Anti-de Sitter black holes exhibit van der Waals-type phase transition. In the extended phase-space formalism, the critical exponents for any spacetime metric are identical to the standard ones. Motivated by this fact, we give a general expression for the Helmholtz free energy near the critical point, which correctly reproduces these exponents. The idea is similar to the Landau model, which gives a phenomenological description of the usual second-order phase transition. Here, two main inputs are taken into account for the analysis: (a) black holes should have van der Waals-like isotherms, and (b) free energy can be expressed solely as a function of thermodynamic volume and horizon temperature. Resulting analysis shows that the form of Helmholtz free energy correctly encapsulates the features of the Landau function. We also discuss the isolated critical point accompanied by nonstandard values of critical exponents. The whole formalism is then extended to two other criticalities, namely, $Y-X$ and $T-S$ (based on the standard; i.e., nonextended phase space), where $X$ and $Y$ are generalized force and displacement, whereas $T$ and $S$ are the horizon temperature and entropy. We observe that in the former case Gibbs free energy plays the role of Landau function, whereas in the later case, that role is played by the internal energy (here, it is the black hole mass). Our analysis shows that, although the existence of a van der Waals phase transition depends on the explicit form of the black hole metric, the values of the critical exponents are universal in nature.

In this paper, we study the deflection of light by a class of charged wormholes within the context of the Einstein-Maxwell-dilaton theory. The primordial wormholes are predicted to exist in the early universe, where inflation is driven by the dilaton field. We perform our analysis through optical geometry using the Gibbons-Werner method (GW) by adopting the Gauss-Bonnet theorem and the standard geodesics approach. We report an interesting result for the deflection angle in leading-order terms—namely, the deflection angle increases due to the electric charge $Q$ and the magnetic charge $P$, whereas it decreases due to the dilaton charge $\mathrm{\Sigma }$. Finally, we confirm our findings by means of geodesics equations. Our computations show that the GW method gives an exact result in leading-order terms.

Continuum spectrum from black hole accretion disc holds enormous information regarding the strong gravity regime around the black hole and hence about the nature of gravitational interaction in extreme situations. Since in such strong gravity regime the dynamics of gravity should be modified from the Einstein-Hilbert one, its effect should be imprinted on the continuum spectrum originating from the black hole accretion. To explore the effects of these alternative theories on the black hole continuum spectrum in an explicit manner, we have discussed three alternative gravitational models having their origin in three distinct paradigms—(a) higher dimensions, (b) higher curvature gravity, and (c) generalized Horndeski theories. All of them can have signatures sculptured on the black hole continuum spectrum, distinct from the standard general relativistic scenario. Interestingly all these models exhibit black hole solutions with tidal charge parameter which in these alternative gravity scenarios can become negative, in sharp contrast with the Reissner-Nordström black hole. Using the observational data of optical luminosity for eighty Palomer Green quasars we have illustrated that the difference between the theoretical estimates and the observational results gets minimized for negative values of the tidal charge parameter. As a quantitative estimate of this result we concentrate on several error estimators, including reduced ${\chi }^2$, Nash-Sutcliffe efficiency, index of agreement etc. Remarkably, all of them indicates a negative value of the tidal charge parameter, signaling the possibility of higher dimensions as well as scalar charge at play in those high gravity regimes.

The observed dipole anisotropy of the cosmic microwave background (CMB) temperature is much larger than the fluctuations observed on smaller scales, and it is dominated by the kinematic contribution from the Doppler boosting of the monopole due to our motion with respect to the CMB rest frame. In addition to this kinematic component, there is expected to be an intrinsic contribution with an amplitude about two orders of magnitude smaller. Here we explore a method whereby the intrinsic CMB dipole can be reconstructed through observation of temperature fluctuations on small scales that result from gravitational lensing. Though the experimental requirements pose practical challenges, we show that one can, in principle, achieve a cosmic variance limited measurement of the primary dipole using the reconstruction method we describe. Since the primary CMB dipole is sensitive to the largest observable scales, such a measurement would have a number of interesting applications for early universe physics, including testing large-scale anomalies, extending the lever-arm for measuring local non-Gaussianity, and constraining isocurvature fluctuations on superhorizon scales.

We study the cosmological particle creation in the tachyon inflation based on the D-brane dynamics in the Randall-Sundrum (RSII) model extended to include matter in the bulk. The presence of matter modifies the warp factor which results in two effects: a modification of the RSII cosmology and a modification of the tachyon potential. Besides, a string theory D-brane supports among other fields a U(1) gauge field reflecting open strings attached to the brane. We demonstrate how the interaction of the tachyon with the U(1) gauge field drives cosmological creation of massless particles and estimate the resulting reheating at the end of inflation.

