We analyze the time evolution of several physical observables, namely the pressure anisotropy, the scalar condensate, the charge density, and also, for the first time, the nonequilibrium entropy for a Bjorken expanding strongly coupled $\mathcal{N}=4$ supersymmetric Yang-Mills plasma charged under an Abelian $U(1)$ subgroup of the global $SU(4)$ $R$ symmetry. This represents a far-from-equilibrium, hot and dense strongly coupled quantum fluid with a critical point in its phase diagram. For some sets of initial data preserving all the energy conditions, dynamically driven transient violations of the dominant and the weak energy conditions are observed when the plasma is still far from the hydrodynamic regime. The energy conditions violations get stronger at larger values of the chemical potential to temperature ratio, $\mu /T$, indicating that those violations become more relevant as the strongly coupled quantum fluid approaches its critical regime. For some of those energy conditions violations, a clear correlation with different plateau structures formed in the far from equilibrium entropy is observed, indicating the presence of transient, early time windows where the Bjorken expanding plasma has zero entropy production even while being far from equilibrium. The hydrodynamization of the pressure anisotropy and also the much later thermalization of the scalar condensate are generally found to be delayed, within small relative tolerances, as $\mu /T$ is increased toward criticality. The value of $\mu /T$ in the medium is enhanced by increasing its initial charge density and/or also by reducing its initial energy density.

The phase diagram of QCD is investigated by varying number of colors $N_c$ within a Polyakov loop quark-meson chiral model. In particular, our attention is focused on the critical point(s); the critical point present for $N_c=3$ moves toward the ${\mu }_q$-axis and disappears as soon as the number of color is increased. Yet, a distinct critical point emerges along the temperature axis for $N_c=53$ and moves toward finite density when increasing $N_c$ further. Thus, the phase diagram at large $N_c$ looks specular with respect to the $N_c=3$ results, with the first-order transition in the upper-left and crossover in the lower-right regions of the $({\mu }_q,T)$-plane. The pressure is also evaluated in dependence of $N_c$, showing a scaling with $N_c^0$ in the confined and chirally broken phase and with $N_c^2$ in the deconfined one. Moreover, the presence of a chirally symmetric but confined “quarkyonic phase” at large density and moderate temperature with a pressure proportional to $N_c$ is confirmed.

We derive exact analytic solutions for density and velocity fields to all orders in Eulerian standard perturbation theory for $\mathrm{\Lambda }\mathrm{CDM}$ cosmology. In particular, we show that density- and velocity-field kernels can be written in a separable form in time and momenta at each perturbative order. The kernel solutions are built from an analytic basis of momentum operators and their time-dependent coefficients, which solve a set of recursive differential equations. We also provide an exact closed perturbative solution for such coefficients, expanding around the (quasi-)Einstein–de Sitter (EdS) approximation. We find that the perturbative solution rapidly converges towards the numerically obtained solutions and its leading-order result suffices for any practical requirements. To illustrate our findings, we compute the exact two-loop dark matter density- and velocity power spectra in $\mathrm{\Lambda }\mathrm{CDM}$ cosmology. We show that the difference between the exact $\mathrm{\Lambda }\mathrm{CDM}$ and the (quasi-)EdS approximated result can reach the level of several percent (at redshift zero, for wave numbers $k<1h/\mathrm{Mpc}$). This deviation can be partially mitigated by exploiting the degeneracy with the effective field theory counterterms. As an additional benefit of our algorithm for the solutions of time-dependent coefficients, the computational complexity of power-spectra loops in $\mathrm{\Lambda }\mathrm{CDM}$ is comparable to the EdS case. In performing the two-loop computation, we devise an explicit method to implement the so-called IR cancellations, as well as the cancellations arising as a consequence of mass and momentum conservation.

Superconducting nanowires, a mature technology originally developed for quantum sensing, can be used as a target and sensor with which to search for dark matter interactions with electrons. Here we report on a 180-hour measurement of a tungsten silicide superconducting nanowire device with a mass of 4.3 nanograms. We use this to place new constraints on dark matter–electron interactions, including the strongest terrestrial constraints to date on sub-MeV (sub-eV) dark matter that interacts with electrons via scattering (absorption) processes.

At zero temperature and finite chemical potential, $d$-dimensional loop integrals with complex-valued integrands in the imaginary-time formalism yield results dependent on the integration order. We observe this even with the simplest one-loop dimensionally regularized integrals. Computing such integrals by evaluating the spatial ${\mathrm{d}}^{d}p$ integral before the temporal $\mathrm{d}{p}_0$ integral yields results consistent with those obtained at small but nonvanishing temperatures. Computing the temporal integral first by applying the residue theorem to the integrand yields a different answer. The same holds for general complexified propagators. In this work we aim to understand the theoretical background behind this difference, in order to fully enable the powerful techniques of residue calculus in applications. We cast the difference into the form of a derivative term related to Dirac deltas, and further demonstrate how the difference originates from the zero-temperature limit of the Fermi–Dirac occupation functions treated as complex-valued functions. We also discuss a generalization to propagators raised to noninteger powers.

