It is natural to wonder whether there may be observational relics of new fundamental fields, beyond the inflaton, in large scale structure. Here we discuss the phenomenology of a model in which compensated isocurvature perturbations (CIPs) arise through the action of a primordial vector field that displaces dark matter relative to baryons. The model can be tested best by kinematic-Sunyaev-Zeldovich tomography, which involves the cross-correlation of cosmic microwave background and galaxy surveys, with next-generation observatories. There are also signatures of the vectorial nature of the new field that may be detectable in forthcoming galaxy surveys, but the galaxy survey cannot alone indicate the presence of a CIP. Models that induce a parity breaking four-point correlation in the galaxy distribution are also possible.

In this study, we conduct a detailed analysis of the dissipation coefficient ($Q$) of warm Higgs inflation (WHI), which exerts important influences on the entire warm inflation process. By deriving the relationships between various quantities and $Q$, one can avoid a priori assumptions, i.e., strong dissipation ($Q\gg 1$) or weak dissipation ($Q\ll 1$). Taking into account the constraints imposed by the cosmic microwave background, the dissipation the coefficient $Q$ remains at extremely low levels throughout the entire warm inflation process, i.e., $Q\ll 1$. This observation indicates that WHI falls under the category of weak dissipation warm inflation. Despite being weak dissipation, $Q$ still plays a non-negligible role in the evolution of temperature, energy, and other quantities. We delve into the impact of the primordial power spectrum on the dissipation coefficient $Q$ during the warm inflation process, discovering that the dependency is not significant. Consequently, this results in a weak sensitivity of the gravitational wave spectrum (${\mathrm{\Omega }}_{\mathrm{GW},0}{h}^2$) to changes in $Q$. In addition, the variation of tensor-to-scalar ratio $r$ has a significant effect on the ${\mathrm{\Omega }}_{\mathrm{GW},0}{h}^2$ of cold inflation and a small effect on WHI. Finally, gravitational waves generated by WHI hold the potential for verification in future observational experiments, especially through the SKA100 experiment.

Many theories of physics beyond the Standard Model predict the existence of large or infinite towers of decaying states. In a previous paper [K. R. Dienes et al., Phys. Rev. D 105, 023530 (2022)], we pointed out that this can give rise to a surprising cosmological phenomenon that we dubbed “stasis” during which the relative abundances of matter and radiation remain constant across extended cosmological eras even though the universe is expanding. Indeed, such stasis epochs are universal attractors, with the universe necessarily entering (and later exiting) such epochs for a wide variety of initial conditions. Matter/radiation stasis is therefore an important and potentially unavoidable feature of many BSM cosmologies. In this paper we extend our arguments to universes containing significant amounts of vacuum energy, and demonstrate that such universes also give rise to various forms of stasis between vacuum energy and either matter or radiation. We also demonstrate the existence of several forms of “triple stasis” during which the abundances of matter, radiation, and vacuum energy all simultaneously remain fixed despite cosmological expansion. We further describe several close variants of stasis which we call “quasi-stasis” and “oscillatory stasis,” and discuss the circumstances under which each of these can arise. Finally, we develop a general formalism for understanding the emergence of stasis within BSM cosmologies irrespective of the number or type of different energy components involved. Taken together, these results greatly expand the range of theoretical and phenomenological possibilities for the physics of the early universe, introducing new types of cosmological eras which may play an intrinsic and potentially inevitable role within numerous BSM cosmologies.

The existence of large-scale anisotropy cannot be ruled out by the cosmic microwave background (CMB) radiation. Over the years, several models have been proposed in the context of anisotropic inflation to account for the CMB’s cold spot and hemispheric asymmetry. However, any small-scale anisotropy, if it exists during inflation, is not constrained, due to its nonlinear evolution in the subsequent phase. This small-scale anisotropy during inflation can play a nontrivial role in giving rise to the cosmic magnetic field, which is the subject of our present study. Assuming a particular phenomenological form of an anisotropic inflationary universe, we have shown that it can generate a large-scale magnetic field at the 1 Mpc scale with a magnitude $\sim 4\times {10}^{-20}\mathrm{G}$, within the observed bound. Because of the anisotropy, the conformal flatness property is lost, and the Maxwell field is generated even without explicit coupling. This immediately resolves the strong coupling problem in the standard magnetogenesis scenario. In addition, assuming very low conductivity during the reheating era, we can further observe the evolution of the electromagnetic field with the equation of state ${\omega }_{\mathrm{eff}}$ and its effects on the present-day magnetic field.