Angular momentum plays very important roles in the formation of primordial black holes in the matter-dominated phase of the Universe if it lasts sufficiently long. In fact, most collapsing masses are bounced back due to centrifugal force, since angular momentum significantly grows before collapse. For masses with $q\le q_c\simeq 2.4{\mathcal{I}}^{1/3}{\sigma }_H^{1/3}$, where $q$ is a nondimensional initial quadrupole moment parameter, ${\sigma }_H$ is the density fluctuation at horizon entry $t=t_H$, and $\mathcal{I}$ is a parameter of the order of unity, angular momentum gives a suppression factor $\sim \exp (-0.15{\mathcal{I}}^{4/3}{\sigma }_H^{-2/3})$ to the production rate. As for masses with $q>q_c$, the suppression factor is even stronger as $\sim \exp (-0.0046q^4/{\sigma }_H^2)$. We derive the spin distribution of primordial black holes and find that most of the primordial black holes are rapidly rotating near the extreme value $a_{*}=1$, where $a_{*}$ is the nondimensional Kerr parameter at their formation. The smaller ${\sigma }_H$ is, the stronger the tendency towards the extreme rotation. Combining this result with the effect of anisotropy, we numerically and semianalytically estimate the production rate ${\beta }_0$ of primordial black holes. Then we find that ${\beta }_0\simeq 1.9\times {10}^{-6}{f}_q(q_c){\mathcal{I}}^6{\sigma }_H^2\exp (-0.15{\mathcal{I}}^{4/3}{\sigma }_H^{-2/3})$ for ${\sigma }_H\lesssim 0.005$, while ${\beta }_0\simeq 0.05556{\sigma }_H^5$ for $0.005\lesssim {\sigma }_H\lesssim 0.2$, where $f_q(q_c)$ is the fraction of masses whose $q$ is smaller than $q_c$ and we assume $f_q(q_c)$ is not too small. We argue that matter domination significantly enhances the production of primordial black holes despite the suppression factor. If the end time $t_{\mathrm{end}}$ of the matter-dominated phase satisfies $t_{\mathrm{end}}\lesssim (0.4\mathcal{I}{\sigma }_H{)}^{-1}{t}_H$, the effect of the finite duration significantly suppresses primordial black hole formation and weakens the tendency towards large spins.

In an $SU(3{)}_c\times SU(2{)}_L\times SU(2{)}_R\times U(1{)}_{B-L}$ left-right symmetric framework, we present a new leptogenesis scenario parametrized by the Dirac neutrino mass matrix. Benefiting from the parity symmetry motivated to solve the strong $CP$ problem, the dimensionless couplings of the mirror fields are identified with those of the ordinary fields. In particular, the mirror Dirac neutrinos have a heavy mass matrix proportional to the light mass matrix of the ordinary Dirac neutrinos. Through the $SU(2{)}_R$ gauge interactions, the mirror neutrinos can decay to generate a lepton asymmetry in the mirror muons and an opposite lepton asymmetry in the mirror electrons. Before the $SU(2{)}_L$ sphaleron processes stop working, the mirror muons can efficiently decay into the ordinary right-handed leptons with a dark matter scalar, and hence the mirror muon asymmetry can be partially converted to a desired baryon asymmetry.

Mixed action lattice QCD with Borici-Creutz valence quarks on a staggered sea is investigated. The counterterms in Borici-Creutz action are fixed nonperturbatively to restore the broken parity and time symmetries. When symmetries are restored, the usual signatures of partial quenching are recovered. We find the scalar correlators to be negative for lower valence quark masses, but the error bars are rather large when their mean values are negative at earlier time slices. The size of unitarity violation due to different discretization of valence and sea quarks is determined by measuring ${\mathrm{\Delta }}_{\mathrm{mix}}$ and is found to be comparable with other mixed action studies.

Perturbative QCD in the small Bjorken-$x$ limit can be formulated as an effective theory known as the color glass condensate (CGC) formalism. The CGC formalism takes into account the dynamics of large gluon densities at small $x$ and has been successfully applied to deep inelastic scattering (DIS) and particle production in high-energy hadronic and nuclear collisions in the small-$x$ kinematic region. The effective degrees of freedom in CGC are Wilson lines which enter in the effective quark (and gluon) propagators and resum multiple soft scatterings from the small-$x$ gluon field of the target. It is however known that the CGC effective theory breaks down when one probes the moderately large-$x$ (high-$p_t$) kinematics where collinear factorization and DGLAP evolution of parton distribution functions should be the right framework. Here we propose a general framework which may allow one to eventually unify the two approaches and to calculate perturbative QCD cross sections in both small and large Bjorken-$x$ regions. We take the first step towards this goal by deriving an expression for the quark propagator in a background field which includes scatterings from both small- and large-$x$ modes of the gluon field of the target. We describe how this quark propagator can be used to calculate QCD structure functions $F_2$ and $F_L$ at all $x$ and thus generalize the dipole model of DIS. We outline that this approach can also be used to extend the so-called hybrid approach to particle production in the forward rapidity region of high-energy hadronic and nuclear collisions to all $x$ and $p_t$ regions and speculate on how one may apply the same techniques to extend the McLerran-Venugopalan effective action used in high-energy heavy-ion collisions to include high-$p_t$ physics.