In the gravitational collapse of matter beyond spherical symmetry, gravitational waves are necessarily present. On the other hand, gravitational waves can collapse to a black hole even without matter. One might therefore wonder how the interaction and competition between the matter fields and gravitational waves affects critical phenomena at the threshold of black hole formation. As a toy model for this, we study the threshold of black-hole formation in $4+1$ dimensions, where we add a massless minimally coupled scalar matter field to the gravitational wave ansatz of Bizón, Chmaj, and Schmidt (in a nutshell, Bianchi IX on $S^3\times \text{radius}\times \mathrm{time}$). In order to find a stable discretization of the equation governing the gravitational waves in $4+1$ physical dimensions, which has the same principal part as the spherical wave equation in $9+1$ dimensions, we first revisit the problem of critical spherical scalar field collapse in $n+2$ dimensions with large $n$. Returning to the main problem, we find numerically that weak gravitational wave perturbations of the scalar field critical solution decay, while weak scalar perturbations of the gravitational wave critical solution also decay. A dynamical systems picture then suggests the existence of a codimension-2 attractor. We find numerical evidence for this attractor by evolving mixed initial data and fine-tuning both an overall amplitude and the relative strength of the two fields.

Control over quantum electrodynamics (QED) radiative corrections is critical for precise determination of neutrino oscillation probabilities from observed (anti)neutrino detection rates. It is particularly important to understand any difference between such corrections for different flavors of (anti)neutrinos in charged-current interactions. We provide theoretical foundations for calculating these corrections. Using effective field theory, the corrections are shown to factorize into soft, collinear, and hard functions. The soft and collinear functions contain large logarithms in perturbation theory but are computable from QED. The hard function parametrizes hadronic structure but is free from large logarithms. Using a simple model for the hard function, we investigate the numerical impact of QED corrections in charged-current (anti)neutrino-nucleon elastic cross sections and cross-section ratios at GeV energies. We consider the implications of mass singularity theorems that govern the lepton-mass dependence of cross sections for sufficiently inclusive observables and demonstrate the cancellation of leading hadronic and nuclear corrections in phenomenologically relevant observables.

We introduce an algorithm to piecewise dualize linear quivers into their mirror dual. The algorithm uses two basic duality moves and the properties of the $S$-wall which can all be derived by iterative applications of Seiberg-like dualities.

The peak-patch algorithm is used to identify the densest minicluster seeds in the initial axion density field simulated from string decay. The fate of these dense seeds is found by tracking the subsequent gravitational collapse in cosmological $N$-body simulations. We find that miniclusters at late times are well described by Navarro-Frenk-White profiles, although for around 80% of simulated miniclusters a single power-law density profile of $r^{-2.9}$ is an equally good fit due to the unresolved scale radius. Under the assumption that all miniclusters with an unresolved scale radius are described by a power-law plus axion star density profile, we identify a significant number of miniclusters that might be dense enough to give rise to gravitational microlensing if the axion mass is $0.2\mathrm{meV}\lesssim m_a\lesssim 3\mathrm{meV}$. Higher resolution simulations resolving the inner structure and axion star formation are necessary to explore this possibility further.

We present a reduced-order surrogate model of gravitational waveforms from nonspinning binary black hole systems with comparable to large mass-ratio configurations. This surrogate model, BHPTNRSur1dq1e4, is trained on waveform data generated by point-particle black hole perturbation theory (ppBHPT) with mass ratios varying from 2.5 to 10,000. BHPTNRSur1dq1e4 extends an earlier waveform model, EMRISur1dq1e4, by using an updated transition-to-plunge model, covering longer durations up to $\text{30}\text{,}\text{500}{m}_1$ (where $m_1$ is the mass of the primary black hole), includes several more spherical harmonic modes up to $\ell =10$, and calibrates subdominant modes to numerical relativity (NR) data. In the comparable mass-ratio regime, including mass ratios as low as 2.5, the gravitational waveforms generated through ppBHPT agree surprisingly well with those from NR after this simple calibration step. We also compare our model to recent SXS and RIT NR simulations at mass ratios ranging from 15 to 32, and find the dominant quadrupolar modes agree to better than $\approx {10}^{-3}$. We expect our model to be useful to study intermediate-mass-ratio binary systems in current and future gravitational-wave detectors.

