The quantum-field-theoretic description for the U(1)-Goldstone boson of a scalar Bose-Einstein condensate with time-dependent contact interactions is developed beyond the acoustic approximation in accordance with Bogoliubov theory. The resulting effective action is mapped to a relativistic quantum field theory on a dispersive (or rainbow) cosmological spacetime which has a superluminal Corley-Jacobson dispersion relation. Time-dependent changes of the s-wave scattering length to quantum-simulate cosmological particle production are accompanied by a time-dependent healing length that can be interpreted as an analog Planck length in the comoving frame. Nonadiabatic transitions acquire a dispersive character, which is thoroughly discussed. The framework is applied to exponentially expanding or power-law contracting ($2+1$)-dimensional spacetimes which are known to produce scale-invariant cosmological power spectra. The sensitivity of these scenarios to the time dependence of the Bogoliubov dispersion is investigated: We find a violation of scale invariance via analytically trackable trans-Planckian damping effects if the cutoff scale is not well separated from the horizon-crossing scale. In case of the exponential expansion, these damping effects remarkably settle and converge to another scale-invariant plateau in the far ultraviolet regime where nonadiabatic transitions are suppressed by the high dispersion. The developed framework enables quantitative access to more drastic analog cosmological scenarios with improved predictability in the ultraviolet regime that ultimately may lead to the observation of a scale-invariant cosmological power spectrum in the laboratory.

We investigate the high-energy, small-angle limit of two-body gravitational scattering. Using power counting arguments and dispersion relations in an effective field theory for the Regge regime, we derive the general loop expansion that determines how the leading Regge logarithms and their complex structure arise as a power series in $t/s$. Focusing on the tower of multi-H diagrams that govern the leading logarithmic behavior, we compute the leading double logarithm at four loops (or equivalently fifth post-Minkowskian order, 5PM) using both effective field theory methods and the multi-Regge expansion, finding complete agreement. Finally, using the aforementioned dispersion relations, we extract the single logarithmic contribution to the imaginary part of the eikonal phase at 5PM in the Regge limit.

We determine the parametric conditions (pulse strength and duration) under which Schwinger’s prediction for the pair-creation current—and therefore the probability—is significantly altered.

We propose a refinement of the Kontsevich-Soibelman operator for a class of four-dimensional $\mathcal{N}=2$ superconformal field theories characterized by the following conditions: (1) Their Coulomb branch admits a source/sink chamber, i.e., a chamber in which the Bogomol’nyi-Prasad-Sommerfield (BPS) quiver consists of only source and sink nodes. (2) The nodes with valency greater than 2 of the BPS quiver in a source/sink chamber are either all sources or all sinks. We present strong evidence that the trace of this refined operator is related to the Macdonald index of the theory. In particular, we conjecture new closed form expressions for the Macdonald indices of the $(A_1,\mathfrak{g})$ Argyres-Douglas theories for any simply laced Lie algebra $\mathfrak{g}$.

We investigate the effects, stability, and nonlinear dynamics of ghost scalar matter modeled as a field with a negative kinetic term confined within the cores of neutron stars. To this end, we analyze static configurations of the coupled Einstein-Euler (ghost, complex) Klein-Gordon system and then we perform fully dynamical numerical evolutions of illustrative cases. Our results demonstrate that neutron stars can gravitationally confine a finite amount of ghost matter and support continuous families of equilibrium solutions, indicating that these configurations are not the result of fine tuning. We analyze the properties of the final states and find that the neutron star undergoes a persistent pulselike oscillatory motion. In particular, we explicitly compute the frequency synchronization between the stellar fluid oscillation modes and those of the ghost scalar sector.

We explore the thermodynamic and entanglement properties of dynamical black holes based on the recently proposed dynamical black hole entropy by Hollands-Wald-Zhang. We first provide direct proof that, under first-order perturbations, the dynamical black hole entropy in any $f(R)$ theory equals the Wald entropy evaluated on the generalized apparent horizon. Then, we compute the gravitational entropy explicitly from the replica method using both the event horizon and the apparent horizon as the entangling surfaces, and we show that only the apparent horizon prescription reproduces the correct dynamical black hole entropy satisfying the physical process first law. Furthermore, we reinterpret the generalized second law by identifying the modified von Neumann entropy as the matter entanglement across the (generalized) apparent horizon. This allows us to express the total entropy as the renormalized generalized entropy evaluated on this surface at the level of the leading local area-law term.