We investigate the chiral symmetry and its spontaneous breaking at finite temperature and in an external magnetic field with four-fermion interactions of different channels. Quantum and thermal fluctuations are included within the functional renormalization group approach, and properties of the set of flow equations for different couplings, such as its fixed points, are discussed. It is found that external parameters, e.g., the temperature and the external magnetic field and so on, do not change the structure of the renormalization group flows for the couplings. The flow strength is found to be significantly dependent on the route and direction in the plane of couplings of different channels. Therefore, the critical temperature for the chiral phase transition shows a pronounced dependence on the direction as well. Given fixed initial ultraviolet couplings, the critical temperature increases with the increasing magnetic field, viz., the magnetic catalysis is observed with initial couplings fixed.

We consider forward inclusive production of two quarks in the high energy p-A collisions in the color-glass-condensate formalism. We demonstrate that the production cross section is determined by the convolution of the proton generalized double transverse momentum-dependent distribution functions with two independent eikonal scattering amplitudes: the product of two dipoles and a quadrupole. We explicitly demonstrate that the quadrupole amplitude term accounts for all the (initial and final state) effects of quantum statistics for identical fermions, and the correlations due to these effects. We also demonstrate that the effects due to quantum statistics (entirely encoded in the quadrupole) are parametrically leading contributions to the correlated particle production at large $N_c$. For nonidentical quarks the quadrupole term also leads to correlated production which (barring accidental cancellations) has characteristics similar to the Hanbury Brown-Twiss effect.

A framework to include triple collinear splitting functions into parton showers is presented, and the implementation of flavor-changing next-to-leading-order (NLO) splitting kernels is discussed as a first application. The correspondence between the Monte Carlo integration and the analytic computation of NLO DGLAP evolution kernels is made explicit for both timelike and spacelike parton evolution. Numerical simulation results are obtained with two independent implementations of the new algorithm, using the two independent event generation frameworks PYTHIA and SHERPA.

We study the production of a Higgs boson in association to a top-antitop pair at the Large Hadron Collider (LHC). We show how precise predictions for the differential distributions with respect to the transverse momentum of the Higgs boson, to the invariant mass of the top-antitop-Higgs system and to the invariant mass of the top-antitop pair can provide useful information on the possible presence of a pseudoscalar component in the coupling of the top quark with the Higgs boson. We evaluate the production of a top-antitop pair and a Higgs boson to next-to-leading order in fixed order perturbation theory and we carry out the resummation of soft emission corrections to next-to-leading-logarithmic accuracy for the LHC operating at a center of mass energy of 13 TeV. We discuss how the shape of these distributions can be employed experimentally, making a physics case for the kinematic reconstruction of dilepton channels.

The semiexclusive channel ${\nu }_{\mu }+\mathrm{CH}\to {\mu }^{-}{\pi }^0+\text{nucleon}(\mathrm{s})$ is analyzed using MINERvA exposed to the low-energy NuMI ${\nu }_{\mu }$ beam with spectral peak at $E_{\nu }\simeq 3\mathrm{GeV}$. Differential cross sections for muon momentum and production angle, ${\pi }^0$ kinetic energy and production angle, and for squared four-momentum transfer are reported, and the cross section $\sigma (E_{\nu })$ is obtained over the range $1.5\mathrm{GeV}\le E_{\nu }<20\mathrm{GeV}$. Results are compared to GENIE and NuWro predictions and to published MINERvA cross sections for charged-current ${\pi }^{+}({\pi }^0)$ production by ${\nu }_{\mu }({\overline{\nu }}_{\mu })$ neutrinos. Disagreements between data and simulation are observed at very low and relatively high values for muon angle and for $Q^2$ that may reflect shortfalls in modeling of interactions on carbon. For ${\pi }^0$ kinematic distributions, however, the data are consistent with the simulation and provide support for generator treatments of pion intranuclear scattering. Using signal-event subsamples that have reconstructed protons as well as ${\pi }^0$ mesons, the $p{\pi }^0$ invariant mass distribution is obtained, and the decay polar and azimuthal angle distributions in the rest frame of the $p{\pi }^0$ system are measured in the region of $\mathrm{\Delta }(1232{)}^{+}$ production, $W<1.4\mathrm{GeV}$.

