During slow-roll inflation, nonperturbative transitions can produce bubbles of metastable vacuum. These bubbles expand exponentially during inflation to superhorizon size, and later collapse into black holes when the expansion of the Universe is decelerating. Estimating the rate for these transitions during a time-dependent slow-roll phase requires the development of new techniques. Our results show that in a broad class of models, the inflationary fine-tuning that gives rise to small density fluctuations causes these bubbles to appear only during a time interval that is short compared to the inflationary Hubble time. As a result, despite the fact that the final mass of the black hole is exponentially sensitive to the moment bubbles form during inflation, the resulting primordial black hole mass spectrum can be nearly monochromatic. If the transition occurs near the middle of inflation, the mass can fall in the “asteroid” range ${10}^{17}–{10}^{22}\mathrm{g}$ in which all known observations are compatible with black holes comprising 100% of dark matter.

We propose a geometrical origin for the Shibata-Sasaki compaction function, which is known to be a reliable indicator of primordial black hole formation at least during radiation domination. In the long-wavelength limit, we identify it with a compactness function in the static spacetime obtained by removing the cosmological scale factor from the metric and this explains why it cannot be greater than $1/2$. If its maximum is below $1/2$, the perturbation is of type I. If its maximum equals $1/2$, it corresponds to an extremal surface, which is simultaneously a bifurcating trapping horizon and admits a circular photon orbit in the static spacetime. In the long-wavelength regime of the physical expanding Universe, the Shibata-Sasaki compaction reaches its maximum value of $1/2$ at maximal and minimal surfaces on the constant time spacelike hypersurface, which feature a type II perturbation and both correspond to photon spheres expanding along with the cosmological expansion. Thus, the Shibata-Sasaki compaction measures how close to the type II configuration the perturbed region is.

In astrophysical environments such as core-collapse supernovae (CCSNe) and binary neutron star mergers (BNSMs), neutrinos potentially experience substantial flavor mixing due to the refractive effects of neutrino self-interactions. Determining the survival probability of neutrinos in asymptotic states is paramount to incorporating flavor conversions’ effects in the theoretical modeling of CCSN and BNSM. Some phenomenological schemes have shown good performance in approximating asymptotic states of fast neutrino-flavor conversions (FFCs), known as one of the collective neutrino oscillation modes induced by neutrino self-interactions. However, a recent study showed that they would yield qualitatively different asymptotic states of FFC if the neutrino number is forced to evolve. It is not yet fully understood why the canonical phenomenological models fail to predict asymptotic states. In this paper, we perform detailed investigations through numerical simulations and then provide an intuitive explanation with a quasihomogeneous analysis. Based on the analysis, we propose a new phenomenological model, in which the quasisteady evolution of FFCs is analytically determined. The model also allows us to express the convolution term of spatial wave number as a concise form, which corresponds to useful information on analyses for the nonlinear feedback from small-scale flavor conversions to large-scale ones. Our model yields excellent agreement with numerical simulations, which lends support to our interpretation.

We investigate the possibility that primordial black holes (PBHs) can be formed from large curvature perturbations generated during the waterfall phase transition in a supersymmetric scenario where sneutrino is the inflaton in a hybrid inflationary framework. We obtain a spectral index ($n_s\simeq 0.966$), and a tensor-to-scalar ratio ($r\simeq 0.0056–{10}^{-11}$), consistent with the current Planck data satisfying PBH as dark matter (DM) and detectable gravitational wave (GW) signal. Our findings show that the mass of PBH and the peak in the GW spectrum is correlated with the right-handed (s)neutrino mass. We identify parameter space where PBHs can be the entire DM candidate of the Universe (with mass ${10}^{-13}{M}_{\odot }$) or a fraction of it. This can be tested in future observatories, for example, with amplitude ${\mathrm{\Omega }}_{\mathrm{GW}}{h}^2\sim {10}^{-9}$ and peak frequency $f\sim 0.1\mathrm{Hz}$ in LISA and ${\mathrm{\Omega }}_{\mathrm{GW}}{h}^2\sim {10}^{-11}$ and peak frequency of $\sim 10\mathrm{Hz}$ in Einstein Telescope via second-order GW signals. We study two models of sneutrino inflation: Model-1 involves the canonical sneutrino kinetic term, which predicts the sub-Planckian mass parameter $M$, while the coupling between a gauge singlet and the waterfall field, $\beta$, needs to be quite large whereas, for the model-2 involving the $\alpha$-attractor canonical sneutrino kinetic term, $\beta$ can take a natural value. Estimating explicitly, we show that both models have mild fine-tuning. We also derive an analytical expression for the power spectrum in terms of the microphysics parameters of the model like (s)neutrino mass, etc. that fits well with the numerical results. The typical reheat temperature for both the models is around ${10}^7–{10}^8\mathrm{GeV}$ suitable for nonthermal leptogenesis.