We study the linear polarization from the accretion disk around a class of static traversable wormholes. Applying the simplified model of a magnetized fluid ring orbiting in the equatorial plane, we search for characteristic signatures, which could distinguish wormhole from black hole spacetimes by their polarization properties. For the purpose we analyze the direct polarized images for different inclination angles, the strongly lensed indirect images, and the polarized radiation which reaches the asymptotic observer through the wormhole throat, and compare to the Schwarzschild black hole. For small inclination angles the two types of compact objects lead to a very similar polarization pattern of the direct images. More significant distinctions are observed for the strongly lensed indirect images, where the polarization intensity in the wormhole spacetimes can grow up to an order of magnitude compared to the Schwarzschild black hole. Detecting radiation from the region across the wormhole throat leads to the formation of an additional structure of ring images with distinct polarization properties. The twist of the polarization vector around the ring is less pronounced, thus modifying the polarization pattern, and the polarization intensity can increase with an order of magnitude compared to the radiation from our Universe. Thus, while it could be difficult to distinguish wormhole spacetimes by their direct polarized images, the strongly lensed images and the polarization of the radiation through the wormhole throat provide characteristic signatures which can serve as probes for horizonless objects.

In certain scalar-field extensions to general relativity, scalar charges can develop on compact objects in an inspiraling binary—an effect known as dynamical scalarization. This effect can be modeled using effective-field-theory methods applied to the binary within the post-Newtonian approximation. Past analytic investigations focused on the adiabatic (or quasistationary) case for quasicircular orbits. In this work, we explore the full dynamical evolution around the phase transition to the scalarized regime. This allows for generic (eccentric) orbits and to quantify nonadiabatic (e.g., oscillatory) behavior during the phase transition. We also find that even in the circular-orbit case, the onset of scalarization can only be predicted reliably when taking the full dynamics into account, i.e., the adiabatic approximation is not appropriate. Our results pave the way for accurate post-Newtonian predictions for dynamical scalarization effects in gravitational waves from compact binaries.

We present a new approach to studies of bubble dynamics in fluids. Relying on particle-based simulations, this method is general and suitable for cases where the commonly used perfect fluid description fails. We study expanding true vacuum bubbles surrounded by free or self-interacting particles and quantify how self-interactions affect the terminal bubble wall velocity. We find that, for sufficiently strongly self-interacting fluids, local thermal equilibrium is maintained around the bubble wall and the fluid profile is similar to that obtained with the perfect fluid description.

We examine the effect of neutrino flavor transformation by the fast flavor instability (FFI) on long-term mass ejection from accretion disks formed after neutron star mergers. Neutrino emission and absorption in the disk set the composition of the disk ejecta, which subsequently undergoes $r$-process nucleosynthesis upon expansion and cooling. Here we perform 28 time-dependent, axisymmetric, viscous-hydrodynamic simulations of accretion disks around hypermassive neutron stars (HMNSs) of variable lifetime, using a 3-species neutrino leakage scheme for emission and an annular-lightbulb scheme for absorption. We include neutrino flavor transformation due the FFI in a parametric way, by modifying the absorbed neutrino fluxes and temperatures, allowing for flavor mixing at various levels of flavor equilibration, and also in a way that aims to respect the lepton-number preserving symmetry of the neutrino self-interaction Hamiltonian. We find that for a promptly-formed black hole (BH), the FFI lowers the average electron fraction of the disk outflow due to a decrease in neutrino absorption, driven primarily by a drop in electron neutrino/antineutrino flux upon flavor mixing. For a long-lived HMNS, the disk emits more heavy lepton neutrinos and reabsorbs more electron neutrinos than for a BH, with a smaller drop in flux compensated by a higher neutrino temperature upon flavor mixing. The resulting outflow has a broader electron fraction distribution, a more proton-rich peak, and undergoes stronger radiative driving. Disks with intermediate HMNS lifetimes show results that fall in between these two limits. In most cases, the impact of the FFI on the outflow is moderate, with changes in mass ejection, average velocity, and average electron fraction of order $\sim 10\%$, and changes in the lanthanide/actinide mass fraction of up to a factor $\sim 2$.

