We calculate the three- and four-loop corrections to the massless fermion propagator in three-dimensional quenched quantum electrodynamics with four-component fermions. The three-loop correction is finite and gauge invariant but the four-loop one has singularities except in the Feynman gauge where it is also finite. Our results explicitly show that, up to four loops, gauge-dependent terms are completely determined by lower order ones in agreement with the Landau-Khalatnikov-Fradkin transformation.

A solution to the black hole information problem requires propagation of information from the interior of the black hole to the exterior. Such propagation violates general relativity and could conceivably be accomplished through “firewall” models. Based on the existence of similar firewalls at the inner horizons of charged and rotating black holes, a model of a firewall was recently constructed where the exterior spacetime reduces to that of the Schwarzschild metric but with a dramatically different interior. We investigate the radial and nonradial polar stability of these objects. We first study the dynamics of the shell under spherically symmetric perturbations, and impose constraints on the firewall model parameters by requiring a subluminal speed of sound on the firewall. We show that the demands of stability and subluminality impose significant constraints on the internal parameters of the firewall, narrowing down the range of objects that could be used to create such a structure.

We present a new convenient framework for modeling Reissner-Nordström black hole perturbations from charged distributions of matter. Using this framework, we quantify how gravitational wave observations of compact binary systems would be affected if one or both components were charged. Our approach streamlines the (linearized) Einstein-Maxwell equations through convenient master functions that we designed to ameliorate certain disadvantages of prior strategies. By solving our improved master equations with a point source, we are able to quantify the rate of orbital energy dissipation via electromagnetic and gravitational radiation. Through adiabatic and quasicircular approximations, we apply our dissipative calculations to determine trajectories for intermediate and extreme mass-ratio inspirals. By comparing trajectories and waveforms with varied charges to those with neutral components, we explore the potential effect of electric charge on gravitational wave signals. We observe that the case of opposite charge-to-mass-ratios has the most dramatic impact. Our findings are largely interpreted through the lens of the upcoming laser interferometer space antenna mission.

We investigate the deflection angle in a strong deflection limit for a marginally unstable photon sphere in a general asymptotically flat, static and spherically symmetric spacetime under some assumptions to calculate observables. The deflection angle of a light ray reflected by the marginally unstable photon sphere diverges nonlogarithmically while the one for a photon sphere diverges logarithmically. We apply our formula to a Reissner-Nordström spacetime and Hayward spacetime.

We show that initial conditions for small-field inflation can be determined quantum mechanically by introducing a suitable flattened region in the scalar potential. The inflaton is then driven toward the slow-roll attractor solution exponentially fast, desensitizing inflation from the initial velocity and partially evading the so-called overshoot problem. We give an explicit example in the context of hilltop inflation by introducing an ultra-slow-roll plateau around the maximum of the potential and analyze its effect on the phase-space trajectories.

The uncertainty principle, first introduced by Heisenberg in inertial frames, clearly distinguishes quantum theories from classical mechanics. In noninertial frames, its information-theoretic expressions, namely, entropic uncertainty relations, have been extensively studied through delocalized quantum fields, and localization of the quantum fields were discussed as well. However, infeasibility of measurements applied on a delocalized quantum field due to the finite size of measurement apparatuses is left unexplained. Therefore, physical clarification of a quantum protocol revealing entropic uncertainty relations still needs investigation. Building on advances in quantum field theories and theoretical developments in entropic uncertainty relations, we demonstrate a relativistic protocol of an uncertainty game in the presence of localized fermionic quantum fields inside cavities. Moreover, a novel lower bound for entropic uncertainty relations with multiple quantum memories is given in terms of the Holevo quantity, which implies how acceleration affects uncertainty relations.

We demonstrate that spontaneous transverse polarization of lambda baryon ($\mathrm{\Lambda }$) production in $e^{+}{e}^{-}$ annihilation can be described using the transverse momentum dependent polarizing fragmentation functions (TMD PFFs). Using a simple Gaussian model, we perform an extraction of the TMD PFFs by fitting the BELLE Collaboration’s recent measurement of the $\mathrm{\Lambda }$ transverse polarization in back-to-back $\mathrm{\Lambda }+h$ production in $e^{+}{e}^{-}$ collisions, $e^{-}+e^{+}\to {\mathrm{\Lambda }}^{\uparrow }+h+X$. We find that this simple model accurately describes the experimental data for $\mathrm{\Lambda }$ production associated with pions and kaons, and we are able to determine TMD PFFs for different quark flavors. We use these newly extracted TMD PFFs to make predictions for the transverse polarization of $\mathrm{\Lambda }$ produced in semi-inclusive deep inelastic scattering at a future electron-ion collider and find that such a polarization is around 10% and should be measurable. Furthermore, the extracted TMD PFFs have been made available open source.