We show that axions can be produced from Abelian-Higgs cosmic strings due to the axion-gauge coupling. The strong magnetic field is confined in the string, and the electric field is induced around the moving string, allowing axion productions from the dynamics of cosmic strings. Our numerical analysis on the string collision shows that a sizable number of axions can be produced at the reconnection, and further emissions occur from moving kinks afterward. Large-scale lattice simulations of the string network further reveal multimodal axion emissions in the sense that axions are produced in both the low-energy and high-energy regimes. The former can contribute to the cold dark matter and the latter can be regarded as dark radiation. We found that the axion with GeV or heavier mass can explain the current relic dark matter abundance and simultaneously predicts a sizable amount of dark radiation which can be probed by future observations.

The empirical correlation between the $\mathrm{H}\beta$ luminosity ($L$) and the ionized gas velocity dispersion ($\sigma$) in HII starburst galaxies (HIIGs) provides a foundation for using them as cosmological standard candles. A key unresolved issue is whether this $L-\sigma$ relation changes with redshift, which would impact its application at high redshifts. We test for possible evolution using cosmology-independent distance estimates up to $z\sim 1.8$, obtained from Gaussian process regression of the $\mathrm{Pantheon}+\mathrm{type}$ Ia supernovae Hubble diagram. These distances allow us to compare the standard $L-\sigma$ relation with three redshift-dependent extensions through Bayesian model comparison. We find that a logarithmic redshift correction is statistically preferred when the intrinsic dispersion of the relation is explicitly modeled, significantly improving the fit to high-$z$ data. However, the evidence for evolution strongly depends on how the likelihood function accounts for this intrinsic dispersion and is weaker if it is ignored. We also show that Malmquist bias significantly affects comparisons between low- and high-$z$ samples, reducing—though not eliminating—the statistical preference for redshift evolution after matching luminosity ranges. These results indicate that current HIIG data favor a redshift-dependent modification of the standard $L-\sigma$ relation, while highlighting the critical role of selection effects and intrinsic dispersion modeling in establishing HIIGs as precise cosmological probes.

Magnetic fields play a central role in black hole astrophysics, powering relativistic jets and other energetic phenomena. While near-horizon magnetic field is usually assumed to originate from the accretion flow, additional large-scale magnetic fields—such as those supplied by a companion neutron star in stellar-mass binaries or by galactic fields around supermassive black holes—may also affect the horizon-threading flux. In this work, we study the superposition of a weak arbitrarily inclined external uniform magnetic field with the internal Blandford–Znajek split-monopole field around a Schwarzschild black hole. This setup generically gives rise to magnetic null points, where the total field vanishes. We compute the magnetic flux through an arbitrarily tilted hemisphere of the event horizon and show that the flux can be substantially suppressed by the external field. In the axisymmetric case, the flux can even vanish completely. However, with nonzero inclination, complete cancellation becomes impossible, despite significant reduction. We further explore the ionization and subsequent particle acceleration from a Keplerian accretion disk, finding that efficient collimated outflows persist even under significant field inclination. We show that the acceleration is critically dependent on the external field orientation, with the escape fraction maximized at nonzero inclinations due to the destabilization of trapping zones and vanishing in the antialigned configuration, where closed magnetic loops effectively suppress the outflow. We discuss the astrophysical implications of these findings, proposing that geometric flux cancellation can serve as a mechanism for jet quenching in compact binaries and offering an explanation for the lack of a prominent large-scale jet in Sgr A*.

Many pulsars exhibit a peculiar behavior in their pulse profile of a sudden increase in their rotational period, which is popularly known as a pulsar glitch. Some of them show giant glitches with relative amplitude $\mathrm{\Delta }\mathrm{\Omega }/\mathrm{\Omega }\sim {10}^{-6}–{10}^{-5}$. With the model of pinned neutron vortices inside the neutron star crust, this large glitch cannot be explained so far. However, the increasing evidence of massive pulsars indicates the appearance of exotic degrees of freedom in the inner core of the pulsars. Given this, we consider the pulsar as a hybrid star. This model opens up the possibility of vortex-pinning inside the core. Under the Gibbs equilibrium conditions, it is possible for hadrons and the quark phase to coexist. Due to the global charge neutrality condition, quark pasta structures are formed in the background of hadronic matter. We consider these pasta structures as pinning sites of superfluid vortices. We show that considering the core contribution, our calculations come to be of the order of $\mathrm{\Delta }\mathrm{\Omega }/\mathrm{\Omega }\sim {10}^{-6}$, which is close to the observations shown by the Vela-like pulsars.