Primordial black hole (PBH) formation during cosmic phase transitions and annihilation periods, such as the QCD transition or the $e^{+}{e}^{-}$ annihilation, is thought to be particularly efficient due to a softening of the equation of state. We present a detailed numerical study of PBH formation during the QCD epoch in order to derive an accurate PBH mass function. We also briefly consider PBH formation during the $e^{+}{e}^{-}$-annihilation epoch. Our investigation confirms that, for nearly scale-invariant spectra, PBH abundances on the QCD scale are enhanced by a factor $\sim {10}^3$ compared to a purely radiation dominated Universe. For a power spectrum producing an (almost) scale-invariant PBH mass function outside of the transition, we find a peak mass of $M_{\mathrm{pbh}}\approx 1.9M_{\odot }$ with a fraction $f\approx 1.5\times {10}^{-2}$ of the PBHs having a mass of $M_{\mathrm{pbh}}>10M_{\odot }$, possibly contributing to the LIGO-Virgo black hole merger detections. We point out that the physics of PBH formation during the $e^{+}{e}^{-}$-annihilation epoch is more complex as it is very close to the epoch of neutrino decoupling. We argue that neutrinos free-streaming out of overdense regions may actually hinder PBH formation.

Gravitational waves (GWs) from compact binary coalescences can constrain the cosmic expansion of the Universe. In the absence of an associated electromagnetic counterpart, the spectral siren method exploits the relation between the detector frame and the source frame masses to jointly infer the parameters of the mass distribution of black holes (BHs) and the cosmic expansion parameter $H_0$. This technique relies on the choice of the parametrization for the source mass population of BHs observed in binary black hole mergers (BBHs). Using astrophysically motivated BBH populations, we study the possible systematic effects affecting the inferred value for $H_0$ when using heuristic mass models like broken power law, power law plus peak, and multipeak distributions. We find that, with 2000 detected GW mergers, the resulting $H_0$ obtained with a spectral siren analysis can be biased up to $3\sigma$. The main sources of this bias come from the failure of the heuristic mass models used so far to account for a possible redshift evolution of the mass distribution and from their inability to model unexpected mass features. We conclude that future dark siren GW cosmology analyses should make use of source mass models able to account for redshift evolution and capable to adjust to unforeseen mass features.

We present a new subgrid model for neutrino quantum kinetics, which is primarily designed to incorporate effects of collective neutrino oscillations into neutrino-radiation-hydrodynamic simulations for core-collapse supernovae and mergers of compact objects. We approximate the neutrino oscillation term in a quantum kinetic equation using the Bhatnagar-Gross-Krook (BGK) relaxation-time prescription, and the transport equation is directly applicable for classical neutrino transport schemes. The BGK model is motivated by recent theoretical indications that nonlinear phases of collective neutrino oscillations settle into quasisteady structures. We explicitly provide basic equations of the BGK subgrid model for both multiangle and moment-based neutrino transport to facilitate the implementation of the subgrid model in the existing neutrino transport schemes. We also show the capability of our BGK subgrid model by comparing it to fully quantum kinetic simulations for fast neutrino-flavor conversion. We find that the overall properties can be well reproduced in the subgrid model; the error of angular-averaged survival probability of neutrinos is within $\sim 20\%$. By identifying the source of error, we also discuss perspectives to improve the accuracy of the subgrid model.

We investigate mass ejection from accretion disks formed during the collapse of rapidly rotating Wolf-Rayet stars. The neutrino-cooled, black hole (BH) accretion disk system that forms at the center of the star—and the ensuing outflows—provides the conditions for these systems to be candidate $r$-process element production sites and potential progenitors of broad-line type Ic (Ic-BL) supernovae. We present global, long-term axisymmetric hydrodynamic simulations of collapsar disks that include angular momentum transport through shear viscosity, neutrino emission and absorption, a 19-isotope nuclear reaction network and nuclear statistical equilibrium solver, a pseudo-Newtonian BH with mass and spin modified by accreted matter, and self-gravity. Starting with a stellar profile collapsed in spherical symmetry, our models capture disk formation self-consistently and are evolved until after the shock wave—driven by disk winds—reaches the surface of the star. None of our models achieve sufficient neutronization to eject significant amounts of $r$-process elements (detailed nucleosynthesis calculations will follow in a companion paper). Sufficient ${}^{56}\mathrm{Ni}$ is produced to power a typical type Ic-BL supernova light curve, but the average asymptotic velocity is a factor $\sim 2$ to 3 times too slow to account for the typical linewidths in type Ic-BL supernova spectra. The gap in neutrino emission between BH formation and shocked disk formation and the magnitude of the subsequent peak in emission would be observable diagnostics of the internal conditions of the progenitor in a galactic collapsar. Periodic oscillations of the shocked disk prior to its expansion are also a potential observable through their impact on the neutrino and gravitational wave signals.