Experimental refinements and technical innovations in the field of extensive air shower telescopes have enabled measurements of Galactic cosmic-ray interactions in the sub-PeV range, providing new avenues for the search for new physics and dark matter. For the first time, we exploit sub-PeV (1 TeV–1 PeV) observations of Galactic diffuse gamma rays by HAWC and Tibet $\mathrm{AS}\gamma$ to search for an axionlike-particle (ALP) induced gamma-ray signal directly linked to the origin of the IceCube extragalactic high-energy neutrino flux. Indeed, the production of high-energy neutrinos in extragalactic sources implies the concomitant production of gamma rays at comparable energies. Within the magnetic field of the neutrino emitting sources, gamma rays may efficiently convert into ALPs, escape their host galaxy unattenuated, propagate through intergalactic space, and reconvert into gamma rays in the magnetic field of the Milky Way. Such a scenario creates an all-sky diffuse high-energy gamma-ray signal in the sub-PeV range. Accounting for the guaranteed Galactic astrophysical gamma-ray contributions from cosmic-ray interactions with gas and radiation and from subthreshold sources, we set competitive upper limits on the photon-ALP coupling constant $g_{a\gamma \gamma }$. We find $g_{a\gamma \gamma }<2.1\times {10}^{-11}{\mathrm{GeV}}^{-1}$ for ALP masses $m_a\le 2\times {10}^{-7}\mathrm{eV}$ at a 95% confidence level. Our results are comparable to previous limits on ALPs derived from the TeV gamma-ray domain and progressively close the mass gap toward ADMX limits.

We compute theoretical predictions for the production of a $W$ boson in association with a bottom-quark pair at hadron colliders at next-to-next-to-leading order (NNLO) in QCD, including the leptonic decay of the $W$ boson, while treating the bottom quark as massless. This calculation constitutes the very first $2\to 3$ process with a massive external particle to be studied at such a perturbative order. We derive an analytic expression for the required two-loop five-particle amplitudes in the leading color approximation employing finite-field methods. Numerical results for the cross section and differential distributions are presented for the Large Hadron Collider at $\sqrt{s}=8\mathrm{TeV}$. We observe an improvement of the perturbative convergence for the inclusive case and for the prediction with a jet veto upon the inclusion of the NNLO QCD corrections.

We give a detailed exposition of the formalism of kinetic field theory (KFT) with emphasis on the perturbative determination of observables. KFT is a statistical nonequilibrium classical field theory based on the path integral formulation of classical mechanics, employing the powerful techniques developed in the context of quantum field theory to describe classical systems. Unlike previous work on KFT, we perform the integration over the probability distribution of initial conditions in the very last step. This significantly improves the clarity of the perturbative treatment and allows for physical interpretation of intermediate results. We give an introduction to the general framework, but focus on the application to interacting $N$-body systems. Specializing the results to cosmic structure formation, we reproduce the linear growth of the cosmic density fluctuation power spectrum on all scales from microscopic, Newtonian particle dynamics alone.

We show how to compute classical wave observables using quantum scattering amplitudes. We discuss observables both with incoming and with outgoing waves. The required classical limits are naturally described by coherent states of massless bosons. We recompute the classic gravitational deflection of light, and also show how to rederive Thomson scattering. We introduce a new class of local observables, which includes the asymptotic electromagnetic and gravitational Newman-Penrose scalars. As an example, we compute a simple radiated waveform: the expectation of the electromagnetic field in charged-particle scattering. At leading order, the waveform is trivially related to the five-point scattering amplitude.

We determine the higher symmetries of 5D SCFTs engineered from M-theory on a ${\mathbb{C}}^3/\mathrm{\Gamma }$ background for $\mathrm{\Gamma }$ a finite subgroup of $SU(3)$. This resolves a longstanding question as to how to extract this data when the resulting singularity is nontoric (when $\mathrm{\Gamma }$ is non-Abelian) and/or not isolated (when the action of $\mathrm{\Gamma }$ has fixed loci). The Bogomol’nyi-Prasad-Sommerfield (BPS) states of the theory are encoded in a 1D quiver quantum mechanics gauge theory which determines the possible 1-form and 2-form symmetries. We also show that this same data can also be extracted by a direct computation of the corresponding defect group associated with the orbifold singularity. Both methods agree, and these computations do not rely on the existence of a resolution of the singularity. We also observe that when the geometry faithfully captures the global 0-form symmetry, the abelianization of $\mathrm{\Gamma }$ detects a 2-group structure (when present). As such, this establishes that all of this data is indeed intrinsic to the superconformal fixed point rather than being an emergent property of an IR gauge theory phase.

We discuss how small-scale density perturbations on the Fresnel scale affect amplitudes and phases of gravitational waves that are magnified by gravitational lensing in geometric optics. We derive equations that connect the small-scale density perturbations with the amplitude and phase fluctuations to show that such perturbative wave optics effects are significantly boosted in the presence of macro model magnifications such that amplitude and phase fluctuations can easily be observed for highly magnified gravitational waves. We discuss expected signals due to microlensing by stars, dark matter substructure, fuzzy dark matter, and primordial black holes.