Scintillating Bubble Chamber collaboration is searching for weakly interacting massive particles using a novel bubble chamber with intended thresholds as low as 100 eV. Existing molecular dynamics simulations of bubble formation in bubble chambers were conducted with nonscintillating target materials and therefore do not account for the energy transfer to photons or time-delayed releases that occur in atomic de-excitation. In this study, we use the HOOMD-blue molecular dynamics framework to simulate bubble formation in liquid argon, including photon creation, ionization, and direct nuclear recoils. A multistage bubble growth process similar to that reported in the literature was observed. When comparing simulated thresholds with and without scintillation effects, we found that scintillation raises the average energy required to form a bubble by a factor of 2.16. This is larger than the fraction of energy lost to photon creation and demonstrates that energy stored in excited molecular states with lifetimes longer than the rapid growth phase of nucleation ($\sim 250\mathrm{ps}$) does not contribute significantly to bubble formation. This conclusion was further supported by simulations showing increased bubble nucleation thresholds when the excited molecular state lifetimes were increased, even under identical thermodynamic conditions.

We present an efficient numerical algorithm for evolving self-gravitating systems of dark-matter particles that leverages the assumption of spherical symmetry to reduce the nominally six-dimensional phase space to three dimensions. It can be used to quickly determine numerically the evolution of an initially static stable self-consistent self-gravitating system if there is some additional or new physics. We illustrate here with four examples: (1) the effects of the growth of a supermassive black hole at the center; (2) the effects of stripping of the outer layers of the halo (a toy model for the effects of tidal stripping of galaxies); (3) the response of a self-gravitating system to dark matter that decays to a slightly less massive state; and (4) the effects of a slow change to Newton’s constant. The approach can be extended to study dark matter with elastic and inelastic self-interactions and to study the process of virialization in spherical collapse. We describe some aspects of a code, nsphere, that implements this approach.

Next-generation gravitational-wave detectors such as Cosmic Explorer and the Einstein Telescope will operate 10–40 km Fabry-Pérot arm cavities inside vacuum beam tubes. FFT-based paraxial tools treat propagation in free space and therefore do not explicitly enforce beam tube boundary conditions. We introduce a waveguidelike mode description of the optical field that incorporates an imposed beam tube boundary condition and enables an independent benchmark of free-space FFT tools. We derive the associated modal-mixing matrices for mirrors and baffles, including a closed-form series for axisymmetric circular apertures. We quantify the strain-equivalent couplings from baffle miscentering and from a localized near-wall tube defect, and show that they are suppressed as baffle density increases. In the relevant regime of densely baffled cavities and small perturbations, beam tube boundary effects are subdominant, which supports the continued use of FFT-based codes to guide the design of third generation detectors.

We construct an effective light-front mass-squared operator for quark-antiquark systems that incorporates quark dressing effects through a running quark mass. Starting from a Minkowski-space quark propagator constrained by lattice-QCD–inspired parametrization, we derive the disconnected light-front resolvent for a light quark-antiquark system using a generalized spectral representation of an individual quark propagator separating out the instantaneous contributions. By projecting the resolvent onto a constituent-quark helicity basis, we obtain an effective dressed mass-squared operator suitable for light-front Hamiltonian approaches. We introduce an effective light-front quark self-energy and analyze its momentum dependence. As an application, we study pion structure using representative light-front wave-function models and compute unpolarized transverse-momentum–dependent distributions, unpolarized parton distribution functions, and distribution amplitudes. Our results show that quark dressing induces sizable infrared modifications while preserving controlled ultraviolet behavior, providing a framework to incorporate nonperturbative QCD dynamics into light-front descriptions of hadrons.