We study zero temperature equations of state (EOS) in isospin QCD within a quark-meson model which is renormalizable and hence eliminates high density artifacts in models with the ultraviolet cutoff (e.g., Nambu-Jona-Lasinio type models models). The model exhibits a crossover transition of pion condensations from the Bose-Einstein-Condensation regime at low density to the Bardeen-Cooper-Schrieffer regime at high density. The EOS stiffens quickly and approaches the quark matter regime at density significantly less than the density for pions to spatially overlap. The squared sound velocity $c_s^2$ develops a peak in the crossover region, and then gradually relaxes to the conformal value $1/3$ from above, in contrast to the perturbative QCD results which predicts the approach from below. In the context of QCD computations, this opposite trend is in part due to the lack of gluon exchanges in our model, and also due to the nonperturbative power corrections arising from the condensates. We argue that with large power corrections the trace anomaly can be negative. Our EOS reproduces the qualitative trend of the lattice results from the BEC to the BCS regime, implying that the quark-meson model captures relevant effective degrees of freedom. The BCS gap in our model is $\mathrm{\Delta }\simeq 300\mathrm{MeV}$ in the quark matter domain, and naive application of the BCS relation for the critical temperature $T_c\simeq 0.57\mathrm{\Delta }$ yields the estimate $T_c\simeq 170\mathrm{MeV}$, in good agreement with the lattice data.

In this work we investigate the relation between higher-dimensional gauge theories and stochastic gravitational wave (GW) spectrums caused by their potential. It is known that the higher-dimensional gauge theories can induce the spontaneous symmetry breaking of the gauge symmetry. If the spontaneous symmetry breaking induces the first-order phase transition, the stochastic GW can be observed in future interferometers. Through our numerical calculations, we reveal that distinctive parameters in the theories, like the compact scale, can change the GW spectrums dynamically. We also discuss the verifiability of the theories through the GW observations.

Dark matter particles could be superheavy, provided their lifetime is much longer than the age of the Universe. Using the sensitivity of the Pierre Auger Observatory to ultrahigh energy neutrinos and photons, we constrain a specific extension of the Standard Model of particle physics that meets the lifetime requirement for a superheavy particle by coupling it to a sector of ultralight sterile neutrinos. Our results show that, for a typical dark coupling constant of 0.1, the mixing angle ${\theta }_m$ between active and sterile neutrinos must satisfy, roughly, ${\theta }_m\lesssim 1.5\times {10}^{-6}(M_X/{10}^9\mathrm{GeV}{)}^{-2}$ for a mass $M_X$ of the dark-matter particle between ${10}^8\mathrm{GeV}$ and ${10}^{11}\mathrm{GeV}$.

Topologically nontrivial fluctuations control the anomalous interactions for the $\eta$ and ${\eta }^{\prime }$ pseudoscalar mesons. We consider the anomalous interactions for mesons with higher spin, the heterochiral nonets with $J^{PC}=1^{+-}$ and $2^{-+}$. Under the approximation of a dilute gas of instantons, the mixing angle between nonstrange and strange mesons decreases strongly as $J$ increases, and oscillates in sign. Anomalous interactions also open up new, rare decay channels. For glueballs, anomalous interactions indicate that the $X(2600)$ state is primarily gluonic.

We consider the fermionic (logarithmic) negativity between two fermionic modes in the Schwinger model. Recent results pointed out that fermionic systems can exhibit stronger entanglement than bosonic systems, exhibiting a negativity that decays only algebraically. The Schwinger model is described by fermionic excitations at short distances, while its asymptotic spectrum is the one of a bosonic theory. We show that the two-mode negativity detects this confining, fermion-to-boson transition, shifting from an algebraic decay to an exponential decay at distances of the order of the de Broglie wavelength of the first excited state. We derive analytical expressions in the massless Schwinger model and confront them with tensor network simulations. We also perform tensor network simulations in the massive model, which is not solvable analytically, and close to the Ising quantum critical point of the Schwinger model, where we show that the negativity behaves as its bosonic counterpart.

