The sensitivity of wide parameter-space searches for continuous gravitational waves (CWs) is limited by their high computational cost. Deep learning is being studied as an alternative method to replace various aspects of a CW search. In previous work [Phys. Rev. D 108, 063021 (2023)], new design principles were presented for deep neural network (DNN) search of CWs and such DNNs were trained to perform a targeted search with matched-filtering sensitivity. In this paper, we adapt these design principles to build a DNN architecture for wide parameter-space searches in 10 days of data from two detectors (H1 and L1). We train a DNN for each of the benchmark cases: six all-sky searches and eight directed searches at different frequencies in the search band of $20–1000\mathrm{Hz}$. We compare our results to the DNN sensitivity achieved from Dreissigacker and Prix [Phys. Rev. D 102, 022005 (2020)] and find that our trained DNNs are more sensitive in all the cases. The absolute improvement in detection probability ranges from 6.5% at 20 Hz to 38% at 1000 Hz in the all-sky cases and from 1.5% at 20 Hz to 59.4% at 500 Hz in the directed cases. An all-sky DNN trained on the entire search band of 20–1000 Hz shows a high sensitivity at all frequencies, providing a proof of concept for training a single DNN to perform the entire search. We also study the generalization of the DNN performance to signals with different signal amplitude, frequency, and the dependence of the DNN sensitivity on sky position.

Central to black hole perturbation theory calculations is the Teukolsky equation that governs the propagation and the generation of radiation emitted by Kerr black holes. However, it is plagued by a long-ranged potential associated with the perturbation equation and hence a direct numerical integration of the equation is challenging. Sasaki and Nakamura devised a formulation that transforms the equation into a new equation that is free from the issue for the case of outgoing gravitational radiation. The formulation was later generalized by Hughes to work for any type of radiation. In this work, we revamp the generalized Sasaki-Nakamura (GSN) formalism and explicitly show the transformations that convert solutions between the Teukolsky and the GSN formalism for both in- and outgoing radiation of scalar, electromagnetic, and gravitational types. We derive all necessary ingredients for the GSN formalism to be used in numerical computations. In particular, we present a new numerical implementation of the formalism, GeneralizedSasakiNakamura.jl, that computes homogeneous solutions to both perturbation equations in the Teukolsky and the GSN formalism. The code works well at low frequencies and is even better at high frequencies by leveraging the fact that black holes are highly permeable to waves at high frequencies. This work lays the foundation for an efficient scheme to compute gravitational radiation from Kerr black holes and an alternative way to compute quasinormal modes of Kerr black holes.

We present BHPTNRSur2dq1e3, a reduced order surrogate model of gravitational waves emitted from binary black hole (BBH) systems in the comparable to large mass ratio regime with aligned spin (${\chi }_1$) on the heavier mass ($m_1$). We trained this model on waveform data generated from point particle black hole perturbation theory (ppBHPT) with mass ratios varying from $3\le q\le 1000$ and spins from $-0.8\le {\chi }_1\le 0.8$. The waveforms are 13,500 $m_1$ long and include all $\ell \le 4$ spin-weighted spherical harmonic modes except the (4,1) and $m=0$ modes. We find that, for binaries with ${\chi }_1\lesssim -0.5$, retrograde quasinormal modes are significantly excited, thereby complicating the modeling process. To overcome this issue, we introduce a domain decomposition approach to model the inspiral and merger-ringdown portion of the signal separately. The resulting model can faithfully reproduce ppBHPT waveforms with a median time-domain mismatch error of $8\times {10}^{-5}$. We then calibrate our model with numerical relativity (NR) data in the comparable mass regime ($3\le q\le 10$). By comparing with spin-aligned BBH NR simulations at $q=15$, we find that the dominant quadrupolar (subdominant) modes agree to better than $\approx {10}^{-3}$ ($\approx {10}^{-2}$) when using a time-domain mismatch error, where the largest source of calibration error comes from the transition-to-plunge and ringdown approximations of perturbation theory. Mismatch errors are below $\approx {10}^{-2}$ for systems with mass ratios between $6\le q\le 15$ and typically get smaller at larger mass ratio. Our two models—both the ppBHPT waveform model and the NR-calibrated ppBHPT model—will be publicly available through gwsurrogate and the black hole perturbation toolkit packages.

Draining vortices with a free surface are frequently employed as rotating black hole simulators, both in theory and experiments. However, most theoretical work is restricted to the idealized regime, where wave dispersion and dissipation are neglected. We investigate the role of these effects on the analog black hole bomb, an instability resulting from rotational superradiant amplification in confined systems. We reveal that the dispersion of deep water capillary-gravity waves significantly modifies the unstable mode eigenfrequencies, whereas viscosity only affects those with high frequencies. Furthermore, if the circulation is less than an order 1 multiple of the drain rate, superradiance does not occur and the vortex is stable. The instability is maximized in small systems with high flow velocities, provided there is sufficient space between the vortex and the outer boundary for the first excited state to lie inside the superradiant bandwidth. Implications for experiments on analog black holes and free surface vortices are discussed.