We assess the accuracy of our previous asymptotic Padé predictions of the five-loop QCD $\beta$-function and quark mass anomalous dimension in the light of subsequent exact results. We find the low-order coefficients in an expansion in powers of $N_F$ (the number of flavors) were correct to within 1%. Furthermore an examination of recent results in $\lambda {\varphi }^4$ theory indicates that the asymptotic Padé methods deliver predictions which increase in accuracy with loop order. Encouraged by this, we present six-loop asymptotic Padé predictions for the QCD $\beta$-function and quark mass anomalous dimension and also for the eight-loop $\beta$-function in $O(N)$ $\lambda {\varphi }^4$ theory.

The effects of polarization transfer from the initial electron to the bremsstrahlung photon in electron-nucleus scattering (Bethe-Heitler process) are considered. The calculation is carried out without the assumption of smallness of the electron mass. A detailed comparison with previous well-known works is made. Some issues related to neglecting the electron mass are shown and commented on. The results are applicable to the modeling of polarized cross sections at energies down to the electron mass scale.

In the Standard Model, partial unification of the non-Abelian running gauge couplings is achieved at the scale ${\mu }_{32}^{\mathrm{SM}}\approx 2.8\times {10}^{16}\mathrm{GeV}$. Elaborating on this fact, we discuss a simple general parametrization for the new physics corrections leading to full unification at some scale $M_X$. We show that for any new physics model such that the corrections to the non-Abelian couplings are equal (or nearly so), $M_X$ is equal (or close to) the partial unification scale ${\mu }_{32}^{\mathrm{SM}}$; the latter scales could be disentangled only if the corrections to the non-Abelian couplings are significantly different. We explore how the parametrization works for some relevant models with new physics below $M_X$, as low-energy supersymmetry, split supersymmetry, etc. As for models with a desert up to $M_X$, we explore, in particular, how the parametrization works for string-inspired corrections; we find a phenomenologically remarkable possibility for unification at about 100 TeV, suggesting a low string scale, in addition to the more conservative possibility for unification at ${\mu }_{32}^{\mathrm{SM}}$; for models with power-law running/threshold corrections, we also outline an interesting connection with the number of fermion families propagating in the bulk.

Gravitational effects are known to violate global symmetries, threatening the Peccei-Quinn solution to the strong $CP$ problem. Ultraviolet completions featuring a gauged $U(1)$ symmetry, where $U(1{)}_{\mathrm{PQ}}$ arises as an accidental global symmetry, can suppress Planck-suppressed operators, enabling high-quality axions in a mass window where it can also account for the observed dark matter (DM) in the Universe. We show that in such models, the spontaneous breaking of the $U(1)$ gauge symmetry generates a strong stochastic gravitational wave background (SGWB) from gauge cosmic string loops. Even in the most conservative scenario, for breaking scales $\gtrsim {10}^{14}\mathrm{GeV}$, the SGWB signal strength can exceed astrophysical foregrounds across a broad frequency range. Such quality axion models have a characteristic IR break frequency originating from the dynamics of the string-wall network collapse. We propose this characteristic SGWB frequency-amplitude region, identified as signature-window-axion-gravitational waves (SWAG), to be a novel probe of high-quality axion DM at future space and ground-based interferometers.

Strongly supercooled first-order phase transitions have been proposed as a primordial black hole (PBH) production mechanism. While previous works rely on simplified models with limited thermodynamic precision, we stress that reliable theoretical PBH predictions require precise nucleation dynamics within realistic extensions of the Standard Model. By employing high-temperature dimensional reduction and computing the one-loop fluctuation determinants, we provide a state-of-the-art thermodynamic analysis and obtain a universal lower bound on the transition timescale, $\beta /H_{*}\simeq 5$. Then, we estimate the corresponding PBH abundance for classically conformal gauge-Higgs theories. Accounting for constraints from successful percolation and QCD chiral symmetry breaking, the parameter space where PBHs are viable dark matter candidates is severely limited.

An extension of the standard model with ${\mathrm{\Gamma }}_2\simeq S_3$ modular flavor symmetry is presented. We consider the construction of the lepton sector, augmented by two right-handed neutrino states, in the vicinity of the fixed points $\tau =i\infty$, $\tau =i$, and $\tau =\omega =-\frac{1}{2}+i\frac{\sqrt{3}}{2}$. Due to the residual symmetries at these points, and with the aid of nonholomorphic modular forms (which constitute representations of $S_3$) and by assigning specific transformation properties to the fermion fields, highly economical models (without flavon fields) are constructed with interesting Yukawa textures. All presented models strongly prefer the inverted ordering for the neutrino masses.