We present a novel unified approach to describe the dense symmetric nuclear matter by combining the quarkyonic matter framework with the parity doublet model. This integration allows for a consistent treatment of the transition from hadronic to quark degrees of freedom while incorporating chiral symmetry restoration effects. Our model introduces a chiral invariant mass for both baryons and constituent quarks, enabling a smooth crossover between hadronic and quark matter in symmetric nuclear matter. We derive the equation of state (EOS) for this hybrid system and investigate its thermodynamic properties. The model predicts a gradual onset of quark degrees of freedom at high densities while maintaining aspects of confinement. Furthermore, we find that the resultant EOS is stiffer than that obtained in the previous analysis where the constant mass is used.

In the framework of the minimal supersymmetric model extension with new scalar triplets and singlet (TNMSSM), we analyze the electric dipole moment (EDM) of neutrons ($d_n$), electrons EDM($d_e$), mercury EDM($d_{Hg}$), and $b$ quarks ($d_b$) and $c$ quarks ($d_c$) by considering the contributions from the one-loop diagrams, some two-loop diagrams, and the Weinberg operators. The effects of TNMSSM specific $CP$-violating sources ${\chi }_d$, ${\chi }_t$ on $d_n$, $d_e$, $d_{Hg}$, $d_b$, and $d_c$ are specialized; it is found that they have significant contributions to these EDMs, and the current upper bounds on $d_n$ impose strict constraints on ${\chi }_d$, ${\chi }_t$. The theoretical predictions on $d_b$, $d_c$ can reach about ${10}^{-22}\mathrm{e}·\mathrm{cm}$ and ${10}^{-23}\mathrm{e}·\mathrm{cm}$ respectively by taking the upper bounds on $d_n$, $d_e$, and $d_{Hg}$ into account, which have great potential to be observed in the future.

A model for the Lorentz- and $CPT$-violating frequency shift for the antihydrogen $1S\text{−}2P$ transition in the presence of an external magnetic field is derived. Using the recent measurement of the $1S\text{−}2P$ transition frequency in antihydrogen by the ALPHA collaboration, which they demonstrated agrees with predictions from the Standard Model of particle physics, we establish the first constraints on 26 effective coefficients for Lorentz and $CPT$ violation. Also, this work uses these results to underscore the value of measuring multiple transition frequencies to test $CPT$ symmetry through antihydrogen spectroscopy, emphasizing the advantages of transitions involving states with higher angular momentum.

Universal theories are a broad class of well-motivated microscopic dynamics of the electroweak sector that go beyond the Standard Model description. The long distance physics is described by electroweak parameters which correspond to local operators in the effective field theory. We show how unitarity and analyticity constrain the space of parameters. In particular, the $W$ and $Y$ parameters are constrained to be positive and are necessarily the leading terms in the low-energy expansion. We assess the impact of unitarity on the interpretation of Drell-Yan data. In passing, we uncover an unexpected Wilson coefficient transcendental cancellation at the $\mathcal{O}(<{10}^{-3})$ level.

${\mathbb{Z}}_3$ lattice gauge theory is the simplest discrete gauge theory with three-quark bound states, i.e., baryons. Since it has a finite-dimensional Hilbert space, it can be used for testing quantum simulation of lattice gauge theory at nonzero baryon density. We discuss global and local gauge symmetries and their importance in quantum simulation. We perform quantum emulator calculation and demonstrate how to study the ground state property of baryonic matter.

In this paper, our aim is to illustrate that the process of open string scattering corresponds to the evolution of the entanglement wedge, where the scattering distance is identified as the entanglement wedge cross section. Moreover, open-closed string scattering, specifically the disk-disk interaction, works for the evolution of the reflected entanglement wedge, with the circumference of the waist cross section equating to the reflected entropy. It therefore provides evidence for the deep connections between the string world sheet and the Ryu-Takayanagi surface. This connection is not only a coincidence rooted in hyperbolic geometry; it also reflects an additional correspondence between two distinct theories: mutual information and the geometric Batalin-Vilkoviski master equation.

We study the influence of a rotation on the string tension and the temperature of the confinement-deconfinement phase transition of gluodynamics by gauge/gravity duality. We explore two distinct approaches, global transformation and local transformation, to introduce rotation and compare the results. It is shown that the string tension extracted from the free energy in the presence of a heavy quarkonium decreases with increasing angular velocity, while the transition temperature determined by the Polyakov loop increases with increasing angular velocity, which is in line with lattice simulations.