In this work, we investigate the interactions between the charmed-strange meson ($D_s,D_s^{*}$) in $H$-doublet and the (anti-)charmed-strange meson ($D_{s1},D_{s2}^{*}$) in $T$-doublet, where the one boson exchange model is adopted by considering the $S\text{−}D$ wave mixing and the coupled-channel effects. By extracting the effective potentials for the discussed $H_s{\overline{T}}_s$ and $H_s{T}_s$ systems, we try to find the bound state solutions for the corresponding systems. We predict the possible hidden-charm hadronic molecular states with hidden strangeness, i.e., the $D_s^{*}{\overline{D}}_{s1}+c.c.$ states with $J^{PC}=0^{--},0^{-+}$ and the $D_s^{*}{\overline{D}}_{s2}^{*}+c.c.$ states with $J^{PC}=1^{--},1^{-+}$. Applying the same theoretical framework, we also discuss the $H_s{T}_s$ systems. Unfortunately, the existence of the open-charm and open-strange molecular states corresponding to the $H_s{T}_s$ systems can be excluded.

We calculate the dressed gluon and ghost propagators of Landau gauge Yang-Mills theory in the complex momentum plane from their Dyson-Schwinger equations. To this end, we develop techniques for a direct calculation such that no mathematically ill-posed inverse problem needs to be solved. We provide a detailed account of the employed ray technique and discuss a range of tools to monitor the stability of the numerical calculation. Within a truncation employing model Ansätze for the three-point vertices and neglecting effects due to four-point functions, we find a singularity in the gluon propagator in the second quadrant of the complex $p^2$ plane. Although the location of this singularity turns out to be strongly dependent on the model for the three-gluon vertex, it always occurs at complex momenta for the range of models considered.

Dual-phase xenon detectors, as currently used in direct detection dark matter experiments, have observed elevated rates of background electron events in the low energy region. While this background negatively impacts detector performance in various ways, its origins have only been partially studied. In this paper we report a systematic investigation of the electron pathologies observed in the LUX dark matter experiment. We characterize different electron populations based on their emission intensities and their correlations with preceding energy depositions in the detector. By studying the background under different experimental conditions, we identified the leading emission mechanisms, including photoionization and the photoelectric effect induced by the xenon luminescence, delayed emission of electrons trapped under the liquid surface, capture and release of drifting electrons by impurities, and grid electron emission. We discuss how these backgrounds can be mitigated in LUX and future xenon-based dark matter experiments.

The cross section of bottom quark-antiquark ($b\overline{b}$) production in $p+p$ collisions at $\sqrt{s}=510\mathrm{GeV}$ is measured with the PHENIX detector at the Relativistic Heavy Ion Collider. The results are based on the yield of high mass, like-sign muon pairs measured within the PHENIX muon arm acceptance ($1.2<|y|<2.2$). The $b\overline{b}$ signal is extracted from like-sign dimuons by utilizing the unique properties of neutral $B$ meson oscillation. We report a differential cross section of $d{\sigma }_{b\overline{b}\to {\mu }^{\pm }{\mu }^{\pm }}/dy=0.16\pm 0.01(\mathrm{stat})\pm 0.02(\mathrm{syst})\pm 0.02(\text{global})\mathrm{nb}$ for like-sign muons in the rapidity and $p_T$ ranges $1.2<|y|<2.2$ and $p_T>1\mathrm{GeV}/c$, and dimuon mass of $5–10\mathrm{GeV}/c^2$. The extrapolated total cross section at this energy for $b\overline{b}$ production is $13.1\pm 0.6(\mathrm{stat})\pm 1.5(\mathrm{syst})\pm 2.7(\text{global})\mu \mathrm{b}$. The total cross section is compared to a perturbative quantum chromodynamics calculation and is consistent within uncertainties. The azimuthal opening angle between muon pairs from $b\overline{b}$ decays and their $p_T$ distributions are compared to distributions generated using ps pythia6, which includes next-to-leading order processes. The azimuthal correlations and pair $p_T$ distribution are not very well described by pythia calculations, but are still consistent within uncertainties. Flavor creation and flavor excitation subprocesses are favored over gluon splitting.

The off-shell massless six-point double box and hexagon conformal Feynman integrals with generic propagator powers are expressed in terms of linear combinations of multiple hypergeometric series of the generalized Horn type. These results are derived from 9-fold Mellin-Barnes representations obtained from their dual conformal Feynman parameter representations. The individual terms in the presented expressions satisfy the differential equation that relates the double box in $D$ dimensions to the hexagon in $D+2$ dimensions.

