We compute $2\to 2$ scattering in massive ${\varphi }^4$ theory on ${\mathbb{R}}^{1,m}\times T^n$ to NLO. We perform the calculations using “denominator regularization” instead of the usual dimensional regularization, which allows for asymmetric configurations of the $T^n$. We give a transparent derivation of and equation for the analytic continuation of the generalized Epstein zeta function. We show that the optical theorem is satisfied and generalize a conjecture by Hardy on square counting functions. We comment on the implications.

Noncentral heavy ion collisions lead to the production of a quark gluon plasma with angular momentum. We investigate, using holographic AdS (anti–de Sitter)/QCD models, how does rotation of the medium affects the confinement/deconfinement transition temperature $T_c$. In holographic models, this transition is represented by a Hawking-Page process involving two asymptotically AdS spaces. The plasma is represented here by extending the holographic approach to anti–de Sitter spaces with cylindrical symmetry. Then the rotation of the medium is introduced through a Lorentz boost. We consider hard and soft wall AdS/QCD models. In both cases we find it out that, as the rotational velocity $v$ increases, $T_c$ decreases, following the expression $T_c(v)=T_c(0)/\gamma (v)$, where $\gamma (v)$ is the Lorentz factor.

In this paper we revisit the model of $\kappa$-deformed complex scalar field introduced in our previous paper [M. Arzano et al., Phys. Rev. D 103, 106015 (2021)]. We find that the model possesses ten conserved Noether charges that form, under commutators, a representation of (undeformed) Poincaré algebra, proving that it is relativistic and does not break Lorentz invariance. It turns out, however that the spacetime representation of boosts is not standard and contains a nonlocal translation, different for positive and negative energy modes. It then follows that although the masses of particles and antiparticles are equal, the model violates $CPT$ symmetry in a subtle way. We explain why the Jost-Wightman-Greenberg theorem of equivalence of the Poincaré symmetry and $CPT$ fails in our case. Finally, we discuss the phenomenological consequences of the theory and its possible observational signatures.

Static, spherically symmetric solutions representing stars made of barotropic perfect fluid are studied in the context of two theories of type-II minimally modified gravity, VCDM and VCCDM. Both of these theories share the property that no additional degree of freedom is introduced in the gravity sector, and propagate only two gravitational waves besides matter fields, as in General Relativity (GR). We find that, on imposing physical boundary conditions on the Misner-Sharp mass of the system, the solutions in V(C)CDM exactly coincide with the ones in GR; namely, they also satisfy the Tolman-Oppenheimer-Volkoff equation.

The spherically symmetric steady accretion of polytropic perfect fluids onto a black hole is the simplest flow model that can demonstrate effects of backreaction (self-gravity). It was discovered 16 years ago that backreaction does not influence some (“intensive”) characteristics of sonic points, under suitable conditions. Herein we consider a wider class of polytropic conditions, with polytropic indices in the range (1, 2], and establish detailed boundary conditions that allow one to prove this fact. We find also numerical examples showing limits of our analytic criteria—if suitable analytic conditions are not satisfied, then self-gravity influences all characteristics of sonic points. That fact constrains the applicability of the recent proposal of Baumgarte and Shapiro to estimate the lifetime of black holes within compact stellar objects.

This paper describes the first all-sky search for long-duration, quasimonochromatic gravitational-wave signals emitted by ultralight scalar boson clouds around spinning black holes using data from the third observing run of Advanced LIGO. We analyze the frequency range from 20 to 610 Hz, over a small frequency derivative range around zero, and use multiple frequency resolutions to be robust towards possible signal frequency wanderings. Outliers from this search are followed up using two different methods, one more suitable for nearly monochromatic signals, and the other more robust towards frequency fluctuations. We do not find any evidence for such signals and set upper limits on the signal strain amplitude, the most stringent being $\approx {10}^{-25}$ at around 130 Hz. We interpret these upper limits as both an “exclusion region” in the boson mass/black hole mass plane and the maximum detectable distance for a given boson mass, based on an assumption of the age of the black hole/boson cloud system.

The impact of mesonic fluctuations on the restoration of the $U_A(1)$ anomaly is investigated nonperturbatively for three flavors at finite temperature in an effective model setting. Using the functional renormalization group, the dressed, fully field-dependent Kobayashi-Maskawa-’t Hooft (KMT) anomaly coupling is computed. It is found that mesonic fluctuations strengthen this signature of the $U_A(1)$ breaking as the temperature increases. On the other hand, when instanton effects are included by parametrizing the explicit temperature dependence of the bare anomaly parameter in consistency with the semiclassical result for the tunneling amplitude, a natural tendency appears, diminishing the anomaly at high temperatures. As a result of the two competing effects, the dressed KMT coupling shows a well-defined intermediate strengthening behavior around the chiral (pseudo)transition temperature before the axial anomaly gets fully suppressed at high temperature. As a consequence, we conclude that below $T\sim 200\mathrm{MeV}$ the $U_A(1)$ anomaly is unlikely to be effectively restored. Robustness of the conclusions against different assumptions for the temperature dependence of the bare anomaly coefficient is investigated in detail.

