the neutrino-hadron cross section using the dipole approach and a phenomenological model for the dipole-hadron cross section based on nonlinear QCD dynamics. We demonstrate that the nonlinear prediction is able to describe the current IceCube data and that the magnitude of the nonlinear effects is larger than 20% for visible energies of order of 2 PeV and increases with the neutrino energy. Our main conclusion is that the nonlinear QCD effects are non-negligible and should be taken into account in the analysis of the number of ultrahigh energy events.

As a first numerical application of the light-front coupled-cluster (LFCC) method, we consider the odd-parity massive eigenstate of ${\varphi }_{1+1}^4$ theory. The eigenstate is built as a Fock-state expansion in light-front quantization, where wave functions appear as coefficients of the Fock states. A standard Fock-space truncation would then yield a finite set of linear equations for a finite number of wave functions. The LFCC method replaces Fock-space truncation with a more sophisticated truncation, one which reduces the eigenvalue problem to a finite set of nonlinear equations without any restriction on Fock space. We compare our results with those obtained with a Fock-space truncation that yields the same number of equations.

The correlation between the invisible Higgs branching ratio ($B_h^{\text{inv}}$) versus dark matter (DM) direct detection cross section (${\sigma }_p^{\mathrm{SI}}$) in Higgs portal singlet fermion DM (SFDM) or vector DM (VDM) models is usually presented in the effective field theory (EFT) framework. In this paper, we derive the explicit expressions for this correlation within UV completions of SFDM and VDM models with Higgs portals, and we discuss the limitations of the EFT approach. We show that there are at least two additional hidden parameters in ${\sigma }_p^{\mathrm{SI}}$ in the UV completions: the singletlike scalar mass $m_2$ and its mixing angle $\alpha$ with the SM Higgs boson ($h$). In particular, if the singletlike scalar is lighter than the SM Higgs boson ($m_2<m_h\cos \alpha /\sqrt{1+{\cos }^2\alpha }$), the collider bound becomes weaker than the one based on EFT.

The Balitskii-Fadin-Kuraev-Lipatov multi-Pomeron model of Levin and Rezaeian, with extension to the gluon saturation region, is applied to long-range pseudorapidity correlations on relative azimuth for low-momentum final-state hadrons produced in $\sqrt{s}=200\mathrm{GeV}$ and 7 TeV $p+p$ collisions. The multi-Pomeron exchange probabilities in the model were estimated by fitting the minimum-bias $p+p$ multiplicity frequency distributions. The multi-Pomeron model prediction for the amplitude of the minimum-bias average quadrupole correlation, proportional to $\cos 2({\varphi }_1-{\varphi }_2)$, is consistent with the 200 GeV data when theoretically expected gluon saturation momentum scales are used. Correlation predictions for the high-multiplicity 7 TeV $p+p$ collision data are also consistent with the long-range pseudorapidity correlations at small relative azimuth observed in the data. The results presented here show that the present application of a multiple-parton-shower gluon interference mechanism for generating the long-range pseudorapidity, azimuthal quadrupole correlation is not excluded by the data.

We investigate the effect of a finite volume on the critical behavior of the theory of the strong interaction, Quantum Chromodynamics (QCD), by means of a quark-meson model for $N_{\mathrm{f}}=2$ quark flavors. In particular, we analyze the effect of a finite volume on the location of the critical point in the phase diagram existing in our model. In our analysis, we take into account the effect of long-range fluctuations with the aid of renormalization group techniques. We find that these quantum and thermal fluctuations, absent in mean-field studies, play an import role for the dynamics in a finite volume. We show that the critical point is shifted towards smaller temperatures and larger values of the quark chemical potential if the volume size is decreased. This behavior persists for antiperiodic as well as periodic boundary conditions for the quark fields as used in many lattice QCD simulations.

We discuss how the ${\mathrm{UN}}^2\mathrm{LOPS}$ scheme for matching next-to-next-to-leading order (NNLO) calculations to parton showers can be applied to processes with large higher-order perturbative QCD corrections. We focus on Higgs-boson production through gluon fusion as an example. We also present an NNLO fixed-order event generator for this reaction.

We discuss the nature of the ${\chi }_b(3P)$ and $X(3872)$ mesons. Are the ${\chi }_b(3P)$’s standard $b\overline{b}$ mesons or $b\overline{b}$ states with a significative continuum component? Is the $X(3872)$ a $c\overline{c}$ state with continuum coupling effects or a meson-meson molecule? To do that, we compare quark model and unquenched quark model results for the mass barycenter and splittings of the ${\chi }_b(3P)$ multiplet. Future and more precise experimental results will discriminate between the two interpretations. In the case of the $X(3872)$, we interpret it as a $c\overline{c}$ core plus higher Fock components due to the coupling to the meson-meson continuum, and thus we think that it is compatible with the meson ${\chi }_{c1}(2P)$, with $J^{PC}=1^{++}$. The $J^{PC}=1^{++}$ quantum numbers are in agreement with the experimental results found by the LHCb collaboration. In our view, the $X(3872)$’s mass is lower than the quark model’s predictions because of self-energy shifts. We also provide an estimation of the open charm/bottom strong decay modes of the $X(3872)$ and ${\chi }_b(3P)$ mesons, such as $X(3872)\to D{\overline{D}}^{*}$ and ${\chi }_{b2}(3P)\to B\overline{B}$, and radiative transitions.

