The statistics of thermal gas pressure are a new and promising probe of cosmology and astrophysics. The large-scale cross-correlation between galaxies and the thermal Sunyaev-Zeldovich effect gives the bias-weighted mean electron pressure, $⟨b_{\mathrm{h}}{P}_e⟩$. In this paper, we show that $⟨b_{\mathrm{h}}{P}_e⟩$ is sensitive to the amplitude of fluctuations in matter density, for example $⟨b_{\mathrm{h}}{P}_e⟩\propto {({\sigma }_8{\mathrm{\Omega }}_{\mathrm{m}}^{0.81}{h}^{0.67})}^{3.14}$ at redshift $z=0$. We find that at $z<0.5$ the observed $⟨b_{\mathrm{h}}{P}_e⟩$ is smaller than that predicted by the state-of-the-art hydrodynamical simulations of galaxy formation, MillenniumTNG, by a factor of 0.93. This can be explained by a lower value of ${\sigma }_8$ and ${\mathrm{\Omega }}_{\mathrm{m}}$, similar to the so-called “$S_8$ tension” seen in the gravitational lensing effect, although the influence of astrophysics cannot be completely excluded. The difference between Magneticum and MillenniumTNG at $z<2$ is small, indicating that the difference in the galaxy formation models used by these simulations has little impact on $⟨b_{\mathrm{h}}{P}_e⟩$ at this redshift range. At higher $z$, we find that both simulations are in a modest tension with the existing upper bounds on $⟨b_{\mathrm{h}}{P}_e⟩$. We also find a significant difference between these simulations there, which we attribute to a larger sensitivity to the galaxy formation models in the high redshift regime. Therefore, more precise measurements of $⟨b_{\mathrm{h}}{P}_e⟩$ at all redshifts will provide a new test of our understanding of cosmology and galaxy formation.

In recent times the role of space weather on the functioning of the Earth- and space-based technological systems is attracting increasing attention due to the recognition of its potential to adversely impact those systems, especially during the extreme geomagnetic storms. On the other hand, the effects of space weather on the propagation of the galactic cosmic rays (GCRs) can be used to probe the parameters characterizing the space weather. Within the heliosphere, the embedded turbulent magnetic field in the solar wind creates a radial density gradient in an otherwise isotropic distribution of the GCRs. The diffusion-convection framework predicts that the variations in the GCR intensity, and the solar wind velocity should be anticorrelated. In the work presented here, these measurements are extended to the GRAPES-3 data collected over a long interval of 22 years from 2000 to 2021. The “$HK$” parameter is defined as the magnitude of ratio of the rate of change of muon intensity relative to that of the solar wind velocity. Here, the radial diffusion coefficient ${\kappa }_{rr}$, and the parallel mean free path ${\lambda }_{\parallel }$ have been inferred based on several simplifying assumptions, along nine independent directions each of which corresponds to a different median GCR rigidity. Each of these parameters including the $HK$ show a strong correlation with the F10.7 Index, which is an excellent proxy for the 11 year solar activity. This possibly is the first measurement of the parameters that influence the transport of GCRs in the heliosphere, and their dependence on the solar activity at relatively high-median rigidities (64–92 GV) by a ground-based instrument. These measurements should put the link between the space weather, and the high-rigidity GCRs on a much sounder footing, and sheds some light on the complex relationship among the parameters that characterize the space weather.

Sterile neutrinos with masses up to $\mathcal{O}(100)\mathrm{MeV}$ can be copiously produced in a supernova (SN) core through the mixing with active neutrinos. In this regard, the SN 1987A detection of neutrino events has been used to put constraints on active-sterile neutrino mixing, exploiting the well-known SN cooling argument. We refine the calculation of this limit including neutral current interactions with nucleons, which constitute the dominant channel for sterile neutrino production. We also include, for the first time, the charged current interactions between sterile neutrinos and muons, relevant for the production of sterile neutrinos mixed with muon neutrinos in the SN core. Using the recent modified luminosity criterion, we extend the bounds to the case where sterile states are trapped in the stellar core. Additionally, we study the decays of heavy sterile neutrinos, affecting the SN explosion energy and possibly producing a gamma-ray signal. We also illustrate the complementarity of our new bounds with cosmological bounds and laboratory searches.