In this erratum, we correct a subset of our numerical results for $s\ne 1$, where $s$ is the sound speed squared, presented in “Relativistic hybrid stars in the light of NICER PSR $\mathrm{J}0740+6620$ radius measurement” [Phys. Rev. D 104, L121302 (2021)]. The results for hybrid stars with $s=1$ remain unchanged.

We show that the integrability of the $SO(N)/SO(N-1)$ principal chiral model (PCM) originates from the Pohlmeyer reduction of the $O(N)$ nonlinear sigma model (NLSM). In particular, we show that the Lax pair of the PCM is related upon redefinitions and identification of parameters to the zero curvature condition, which is a consequence of the flatness of the enhanced space used in the Pohlmeyer reduction. This identification provides the solution of the auxiliary system that corresponds to an arbitrary NLSM/PCM solution.

We study $N=4$ gauged supergravity with an $SO(4)\times SO(4)$ gauge group in the presence of symplectic deformations and find new classes of Janus solutions preserving $N=1$ and $N=2$ supersymmetries. The $N=2$ solutions preserve $SO(2)\times SO(2)\times SO(2)\times SO(2)$ symmetry and interpolate between $N=4$ supersymmetric ${\mathrm{AdS}}_4$ vacua with $SO(4)\times SO(4)$ symmetry. These correspond holographically to $N=(2,0)$ two-dimensional conformal defects within the dual $N=4$ Chern-Simons-Matter (CSM) theories with $SO(4)\times SO(4)$ symmetry. The $N=1$ solutions contain two families of Janus configurations, one interpolating between $N=4$ ${\mathrm{AdS}}_4$ vacua with $SO(4)\times SO(4)$ symmetry and the other interpolating between $N=4$ ${\mathrm{AdS}}_4$ vacua with $SO(3)\times SO(3)\times SO(3)$ symmetry. These describe, respectively, $N=(1,0)$ conformal defects in $N=4$ CSM theories with $SO(4)\times SO(4)$ and $SO(3)\times SO(3)\times SO(3)$ symmetries. The latter give the first example of Janus solutions involving nontrivial ${\mathrm{AdS}}_4$ vacua in addition to the trivial $SO(4)\times SO(4)$ critical point at the origin of the scalar manifold within the framework of $N=4$ gauged supergravity.

We investigate the free energy and entropy of the Gaussian massive scalar field theory in the static de Sitter space-time for arbitrary temperature. For the inverse temperatures of the form $\beta =2\pi 2^k$, $k\in \mathbf{Z}$, in curvature units, we find the explicit form of the free energy and its derivatives with respect to the temperature. There are two types of contributions to the free energy: one is of the “area type” and can be attributed to the horizon, while the other is of the “volume type” and is associated with the interior of the space-time. The latter contribution in the odd-dimensional case in the limit of the week field (large mass or small Hubble constant) significantly depends on the temperature. Namely, for $\beta <2\pi$, the free energy behaves as $F_{\beta }^{\text{bulk}}\sim e^{-\beta m}$, while for $\beta >2\pi$ it behaves as $F_{\beta }^{\text{bulk}}\sim e^{-2\pi m}$. We also show that even the leading UV contributions to the free energy significantly depend on the state of the theory, which is very unusual. We explain the origin and physical meaning of these observations. As the model example we consider the situation in the Rindler wedge of the flat space-time.

Bootstrapped Newtonian gravity is a nonlinear version of Newton’s law, which can be lifted to a fully geometric theory of gravity starting from a modified potential. Here, we study geodesics in the bootstrapped Newtonian effective metric in vacuum and obtain bounds on a free parameter from Solar System data and $S$-star orbits near our Galaxy center. These bounds make vacuum bootstrapped Newtonian gravity experimentally indistinguishable from General Relativity.

We discuss particle production in spacetimes endowed with a universal horizon in Einstein-aether and Hořava gravity. We argue that continuity and differentiability of the lapse function require the orientation of the foliation in the interior of the horizon to be reversed with respect to the exterior one. Unless this is allowed, interaction of gravitating scalar fields with the universal horizon leads to unitarity violations in the quantum theory. This property is responsible for particle production by the universal horizon, as we show by computing explicitly its Hawking temperature for all stationary and spherically symmetric spacetimes. We particularize our result to known analytic solutions, including those compatible with observational constraints.

Perturbation theory (PT) has been used to interpret the observed nonlinear large-scale structure statistics in the quasilinear regime. To facilitate the PT-based analysis, we have presented the GridSPT algorithm, a grid-based method to compute the nonlinear density and velocity fields in standard perturbation theory (SPT) from a given linear power spectrum. Here, we expand on this approach by taking the redshift-space distortions into account. With the new implementation, we generate for the first time the redshift-space density field to the fifth order and computed the next-to-next-to-leading-order (two-loop) power spectrum and the next-to-leading-order (one-loop) bispectrum of matter clustering in redshift space. By comparing the result with the corresponding analytical SPT calculation and $N$-body simulations, we find that the SPT calculation (A) suffers much more from UV sensitivity due to the higher-derivative operators, and (B) deviates from the $N$-body results above the Fourier wave number smaller than real space $k_{\max }$. Finally, we show that while the Padé approximation removes spurious features in the morphology, it does not improve the modeling of the power spectrum and bispectrum.