Gravitational lensing offers a powerful tool for exploring the matter distribution in the Universe. Thanks to their low frequencies and phase coherence, gravitational waves (GWs) allow for the observation of novel wave-optics features (WOFs) in lensing, inaccessible to electromagnetic signals. Combined with the existing accurate source models, lensed GWs can be used to infer the properties of gravitational lenses. The prospect is particularly compelling for space-borne detectors, where the high signal-to-noise ratio expected from massive black hole binary mergers allows WOFs to be distinguished deep into the weak lensing regime, drastically increasing the detection probability. Here, we investigate in detail the capacity of the LISA mission to detect WOFs caused by dark matter halos, galaxies, and the supermassive black holes (SMBHs) within them. We estimate the total optical depth to be ${\lambda }_{\mathrm{tot}}\sim 6\times {10}^{-3}$ for the loudest binaries of total mass $M_{\mathrm{BBH}}\sim {10}^6{M}_{\odot }$, with the dominant contribution coming from SMBHs. We also find that WOFs in low-mass binaries $M_{\mathrm{BBH}}\sim {10}^4{M}_{\odot }$ are more likely due to the central galaxies. Within our model of gravitational lenses, we predict $\mathcal{O}(0.1)-\mathcal{O}(1)$ weakly lensed events to be detectable during the five years of LISA mission, depending on the source population models. We show that WOFs signatures are very sensitive to the properties of dark matter halos with $M_{\mathrm{vir}}\in ({10}^6–{10}^8)M_{\odot }$: Increasing the compactness parameter by $\sim 3$ in that range raises the detection rate by $\sim 26$. Additionally, we show that collective effects from the complex inner halo structure can further enhance detectability. This suggests that lensed GWs in LISA will be an excellent probe of dark-matter theories, baryonic, and halo substructures.

The Laser Interferometer Space Antenna data stream will contain gaps with missing or unusable data due to antenna repointing, orbital corrections, instrument malfunctions, and unknown random processes. We introduce a new deep learning model to impute data gaps in the Laser Interferometer Space Antenna data stream. The stacked hybrid autoencoder combines a denoising convolutional autoencoder with a bidirectional gated recurrent unit. The denoising convolutional autoencoder is used to extract relevant features in the corrupted data, while the bidirectional gated recurrent unit captures the temporal dynamics of the gravitational-wave signals. We show for a massive black hole binary signal, corrupted by data gaps of various numbers and duration, that we yield an overlap of greater than 99.97% when the gaps do not occur in the merging phase and greater than 99% when the gaps do occur in the merging phase. However, if data gaps occur during merger time, we show that we get biased astrophysical parameter estimates, highlighting the need for “protected periods,” where antenna repointing does not occur during the predicted merger time.

Relativistic causality constrains the $S$-matrix both through its analyticity, and by imposing lower bounds on the scattering time delay. These bounds are easiest to determine for spacetimes which admit either a timelike or null Killing vector. We revisit a class of pp-wave spacetimes and carefully determine the scattering time delay for arbitrary incoming states in the eikonal, semiclassical, and Born approximations. We apply this to the effective field theory of gravity in arbitrary dimensions. It is well-known that higher-dimension operators such as the Gauss-Bonnet term, when treated perturbatively at low energies, can appear to make both positive and negative contributions to the time delays of the background geometry. We show that even when multiple shockwaves are stacked, the corrections to the scattering time delay relative to the background are generically unresolvable within the regime of validity of the effective field theory so long as the Wilson coefficients are of order unity. Phrased the other way, this can be read as a bound on the Wilson coefficient from infrared causality which are consistent with positivity/bootstrap bounds.

Using Euclidean methods we investigate the thermodynamics of stealth black hole solutions, which are solutions that geometrically are indistinguishable from those of general relativity; however, they are accompanied by a nontrivial additional field that does not backreact to the metric. We find that in general, one can observe shifts in the mass and/or the entropy of such black holes; hence, at least at the thermodynamic level, the stealth solutions may be distinguished by those of general relativity. We also point out an example, the bona fide stealth, where a nontrivial scalar field can accompany an (A)dS-Schwarzschild black hole without altering the thermodynamic quantities. We point out that thermodynamic discrepancies arise due to the additional boundary terms emanating from the stealth fields, where care should be given in order for the theory at hand to possess a well-defined variational procedure.

An axionlike spectator during inflation can trigger a tachyonic instability which amplifies the modes of one of the helicities of the gauge field, resulting in the production of parity-violating gravitational waves (GWs). In this paper we investigate the impact of the coupling $RFF$ of the gauge field to gravity on the production of GWs. We find that such a coupling introduces a multiplicative factor to the tachyonic mass, which effectively enhances the amplitude of the gauge field modes. Produced GWs are expected to be observed by future space-based GW detectors. Additionally, we find that the strong backreaction due to particle production leads to multiple peaks in the energy spectrum of GWs.