We have discovered a new phenomenon in high-energy atmospheric physics involving an increased fraction of ground-level positrons during a thunderstorm. This increase is linked to developing a lower positively charged region (LPCR) at the thundercloud bottom. When the electric field strength in the lower atmosphere exceeds a critical value, seed electrons from cosmic rays accelerate and multiply, creating relativistic runaway avalanches of millions of electrons and gamma rays with energies up to 50 MeV. The emerging LPCR changes the polarity of the electric field nearly to the Earth’s surface, causing electrons to decelerate and positrons to accelerate, increasing the flux of 511 keV “annihilation” gamma rays. By measuring these gamma rays, we can reveal the formation of the LPCR and follow the dynamics of the charge structure in the lower part of the thundercloud.

Vacuum birefringence produces a differential phase between orthogonally polarized components of a weak electromagnetic probe in the presence of a strong electromagnetic field. Despite representing a hallmark prediction of quantum electrodynamics, vacuum birefringence remains untested in pure light configurations due to the extremely large electromagnetic fields required for a detectable phase difference. Here, we exploit the programmable focal velocity and extended focal range of a flying focus laser pulse to substantially lower the laser power required for detection of vacuum birefringence. In the proposed scheme, a linearly polarized x-ray probe pulse counterpropagates with respect to a flying focus pulse, whose focus moves at the speed of light in the same direction as the x-ray probe. The peak intensity of the flying focus pulse overlaps the probe over millimeter-scale distances and induces a polarization ellipticity on the order of ${10}^{-10}$, which lies within the detection sensitivity of existing x-ray polarimeters.

We study the higher-order anisotropy coefficients $v_4$ and $v_6$ in the photon and dilepton emission from a hot magnetized quark-gluon plasma. Together with the earlier predictions for $v_2$, these results show a distinctive pattern of the anisotropy coefficients in several kinematic regimes. In the case of photon emission, nonzero coefficients $v_n$ (with even $n$) have opposite signs at small and large values of the transverse momentum (i.e., $k_T\lesssim \sqrt{|eB|}$ and $k_T\gtrsim \sqrt{|eB|}$, respectively). Additionally, the $v_n$ signs alternate with increasing $n$, and their approximate values decrease as $1/n^2$ in magnitude. The anisotropy of dilepton emission is well pronounced only at large transverse momenta and small invariant masses (i.e., when $k_T\gtrsim \sqrt{|eB|}$ and $M\lesssim \sqrt{|eB|}$). The corresponding $v_4$ and $v_6$ coefficients are of the same magnitude and show a similar alternating sign pattern with increasing $n$ as in the photon emission.

We study the magnetized strangelets in the baryon density-dependent quark mass model, including the effects of both confinement and lead-order perturbation interactions. The properties of magnetized strangelets are investigated under the field strength $2\times {10}^{17}\mathrm{G}$, where the anisotropy caused by the strong magnetic field is insignificant and can be treated approximately as an isotropic system. The consideration of anomalous magnetic moments in the energy spectrum naturally solves the difficulty of infrared divergence encountered in integrating the density of states. The Coulomb interaction is accounted for using a self-consistent treatment. The energy per baryon, mechanically stable radius, strangeness, and electric charge of magnetized strangelets are presented, where their dependence on the field strength and parameter of confinement and perturbation are investigated.