Self-gravitating quantum matter may exist in a wide range of cosmological and astrophysical settings from the very early universe through to present-day boson stars. Such quantum matter arises in a number of different theories, including the Peccei-Quinn axion and ultralight (ULDM) or fuzzy dark matter scenarios. We consider the dynamical evolution of perturbations to the spherically symmetric soliton, the ground state solution to the Schrödinger-Poisson system common to all these scenarios. We construct the eigenstates of the Schrödinger equation, holding the gravitational potential fixed to its ground state value. We see that the eigenstates qualitatively capture the properties seen in full ULDM simulations, including the soliton “breathing” mode, the random walk of the soliton center, and quadrupolar distortions of the soliton. We then show that the time evolution of the gravitational potential and its impact on the perturbations can be well described within the framework of time-dependent perturbation theory. As an illustrative example, we apply our formalism to a synthetic ULDM halo. We find the soliton core accounts for approximately 30% of the halo’s wave function throughout its evolution, with higher modes accounting for the halo’s Navarro-Frenk-White skirt, and relatively little mixing between different $\ell$ modes. Our results provide a new analytic approach to understanding the evolution of these systems as well as possibilities for faster approximate simulations.

We analyze the effects of chiral symmetry restoration in hadronic matter, including the lowest-lying baryonic resonance $\mathrm{\Delta }$ based on the parity doublet model. We study the role of $\mathrm{\Delta }$ and its chiral partner on the equation of state of dense matter under neutron star conditions of $\beta$ equilibrium and charge neutrality. We find that the softening of the equation of state driven by the early onset of $\mathrm{\Delta }$ matter due to partial restoration of chiral symmetry allows accommodating the modern multimessenger astrophysical constraints on the mass, radius, and tidal deformability. The softening above the saturation density is accompanied by subsequent stiffening at high densities. We also find that the matter composition in the neutron star cores may be different upon variations of the repulsive interactions of $\mathrm{\Delta }$ baryons in hadronic matter.

The gamma-ray halo around Geminga is formed owing to the slow diffusion of the electrons released by the Geminga pulsar wind nebula (PWN). The latest observations from the HAWC and H.E.S.S. Collaborations exhibit complex features in the TeV gamma-ray spectrum of the Geminga halo. We first show that the new results cannot be interpreted by the commonly used simple model, where a single power-law injection spectrum and an energy index of $\delta =1/3$ for the diffusion coefficient are assumed. We then propose a two-population electron injection model based on the x-ray observations of the Geminga PWN, which consists of a population of freshly accelerated electrons escaping from the PWN through rapid outflows and a population trapped longer inside the PWN before escaping. The two-population model interprets the HAWC and H.E.S.S. data well, and the goodness of fit improves significantly compared with the single power-law injection model. It also predicts a different energy dependency of the gamma-ray profile from the single power-law injection model, which could be tested by the Large High Altitude Air Shower Observatory in the coming future. We note that a $\delta$ slightly larger than 1 is needed to fit the HAWC and H.E.S.S. data consistently. We also discuss the possible improvements by adopting the two-zone diffusion model.

The lack of evidence for new interactions and particles at the Large Hadron Collider (LHC) has motivated the high-energy physics community to explore model-agnostic data-analysis approaches to search for new physics. Autoencoders are unsupervised machine learning models based on artificial neural networks, capable of learning background distributions. We study quantum autoencoders based on variational quantum circuits for the problem of anomaly detection at the LHC. For a QCD $t\overline{t}$ background and resonant heavy-Higgs signals, we find that a simple quantum autoencoder outperforms classical autoencoders for the same inputs and trains very efficiently. Moreover, this performance is reproducible on present quantum devices. This shows that quantum autoencoders are good candidates for analysing high-energy physics data in future LHC runs.

The nuclear medium effects in the nuclear structure functions and differential cross sections in the deep inelastic scattering (DIS) of charged lepton and neutrino from nuclear targets are studied in the region of large $x$ including $x\ge 1$. The nuclear medium effects due to the Fermi motion and the binding energy of nucleons and the nucleon correlations are included using nucleon spectral function calculated in a microscopic field theoretical model. The numerical results for the nuclear structure functions and the cross sections are obtained using the nucleon structure function evaluated at the next-to-next-to-leading order (NNLO) with the Martin-Motylinski-Harland Lang-Thorne (MMHT) parametrization of the nucleonic parton distribution functions (PDFs) and are compared with the available experimental data on electron scattering from the Jefferson Lab (JLab) and SLAC Nuclear Physics Facility (NPAS). In the case of neutrino scattering the results are relevant for understanding the DIS contributions to the recent inclusive cross sections measured by the Main Injector Neutrino Experiment to study v-A interactions (MINERvA) as well as theoretical predictions are made for Deep Underground Neutrino Experiment (DUNE). The importance of isoscalarity corrections in heavier nuclear targets as well as the effect of the kinematic cut on the CM energy $W$ in defining the DIS region have also been discussed.