Using a data sample corresponding to an integrated luminosity of $10.9{\mathrm{fb}}^{-1}$ collected at center-of-mass energies from 4.16 to 4.34 GeV with the BESIII detector, we search for the decay ${\chi }_{c1}(3872)\to {\pi }^{+}{\pi }^{-}{\chi }_{c1}$ in the radiative production $e^{+}{e}^{-}\to \gamma {\chi }_{c1}(3872)$. No significant signal is observed, and the ratio for the branching fraction of ${\chi }_{c1}(3872)\to {\pi }^{+}{\pi }^{-}{\chi }_{c1}$ to ${\chi }_{c1}(3872)\to {\pi }^{+}{\pi }^{-}J/\psi$ is measured as $\mathcal{R}\equiv \frac{\mathcal{B}[{\chi }_{c1}(3872)\to {\pi }^{+}{\pi }^{-}{\chi }_{c1}]}{\mathcal{B}[{\chi }_{c1}(3872)\to {\pi }^{+}{\pi }^{-}J/\psi ]}<0.18$ at 90% confidence level. An upper limit on the product of the cross section $\sigma [e^{+}{e}^{-}\to \gamma {\chi }_{c1}(3872)]$ and the branching fraction $\mathcal{B}[{\chi }_{c1}(3872)\to {\pi }^{+}{\pi }^{-}{\chi }_{c1}]$ at each center-of-mass energy is also given. These measurements favor the nonconventional charmonium nature of the ${\chi }_{c1}(3872)$ state.

The interior of a pure-state black hole is known to be reconstructed from the Petz map by collecting a sufficiently large amount of the emitted Hawking radiation. This was established based on the Euclidean replica wormhole, which comes from an ensemble averaging over gravitational theories. On the other hand, this means that the Page curve and the interior reconstruction are both ensemble averages; thus, there is a possibility of large errors. In the previous study [R. Bousso and M. Miyaji, Fluctuations in the entropy of Hawking radiation], it was shown that the entropy of the Hawking radiation has fluctuation of order $e^{-S_{\mathbf{BH}}}$, thus is typical in the ensemble. In the present article, we show that the fluctuations in the information recovery are similarly suppressed by the factor $e^{-S_{\mathbf{BH}}}$ by studying the fluctuations of the relative entropy difference in the encoding map and the entanglement fidelity of the Petz map. This result establishes the typicality of the information recovery in the ensemble. In addition, we also compute the entanglement loss of the encoding map.

In this paper, we use a five-dimensional Einstein-dilaton-two-Maxwell holographic QCD model to investigate the dissociation effects of $J/\mathrm{\Psi }$ and $\mathrm{\Upsilon }(1S)$ states in an anisotropic medium by calculating their spectral functions. First, we present the holographic quarkonium masses at zero temperature via physics-informed neural networks. Then, at a finite temperature, we derive the spectral functions, representing heavy vector mesons as peaks, and observe that with increasing anisotropy, temperature, chemical potential, and warp factor, the peak height diminishes while its width expands, indicating an accelerated dissociation process. Additionally, the results indicate the anisotropy induces a stronger dissociation effect in the direction parallel to the polarization compared to the perpendicular, revealing the anisotropy’s directional influence.

We examine the gravitational lensing phenomenon caused by photon spheres in the Born-Infeld naked singularity spacetime, where gravity is coupled with Born-Infeld electrodynamics. Specifically, our focus lies on relativistic images originating from a pointlike light source generated by strong gravitational lensing near photon spheres, as well as images of a luminous celestial sphere. It shows that Born-Infeld naked singularities consistently exhibit one or two photon spheres, which project onto one or two critical curves on the image plane. Our analysis reveals that when appropriately regularized, the singularity allows photons entering the photon sphere(s) to traverse it. This, in turn, leads to the emergence of new relativistic images within the innermost critical curve. Furthermore, the presence of two photon spheres doubles the number of relativistic images compared to the scenario with only a single photon sphere. Additionally, the transparency inherent to Born-Infeld naked singularities results in the absence of a central shadow in the images of celestial spheres.

We present for the first time a study of the quasinormal modes of rapidly rotating Ellis-Bronnikov wormholes in general relativity. We compute the spectrum of the wormholes using a spectral decomposition of the metric perturbations on a numerical background. We focus on the $M_z=2$, 3 sector of the perturbations, and show that the triple isospectrality of the symmetric and static Ellis-Bronnikov wormhole is broken due to rotation, giving rise to a much richer spectrum than the spectrum of Kerr black holes. We do not find any instabilities for $M_z=2$, 3 perturbations.

We consider a Dirac-Proca star (DPS) model that consists of the Einstein gravity in four-dimensional spacetime, a Proca field, and two Dirac fields through minimal coupling. By numerically solving this model, we obtain two types of solutions: synchronized frequency solutions and nonsynchronized frequency solutions. We find that in the case of two kinds of matter fields, different families of solutions can be obtained in both synchronized and nonsynchronized frequency cases, and the two families can shift to each other when certain parameters are changed. Moreover, we calculate the binding energy of multifield solutions and give the relationship between binding energy $E$ and synchronized frequency $\tilde{\omega }$ (nonsynchronized frequency ${\tilde{\omega }}_P$).