Reconstructing the trajectories of charged particles from the collection of hits they leave in the detectors of collider experiments like those at the Large Hadron Collider (LHC) is a challenging combinatorics problem and computationally intensive. The tenfold increase in the delivered luminosity at the upgraded High Luminosity LHC will result in a very densely populated detector environment. The time taken by conventional techniques for reconstructing particle tracks scales worse than quadratically with track density. Accurately and efficiently assigning the collection of hits left in the tracking detector to the correct particle will be a computational bottleneck and has motivated studying possible alternative approaches. This paper presents a quantum-enhanced machine learning algorithm that uses a support vector machine (SVM) with a quantum-estimated kernel to classify a set of three hits (triplets) as either belonging to or not belonging to the same particle track. The performance of the algorithm is then compared to a fully classical SVM. The quantum algorithm shows an improvement in accuracy versus the classical algorithm. Model complexity metrics are used to hint at an explanation for favorable performance of the quantum kernel.

It is well known that the entanglement entropies for spacelike subregions, and the associated modular Hamiltonians play a crucial role in the bulk reconstruction program within anti–de Sitter (AdS) holography. Explicit examples of the Hamilton-Kabat-Lifschytz-Lowe (HKLL) map exist mostly for the cases where the emergent bulk region is the so-called entanglement wedge of the given boundary subregion. However, motivated from the complex pseudoentropy in Euclidean conformal field theories (CFT), one can talk about a “timelike entanglement” in Lorentzian CFTs dual to AdS spacetimes. One can then utilize this boundary timelike entanglement to define a boundary “timelike modular Hamiltonian.” We use constraints involving these Hamiltonians in a manner similar to how it was used for spacelike cases, and write down bulk operators in regions which are not probed by an RT surface corresponding to a single CFT. In the context of two-dimensional CFT, we rederive the HKLL formulas for free bulk scalar fields in three examples: in AdS Poincaré patch, inside and outside of the AdS black hole, and for de Sitter flat slicings. In this method, one no longer requires the knowledge of bulk dynamics for subhorizon holography.

We consider the Witten-Sakai-Sugimoto model in the approximation of smeared instantons at finite density via a homogeneous ansatz, which is known to be discontinuous in order to be able to contain a nonvanishing baryon density. The discontinuity at the infrared tip of the bulk spacetime gives rise to subtleties of discarding boundary terms that are normally discarded in the literature. We propose a reason for discarding this boundary term, by scrutinizing the currents and topological properties of the model. Along the way, we find a very effective and simple condition to compute the point of thermodynamic equilibrium.

From the perspective of effective field theory (EFT), Wilson coefficients of the low energy theory are determined by integrating out modes of the full ultraviolet (UV) theory. The spectrum can be in principle resummed if one has access to all available infrared (IR) coefficients at low energies. In this work we show that there exists a general class of consistent massive resonance double-copy (CMRDC) models where UV massive residues are reconstructed through double-copy consistency conditions between the IR Wilson coefficients of the full EFT expansion. Through a color-dual bootstrap, we find surprisingly that double-copy consistency alone introduces the kinematic factors of CMRDC models that soften high energy behavior by exponentiating color-dual contacts. This bootstrap suggests that our massive resonance paradigm is an inevitable consequence of the duality between color and kinematics, thereby providing a path towards emergent UV structure directly from the IR. We then demonstrate how CMRDC models can capture a spectrum of massive modes compatible with general multiplicity, and use Padé extrapolation to solve the inverse problem of identifying massive UV resonance from a small number of IR Wilson coefficients.

The Bardeen black hole stands as the first model of a regular black hole. Driven by the interpretations of Bardeen spacetime as a quantum-corrected Schwarzschild-like solution, we study quasinormal modes of a massive scalar field within this context. We have found that the damping rate of the massive scalar field decreases as the mass grows, leading to appearance of the arbitrarily long-lived modes. or quasiresonances. The massive term in the Bardeen case is also distinctive in two other respects. First, the overtones deviate from their massless limit at a much smaller rate than the fundamental mode, when the mass is turned on. This behavior overlaps with the so called outburst of overtones, which is deviation of overtones from their Schwarzschild values at an increasingly higher rate than happens for the fundamental mode. This high sensitivity of overtones occurs due to the quantum deformation near the event horizon. Finally, integration in the time domain shows that the oscillatory tails decay as $\sim t^{-(\frac{8}{6}+\ell )}$ at intermediate times and as $\sim t^{-1}$ at asymptotically late times, which is different from the Reissner-Nordström and Schwarzschild limits.