Next-generation gravitational-wave instruments are expected to constrain the equation of state of dense nuclear matter by observing binaries involving neutron stars. We highlight a problematic systematic error in finite-temperature merger simulations, where shock heating associated with the neutron-star surface gives rise to elevated temperatures. We demonstrate the severe implications of this artificial heating by computing static and dynamical tidal parameters for neutron stars immersed in simulation temperature profiles. The induced systematic errors must be addressed if we want to build robust gravitational-wave signal models for neutron-star, or indeed neutron star-black hole, binaries.

It has been suggested that the Galactic Center gamma-ray excess (GCE) could be produced by a large number of centrally located millisecond pulsars. The fact that no such pulsar population has been detected implies that these sources must be very faint and very numerous. In this study, we use the contents of Fermi’s recently released Third Pulsar Catalog (3PC) to measure the luminosity function of the millisecond pulsars in the Milky Way’s disk. We find that this source population exhibits a luminosity function with a mean $\gamma$-ray luminosity of $⟨L_{\gamma }⟩\sim 6\times {10}^{32}\mathrm{erg}/\mathrm{s}$ (integrated above 0.1 GeV). If the GCE were generated by millisecond pulsars with the same luminosity function, we find that $\sim 20$ such sources from the inner Galaxy population should have already been detected by Fermi and included in the 3PC. Given the lack of such observed sources, we exclude the hypothesis that the GCE is generated by pulsars with the same luminosity function as those in the Galactic disk with a significance of $3.4\sigma$. We conclude that either less than 39% of the GCE is generated by pulsars, or that the millisecond pulsars in the inner Galaxy are at least 5 times less luminous on average than those found in the Galactic disk.

A large population of binary systems in the Universe emitting gravitational waves (GW) would produce a stochastic noise, known as the gravitational wave background (GWB). The properties of the GWB directly depend on the attributes of its constituents. If the binary systems are in eccentric orbits, it is well established that the GW power they radiate strongly depends on their instantaneous orbital phase. Consequently, their power spectrum varies over time, and the resulting GWB can appear nonstationary. In this work, we estimate the amplitude of time-dependent fluctuations in the GWB power spectrum as a function of the eccentricity of the binaries. Specifically, we focus on the GWB produced by a population of supermassive black hole binaries (SMBHB) that should be observable by pulsar timing arrays (PTA). We show that a large population of homogeneously distributed equal SMBHBs produces nonstationary features that are undetectable by current PTA datasets. However, using more realistic and astrophysically motivated populations of SMBHBs, we show that the nonstationarity might become very large and detectable, especially in the case of more massive and eccentric populations. In particular, when one binary is slightly brighter than the GWB, we demonstrate that time fluctuations can become significant. This is also true for individual binary systems with a low signal-to-noise ratio (SNR) relative to the GWB ($\mathrm{SNR}\approx 1$), which standard data analysis methods would struggle to detect. The detection of nonstationary features in the GWB could indicate the presence of some relatively bright GW sources in eccentric orbits, offering new insights into the origins of the signal. This will be particularly relevant for PTAs using observations from the next generation of radio telescopes, as they will offer high-precision measurements of GWB properties and increased sensitivity to time-dependent fluctuations.

Scalar field dark matter (SFDM) made of bosons has become a popular alternative to the cold dark matter (CDM) paradigm, especially for its potential to cure the so-called “small-scale problems” of CDM structure formation. Cosmological simulations have determined that SFDM halos exhibit a core-envelope structure, but they are computationally expensive. Halo cores have been found to be well approximated by “solitons,” i.e. equilibrium structures of the underlying equations of motion. The study of single soliton and multiple soliton merger dynamics constitutes a more feasible approach to investigate in detail the genuine quantum dynamics of SFDM and its interplay with self-gravity for a multitude of free boson parameters. In this paper, we present dedicated simulations of single solitons and binary soliton mergers, for models without and with a 2-boson, repulsive, weak to intermediate self-interaction (SI), as well as multiple soliton mergers without SI. We adapt the open-source code pyultralight to simulate solitons with SI and make our amended code available to the public. We derive numerical scaling relations between the central density and mass of solitons for several values of SI and find deviations from the monotonic relations known from fuzzy dark matter (no SI) or the strongly repulsive Thomas-Fermi regime. Solitons with SI exemplify larger cores and lower central densities, compared to solitons without SI. Using our simulations, we extract numerical density profiles for solitons and postmerger objects and fit them to analytical functions used in previous literature. For the cases considered, we find a mild preference for Gaussian cores for objects with SI, while the envelopes of postmergers can be fit to NFW profiles albeit with caution as we discuss. We find global, persistent oscillations for solitons as well as postmergers, confirming that self-gravitating SFDM has very long relaxation times, although objects with repulsive SI exhibit oscillations of comparatively smaller amplitude.