We study the time development of strongly coupled $\mathcal{N}=4$ supersymmetric Yang Mills (SYM) theory on cosmological Friedmann-Robertson-Walker (FRW) backgrounds via the AdS/CFT correspondence. We implement the cosmological background as a boundary metric fulfilling the Friedmann equation with a four-dimensional cosmological constant and a dark radiation term. We analyze the dual bulk solution of the type IIB supergravity and find that the time dependence of the FRW background strongly influences the dynamical properties of the SYM theory. We in particular find a phase transition between a confined and a deconfined phase. We also argue that some cosmological solutions could be related to the inflationary scenario.

The sigma model of closed strings spinning in the $\eta$ deformation of ${\mathrm{AdS}}_5\times S^5$ leads to an integrable deformation of the one-dimensional Neumann-Rosochatius mechanical system. In this article we construct general solutions to this system that can be written in terms of elliptic functions. The solutions correspond to closed strings with nonconstant radii rotating with two different angular momenta in an $\eta$-deformed three-sphere. We analyze the reduction of the elliptic solutions for some limiting values of the deformation parameter. For the case of solutions with constant radii we find the dependence of the classical energy of the string on the angular momenta as an expansion in the ’t Hooft coupling.

We examine the four-dimensional path integral for Euclidean quantum gravity in the context of the EPRL-FK spin foam model. The state sum is restricted to certain symmetric configurations which resemble the geometry of a flat homogeneous and isotropic universe. The vertex structure is specially chosen so that a basic concept of expansion and contraction of the lattice universe is allowed. We compute the asymptotic form of the spin foam state sum in the symmetry restricted setting and recover a Regge-type action, as well as an explicit form of the Hessian matrix, which captures quantum corrections. We investigate the action in the three cases of vacuum, a cosmological constant, and coupled to dust, and find that in all cases, the corresponding FLRW dynamics is recovered in the limit of large lattices. While this work demonstrates a large intersection with computations done in the context of cosmological modeling with Regge calculus, it is ultimately a setup for treating curved geometries in the renormalization of the EPRL-FK spin foam model.

We investigate the holographic Smarr relation beyond the large $N$ limit. By making use of the holographic dictionary, we find that the bulk correlates of subleading $1/N$ corrections to this relation are related to the couplings in Lovelock gravity theories. We likewise obtain a holographic equation of state and check its validity for a variety of interesting and nontrivial black holes, including rotating planar black holes in Gauss-Bonnet-Born-Infeld gravity, and nonextremal rotating black holes in minimal five-dimensional gauged supergravity. We provide an explanation of the $N$-dependence of the holographic Smarr relation in terms of contributions due to planar and nonplanar diagrams in the dual theory.

We reexamine canonical quantization of the gauged Rarita-Schwinger theory using the extended theory, incorporating a dimension $\frac{1}{2}$ auxiliary spin-$\frac{1}{2}$ field $\mathrm{\Lambda }$, in which there is an exact off-shell gauge invariance. In $\mathrm{\Lambda }=0$ gauge, which reduces to the original unextended theory, our results agree with those found by Johnson and Sudarshan, and later verified by Velo and Zwanziger, which give a canonical Rarita-Schwinger field Dirac bracket that is singular for small gauge fields. In gauge covariant radiation gauge, the Dirac bracket of the Rarita-Schwinger fields is nonsingular, but does not correspond to a positive semidefinite anticommutator, and the Dirac bracket of the auxiliary fields has a singularity of the same form as found in the unextended theory. These results indicate that gauged Rarita-Schwinger theory is somewhat pathological, and cannot be canonically quantized within a conventional positive semidefinite metric Hilbert space. We leave open the questions of whether consistent quantizations can be achieved by using an indefinite metric Hilbert space, by path integral methods, or by appropriate couplings to conventional dimension $\frac{3}{2}$ spin-$\frac{1}{2}$ fields.

Consider a dynamic general relativistic spacetime in which the proper infinitesimal interval along one spatial coordinate direction decreases monotonically with time, while the corresponding intervals increase along other spatial directions. In a system undergoing such complete anisotropic collapse/expansion, we look for the formation of a cosmic double-jet configuration: free test particles in the ambient medium, relative to the collapsing system, gain energy from the gravitational field and asymptotically line up parallel and antiparallel to the direction of collapse such that their Lorentz factors approach infinity. A strong burst of electromagnetic radiation is expected to accompany this event if some of the free test particles carry electric charge. Previous work in this direction involved mainly Ricci-flat spacetimes; hence, we concentrate here on inhomogeneous perfect fluid spacetimes. We briefly explore the possible connection between these theoretical cosmic jets and astrophysical jets. We also discuss other general relativistic scenarios for the formation of cosmic jets.