We present a four-dimensional generally covariant gauge theory with local degrees of freedom which leads to the Gauss constraint but lacks both the Hamiltonian and spatial diffeomorphism constraints. The canonical theory therefore resembles Yang-Mills theory without the Hamiltonian. We describe its observables, quantization, and some generalizations.

In the first three observation runs, ground-based gravitational wave (GW) detectors have observed close to $\sim 100$ compact binary coalescence events. The GW detection rates for compact binary coalescences are expected to increase with improvements in the sensitivity of the International Gravitational-Wave Observatory Network. However, with improved sensitivity, non-Gaussian instrumental transients or “glitches” are expected to adversely affect GW searches and characterization algorithms. The most detrimental effect is due to short-duration glitches, which mimic the morphology of short-duration GW transients, in particular intermediate-mass black hole (IMBH) binaries. They can be easily misidentified as astrophysical signals by current searches, and if included in astrophysical analyses, glitches mislabeled as IMBH binaries can affect IMBH population studies. In this work, we introduce a new similarity metric that quantifies the consistency of astrophysical parameters across the detector network and helps to distinguish between IMBH binaries and short-duration, loud glitches which mimic IMBH binaries. We develop this method using a simulated set of IMBH binary signals and a collection of noise transients identified during the third observing run of the Advanced LIGO and Advanced Virgo detectors.

We propose a new method to hunt for dark matter using dark forest/absorption features across the whole electromagnetic spectrum from radio to gamma rays, especially in the bands where there is a desert, i.e., regions where no strong lines from baryons are expected. Such novel signatures can arise for dark matter models with a composite nature and internal electromagnetic transitions. The photons from a background source can interact with the dark matter resulting in an absorption signal in the source spectrum. In case of a compact source, such as a quasar, such interactions in the dark matter halos can produce a series of closely spaced absorption lines, which we call the dark forest. We show that the dark forest feature is a sensitive probe of the dark matter self-interactions and the halo mass function, especially at the low mass end. There is a large volume of parameter space where dark forest is more sensitive compared to the best current and proposed direct detection experiments. Moreover, the absorption of cosmic microwave background (CMB) photons by dark matter gives rise to a global absorption signal in the CMB spectrum. For dark matter transition energies in the range $2.5\times {10}^{-4}-5\times {10}^3\mathrm{eV}$, such absorption features result in spectral distortions of the CMB in the COBE/FIRAS band of 60–600 GHz. If the dark matter transition frequency is in the 100–200 GHz range, we show that the absorption of CMB photons by dark matter can provide an explanation for the anomalous absorption feature detected by the EDGES collaboration in the 50–100 MHz range.

The matter power spectrum $P(k)$ is one of the main quantities connecting observational and theoretical cosmology. Although for a fixed redshift this can be numerically computed very efficiently by Boltzmann solvers, an analytical description is always desirable. However, accurate fitting functions for $P(k)$ are only available for the concordance model. Taking into account that forthcoming surveys will further constrain the parameter space of cosmological models, it is also of interest to have analytical formulations for $P(k)$ when alternative models are considered. Here, we use the genetic algorithms, a machine learning technique, to find a parametric function for $P(k)$ considering several possible effects imprinted by modifications of gravity. Our expression for the $P(k)$ of modified gravity shows a mean accuracy of around 1–2% when compared with numerical data obtained via modified versions of the Boltzmann solver class, and thus it represents a competitive formulation given the target accuracy of forthcoming surveys.