We present a novel semicoherent targeted search method for continuous gravitational waves (CWs) emitted by pulsars in binary systems. The method is based on a custom optimization of the coherence time, which is tailored according to the orbital parameters and their uncertainties, as provided by electromagnetic observations. While rotating pulsars are expected to produce quasimonochromatic CWs in their reference frame, their orbital motion introduces additional modulation in the observer’s frame, alongside the modulation caused by the Earth’s motion. As a result, the received signal is spread across a frequency range, and demodulation techniques must be used to improve sensitivity. However, Doppler corrections can, in some cases, vary significantly within the uncertainties of the orbital parameters, potentially lowering the detection chances of single-template, fully coherent searches. To exploit the constraints derived from electromagnetic observations, we implement a semicoherent search that is more robust than other methods. In this approach, the coherence time is evaluated for each source, taking into account the uncertainties in its orbital parameters. This method was tested and applied to a set of thirteen targets from the ATNF catalog. The search identified one outlier, whose astrophysical origin has been confidently excluded. For the first time to our knowledge, we then set upper limits on the signal strain from these 12 pulsars, with the lowest limit being $h_{UL}\sim 9.01\times {10}^{-26}$ for PSR J1326-4728B.

Transiently accreting low mass x-ray binaries have the potential to probe the core composition of their neutron stars via deep crustal heating caused by nuclear reactions. We statistically assess this deep crustal heating scenario, taking into account the various microphysical and astrophysical uncertainties. We find that despite the sizable uncertainties there is the chance to discriminate different compositional scenarios. Several observed sources statistically challenge a minimal hadronic matter composition, where cooling proceeds exclusively via slow modified Urca reactions. Considering here two exemplary extended uniform compositions, namely ultradense hadronic matter with direct Urca emission and ungapped quark matter, we find that they are even within uncertainties distinguishable. We show that although exotic forms of matter are generally only expected in an inner core, which could in principle have any size, sufficiently large astrophysical datasets nonetheless have the potential to statistically discriminate compositional scenarios, in particular when further mass measurements become available.

In this study, we analyze the transport properties of the quark-gluon plasma (QGP), focusing on bulk ($\zeta$) and shear ($\eta$) viscosities at vanishing chemical potential. To describe the QGP, we employ a quasiparticle model for quarks along with Gribov’s prescription for gluons, which effectively captures nonperturbative dynamics. The Gribov parameter ${\gamma }_G$ and the dynamical mass $m_g$ are obtained by solving the one-loop gap equation in the $\overline{\mathrm{MS}}$ renormalization scheme and further using lattice QCD data for the equation of state (EOS) of pure gluonic matter. The interaction between quarks and gluons is reflected in the quark quasimass $m_q$, again obtained using lattice EOS data for ($2+1$)-flavor QCD. Our primary goal is to investigate the influence of quasiquarks on the transport coefficients of QGP. Interestingly, we find a substantial decrease in the scaled transport coefficients with rising temperatures within the range ($1\le T/T_c\le 3.5$).

We describe an algorithm to organize Feynman integrals in terms of their infrared properties. Our approach builds upon the theory of Landau singularities, which we use to classify all configurations of loop momenta that can give rise to infrared divergences. We then construct bases of numerators for arbitrary Feynman integrals, which cancel all singularities and render the integrals finite. Through the same analysis, one can also classify so-called evanescent and evanescently finite Feynman integrals. These are integrals whose vanishing or finiteness relies on properties of dimensional regularization. To illustrate the use of these integrals, we display how to obtain a simpler form for the leading-color two-loop four-gluon scattering amplitude through the choice of a suitable basis of finite integrals. In particular, when all gluon helicities are equal, we show that with our basis the most complicated double-box integrals do not contribute to the finite remainder of the scattering amplitude.