Coy dark matter removes the tension between the traditional WIMP paradigm of dark matter and the latest exclusion bounds from direct detection experiments. In this paper we present a leptophilic coy dark matter model that, on top of explaining the spatially extended 1–5 GeV $\gamma$-ray excess detected at the galactic center, reconciles the measured anomalous magnetic moment of muon with the corresponding standard model prediction. The annihilation channel of dark matter is $\chi \chi \to \tau \overline{\tau }$ with the dark matter mass $m_{\chi }=9.43{(}_{-0.52}^{+.063}\text{stat})(\pm 1.2\text{sys})\mathrm{GeV}$ given by best-fit of the $\gamma$-ray excess. Fitting the measured anomalous magnetic moment of the muon requires instead a pseudoscalar mediator with a minimal mass $m_a={12}_{-3}^{+7}\mathrm{GeV}$.

Maximally supersymmetric Yang–Mills theory in four dimensions can be formulated on a space-time lattice while exactly preserving a single supersymmetry. Here we explore in detail this lattice theory, paying particular attention to its strongly coupled regime. Targeting a theory with gauge group $\mathrm{SU}(N)$, the lattice formulation is naturally described in terms of gauge group $\mathrm{U}(N)$. Although the U(1) degrees of freedom decouple in the continuum limit we show that these degrees of freedom lead to unwanted lattice artifacts at strong coupling. We demonstrate that these lattice artifacts can be removed, leaving behind a lattice formulation based on the $\mathrm{SU}(N)$ gauge group with the expected apparently conformal behavior at both weak and strong coupling.

In view of the obstacles encountered in any attempts to solve the Minkowski-space Bethe-Salpeter equation for bound states of two fermions, we study the possibility to model the bound-state features, at least at a qualitative level, by a Schrödinger description. Such a nonrelativistic potential model can be constructed by applying, to any given Bethe-Salpeter spectral data, “geometric spectral inversion” in its recently extended form, which tolerates also singular potentials. This leads to the adaptation of explicit models that provide an overview accounting for the Bethe-Salpeter formalism’s complexities.

In this paper, we describe a hybrid-extended Kalman filter algorithm to synchronize the clocks and to precisely determine the interspacecraft distances for space-based gravitational wave detectors, such as (e)LISA. According to the simulation, the algorithm has significantly improved the ranging accuracy and synchronized the clocks, making the phase-meter raw measurements qualified for time-delay interferometry algorithms.

We study cosmological perturbations in the framework of loop quantum cosmology, using a hybrid quantization approach and Mukhanov–Sasaki variables. The formulation in terms of these gauge invariants allows one to clarify the independence of the results on choices of gauge and facilitates the comparison with other approaches proposed to deal with cosmological perturbations in the context of loop quantum theory. A kind of Born–Oppenheimer ansatz is employed to extract the dynamics of the inhomogeneous perturbations, separating them from the degrees of freedom of the Friedmann–Robertson–Walker geometry. With this ansatz, we derive an approximate Schrödinger equation for the cosmological perturbations and study its range of validity. We also prove that, with an alternate factor ordering, the dynamics deduced for the perturbations is similar to the one found in the so-called dressed metric approach, apart from a possible scaling of the matter field in order to preserve its unitary evolution in the regime of quantum field theory in a curved background and some quantization prescription issues. Finally, we obtain the effective equations that are naturally associated with the Mukhanov–Sasaki variables, both with and without introducing the Born–Oppenheimer ansatz, and with the different factor orderings that we have studied.

Coupling dark energy and dark matter through an effective fluid description is a very common procedure in cosmology; however, it always remains in comoving coordinates in the special FLRW space. We construct a consistent, general, and covariant formulation, where the interaction is a natural implication of the imperfectness of the fluids. This imperfectness makes difficult the final step towards a robust formulation of interacting fluids, namely the construction of a Lagrangian whose variation would give rise to the interacting equations. Nevertheless, we present a formal solution to this problem for a single fluid, through the introduction of an effective metric.

We will study the cosmological evolutions of a Weyl-invariant de Rham, Gabadadze, and Tolley (dRGT) massive gravity theory with a general fiducial metric. In the unitary gauge, this model is equivalent to a massive gauge field coupled to the dRGT massive gravity model. The massive gravity terms will serve as an effective cosmological constant for all metric spaces if the fiducial metric is treated as an auxiliary field. A further discussion will also be addressed on the bimetric theory. In particular, we will discuss the role played by the Weyl vector boson in Bianchi type I expanding space.

We estimated the sensitivity of the upcoming advanced ground-based gravitational-wave observatories (the LIGO, Virgo, and KAGRA interferometers) to coalescing intermediate mass black hole binaries (IMBHB). We added waveforms modeling the gravitational radiation emitted by IMBHBs to simulated data from detectors and searched for the injected signals with the coherent WaveBurst algorithm. The tested parameter space of the binaries covers nonspinning IMBHBs with source-frame total masses between 50 and $1050{\mathrm{M}}_{\odot }$ and mass ratios between $1/6$ and 1. We found that advanced detectors could be sensitive to these systems up to a range of a few Gpc. A theoretical model was adopted to estimate the expected observation rates, yielding up to a few tens of events per year. Thus, our results indicate that advanced detectors will have a reasonable chance to collect the first direct evidence for intermediate mass black holes and to open a new, intriguing channel for probing the Universe over cosmological scales.

We obtain stronger laboratory constraints on the coupling constants of axion-like particles to nucleons from measurements of the normal and lateral Casimir forces between sinusoidally corrugated surfaces of a sphere and a plate. For this purpose, the normal and lateral additional forces arising in the experimental configurations due to the two-axion exchange between protons and neutrons are calculated. Our constraints following from measurements of the normal and lateral Casimir forces are stronger than the laboratory constraints reported so far for masses of axion-like particles larger than 11 and 8 eV, respectively. A comparison between various laboratory constraints on the coupling constants of axion-like particles to nucleons obtained from the magnetometer measurements, Eötvos- and Cavendish-type experiments, and from the Casimir effect is performed over the wide range of masses of axion-like particles from $10^{-10}$ to 20 eV.