We show how to use the cubic-quintic Gross-Pitaevskii-Poisson equation (cq-GPPE) and the cubic-quintic stochastic Ginzburg-Landau-Poisson equation (cq-SGLPE) to investigate the gravitational collapse of a tenuous axionic gas into a collapsed axionic condensate for both zero and finite temperature $T$. At $T=0$, we use a Gaussian Ansatz for a spherically symmetric density to obtain parameter regimes in which we might expect to find compact axionic condensates. We then go beyond this Ansatz, by using the cq-SGLPE to investigate the dependence of the axionic condensate on the gravitational strength $G$ at $T=0$. We demonstrate that, as $G$ increases, the equilibrium configuration goes from a tenuous axionic gas, to flat sheets or Zeldovich pancakes, cylindrical structures, and finally a spherical axionic condensate. By varying $G$, we show that there are first-order phase transitions, as the system goes from one of these structures to the next one; we find hysteresis loops that are associated with these transitions. We examine these states and the transitions between these states via the Fourier truncated cq-GPPE; and we also obtain the thermalized $T>0$ states from the cq-SGLPE; the transitions between these states yield thermally driven first-order phase transitions and their associated hysteresis loops. Finally, we discuss how our cq-GPPE approach can be used to follow the spatiotemporal evolution of a rotating axionic condensate and also a rotating binary-axionic-condensate system; in particular, we demonstrate, in the former, the emergence of vortices at large angular speeds $\mathrm{\Omega }$ and, in the latter, the rich dynamics of the mergers of the components of this binary system, which can yield vortices in the process of merging.

Different types of phase transition from hadron to quark at high density near zero temperature may occur in the inner core of hybrid stars. We investigate the impacts of phase transition types and quark models on properties of hybrid star and quark cores. The quark-meson coupling (QMC) model is used to describe hadronic matter, and the MIT bag model as well as the Nambu-Jona-Lasinio (NJL) model are employed to describe quark matter for comparison. From the mass-radius curves obtained by using equations of state (EOS), we find that EOSs of hadron matter have a decisive influence on the maximum mass of a hybrid star in the first-order phase transition case, while quark matter EOSs have more impacts on results in the crossover transition case. It is also found in the present work that the thermodynamic correction arising from an interpolation scheme considerably stiffens the EOSs. Therefore the crossover type phase transition generally leads to hybrid stars with higher masses. In particular, by using the QMC model and the NJL model to construct crossover EOSs with thermodynamic correction, we discover that the maximum masses of hybrid stars can meet the recent observational constraint on mass from PSR J0952-0607, i.e., $2.35\pm 0.17M_{\odot }$.

The flux of high-energy astrophysical neutrinos observed by the present generation of neutrino detectors has already indicated a few hints of new physics beyond the Standard Model. In this work, we show that high-energy gamma-ray observations can also be considered as a complementary probe for unveiling the source of high-energy astrophysical neutrino events and new physics. Recently, the LHAASO collaboration has reported $\mathcal{O}(5000)$ gamma-ray events in the energy range between 0.5–18 TeV from gamma-ray burst GRB 221009A within 2000 seconds after the initial outburst. We showed that some of the high-energy gamma rays can be produced from the interaction of astrophysical neutrinos with CMB neutrinos through nonstandard self-interaction of neutrinos mediated by light scalar bosons. The nonstandard interaction of neutrinos recently took a lot of attention in cosmology for its role in reducing Hubble tension. We have constrained the parameter space of nonstandard self-interacting neutrinos from the flux of photons observed by LHAASO and showed consistency of the same with the resulting parameter space from Hubble tension requirements and other recent constraints from laboratory/cosmology.

We discuss the discovery potential of the Dark-photons & Axion-Like particles Interferometer in this paper. The apparatus, currently in a design and prototyping phase, will probe axion dark matter from the Teide Observatory, an environment protected from terrestrial microwave sources, reaching Dine-Fischler-Srednicki-Zhitnitsky-like axion sensitivity in the range $25–250\mathrm{\mu }\mathrm{eV}$ of mass. The experimental approach shows a potential to probe dark sector photons of kinetic mixing strength in excess of several ${10}^{-16}$ and to establish new constraints to a stochastic gravitational wave background in its band. We identify different branches, including cosmology, stellar, and particle physics, where this next-generation halo-telescope may play a role in coming years.