In the large-$N$ and strong-coupling limit, maximally supersymmetric $\mathrm{SU}(N)$ Yang-Mills theory in ($2+1$) dimensions is conjectured to be dual to the decoupling limit of a stack of $N$ D2-branes, which may be described by IIA supergravity. We study this conjecture in the Euclidean setting using nonperturbative lattice gauge theory calculations. Our supersymmetric lattice construction naturally puts the theory on a skewed Euclidean 3-torus. Taking one cycle to have antiperiodic fermion boundary conditions, the large-torus limit is described by certain Euclidean black holes. We compute the bosonic action—the variation of the partition function—and compare our numerical results to the supergravity prediction as the size of the torus is changed, keeping its shape fixed. Our lattice calculations primarily utilize $N=8$ with extrapolations to the continuum limit, and our results are consistent with the expected gravity behavior in the appropriate large-torus limit.

In this paper, we examine the proposed first law of holographic complexity through studying different perturbations around various spacetime backgrounds. We present a general expression for the variation of the holographic complexity on arbitrary backgrounds by an explicit covariant computation. Interestingly, the general expression can be written as a function of gravitational conserved charges reminiscent of the first law of thermodynamics.

In this paper, we compute the higher derivative amplitudes arising from shift symmetric-invariant actions for both the nonlinear sigma model and the special Galileon symmetries, and provide explicit expressions for their Lagrangians. We find that, beyond leading order, the equivalence between shift symmetries, enhanced single soft limits, and compatibility with the double copy procedure breaks down. In particular, we have shown that the most general even-point amplitudes of a colored scalar satisfying the Kleiss-Kuijf and Bern-Carrasco-Johansson relations are compatible with the nonlinear sigma model symmetries. Similarly, their double copy is compatible with the special Galileon symmetries. We showed this by fixing the dimensionless coefficients of these effective field theories in such a way that the arising amplitudes are compatible with the double copy procedure. We find that this can be achieved for the even-point amplitudes but not for the odd ones. These results imply that not all operators invariant under the shift symmetries under consideration are compatible with the double copy.

We study the modular symmetry in $T^2$ and orbifold comfactifications with magnetic fluxes. There are $|M|$ zero modes on $T^2$ with the magnetic flux $M$. Their wave functions as well as massive modes behave as modular forms of weight $1/2$ and represent the double covering group of $\mathrm{\Gamma }\equiv SL(2,\mathbb{Z})$, $\tilde{\mathrm{\Gamma }}\equiv \widetilde{SL}(2,\mathbb{Z})$. Each wave function on $T^2$ with the magnetic flux $M$ transforms under $\tilde{\mathrm{\Gamma }}(2|M|)$, which is the normal subgroup of $\widetilde{SL}(2,\mathbb{Z})$. Then, $|M|$ zero modes are representations of the quotient group ${\tilde{\mathrm{\Gamma }}}_{2|M|}^{\prime }\equiv \tilde{\mathrm{\Gamma }}/\tilde{\mathrm{\Gamma }}(2|M|)$. We also study the modular symmetry on twisted and shifted orbifolds $T^2/{\mathbb{Z}}_N$. Wave functions are decomposed into smaller representations by eigenvalues of twist and shift. They provide us with reduction of reducible representations on $T^2$.

We present a relativistic effective field theory for the interaction between acoustic and gapped phonons in the limit of a small gap. We show that, while the former are the Goldstone modes associated with the spontaneous breaking of spacetime symmetries, the latter are pseudo-Goldstones associated with some (small) explicit breaking. We hence dub them “pseudoacoustic” phonons. In this first investigation, we build our effective theory for the cases of one and two spatial dimensions, two atomic species, and assuming large distance isotropy. As an illustrative example, we show how the theory can be applied to compute the total lifetime of both acoustic and pseudoacoustic phonons. This construction can find applications that range from the physics of bilayer graphene to sub-GeV dark matter detectors.

We consider a set of physical degrees of freedom coupled to a finite-dimensional Hilbert space, which may be taken as modeling a fuzzy space or as the lowest Landau level of a Landau-Hall problem. These may be viewed as matter fields on a fuzzy space. Sequentially generalizing to arbitrary backgrounds, we argue that the effective action is given by the Chern-Simons form associated with the Dirac index density (with gauge and gravitational fields), with an Abelian gauge field shifted by the Poincaré-Cartan form for matter dynamics. The result is an action for matter fields where the Lagrangian is integrated with a density which is a specific polynomial in the curvatures.

We discover a new class of topological solitons. These solitons can exist in a space of infinite volume like, e.g., ${\mathbb{R}}^n$, but they cannot be placed in any finite volume because the resulting formal solutions have infinite energy. Therefore, these objects are interpreted as totally incompressible solitons. As a first particular example, we consider ($1+1$)-dimensional kinks in theories with a nonstandard kinetic term or, equivalently, in models with the so-called runaway (or vacuumless) potentials. But incompressible solitons also exist in higher dimensions. As specific examples, in ($3+1$) dimensions we study Skyrmions in the dielectric extensions of both the minimal and BPS Skyrme models. In the latter case, the Skyrmionic matter describes a completely incompressible topological perfect fluid.