The $U(1{)}_{L_{\mu }-L_{\tau }}$ $Z^{\prime }$ model has emerged as a promising candidate to address the longstanding muon $(g-2{)}_{\mu }$ anomaly. Flavor-conserving $Z^{\prime }$ interactions are subject to stringent constraints from the neutrino trident process and $\mathrm{NA}64\mu$ experiments, which limit the $Z^{\prime }$ mass to $m_{Z^{\prime }}<40\mathrm{MeV}$. To circumvent these constraints, flavor-conserving $Z^{\prime }$ interactions can be converted into maximal flavor-violating interactions through a discrete exchange symmetry. Maximal flavor-violating $Z^{\prime }$ interactions contribute to $\tau \to \mu \nu \overline{\nu }$ via the neutral current, yet the parameter space for this process conflicts with the $(g-2{)}_{\mu }$ allowed regions. To resolve this conflict, we propose introducing a singly charged scalar that mediates via charged current interactions. This scalar is anticipated to produce a negative contribution to the lepton $(g-2{)}_l$ while concurrently inducing the tau decay $\tau \to \mu \nu \overline{\nu }$. Three distinct scenarios arise from the introduction of singly charged scalars: the ${\mathcal{O}}_{LL}$ operator, driven by weak singlet and triplet, and the ${\mathcal{O}}_{LR}$ operator, driven by weak doublet. Our analysis of the phenomenology in these three cases reveals that the tension between the muon $(g-2{)}_{\mu }$ anomaly and $\tau \to \mu \nu \overline{\nu }$ for large $Z^{\prime }$ masses can be effectively alleviated only by the singly charged scalars from the weak triplet, whereas the singlet and doublet scenarios fall short. Furthermore, the singly charged scalars from the weak triplet offer an additional explanation for the electron $(g-2{)}_e$ anomaly. Our findings indicate that weak triplets could play a crucial role in $Z^{\prime }$ models, potentially providing valuable insights for future research into $U(1)$ frameworks.

We study the upper limit on dark matter mass in the context of the inert doublet model. We derive an analytic expression for the upper bound as a function of the mass squared differences between dark matter and other new particles. We find that the upper limit varies between 20 and 80 TeV depending on the mass squared splitting.

The ATLAS and CMS collaborations reported a diphoton excess in the invariant mass distribution around the 95.4 GeV with a local significance of $3.1\sigma$. Moreover, there is another $2.3\sigma$ local excess in the $b\overline{b}$ final state at large electron-positron collider in the same mass region. A plausible solution is that the Higgs sector is extended to include an additional Higgs boson with a mass of 95.4 GeV. We study a complex singlet scalar extension of the two-Higgs-doublet model in which the 95.4 GeV Higgs is from the mixing of three $CP$-even Higgs fields. In addition, the extended Higgs potential can achieve spontaneous $CP$-violation at the finite temperature and restore $CP$ symmetry at the present temperature of the Universe. We find that the model can simultaneously explain the baryon asymmetry of the Universe, the diphoton and $b\overline{b}$ excesses around the 95.4 GeV while satisfying various relevant constraints including the experiments of collider and electric dipole moment.

The dark matter conundrum stands out as one of the central challenges to understand in both particle physics and cosmology. The ultralight axionlike particle (UALP) is an appealing dark matter candidate that can be searched for in neutrino oscillation experiments. In this work, we examine the interaction among neutrinos and a UALP—such interaction might induce violations of the Lorentz and $CPT$ symmetries. We assess the sensitivity to both the isotropic $CPT$-odd standard model extension coefficients $(a_L{)}^T$ and effective neutrino-UALP couplings $\tilde{g}$ at the next-to-next-generation neutrino oscillation experiment at the European Spallation Source.

We perform a systematical investigation of the singly charmed dibaryon system with strangeness numbers $S=-1$, $-3$, and $-5$ in the framework of the chiral quark model. Two resonance states with strangeness numbers $S=-1$ are obtained in the baryon-baryon scattering process. In the $\mathrm{\Lambda }{\mathrm{\Lambda }}_c$ and $N{\mathrm{\Xi }}_c^{*}$ scattering phase shifts, the $\mathrm{\Sigma }{\mathrm{\Sigma }}_c$ appears as a resonance state with the mass and width 3591–3614 MeV and 11.75 MeV, respectively. In the $N{\mathrm{\Xi }}_c$ and $N{\mathrm{\Xi }}_c^{\prime }$ scattering phase shifts, the $\mathrm{\Sigma }{\mathrm{\Sigma }}_c^{*}$ exhibits as a resonance state with the mass and width 3621–3624 MeV and 14.9 MeV, respectively. All these heavy-flavor dibaryons are worth searching for in experiments. Besides, we would like to emphasize that the coupling calculation between the bound channels and open channels is indispensable. The study of the scattering process maybe an effective way to look for the genuine resonances.

We study electron-positron pair production within two counterpropagating, circularly polarized electromagnetic fields through the Wigner formalism. We numerically generate high-resolution momentum maps to perform a detailed spectroscopic analysis. We identify signatures of polarization and kinematics of the incident fields in the final positron distribution and, on this basis, provide an intuitive picture of helicity transfer in multiphoton pair production.

We derive the finite-temperature quantum-tunneling rate from first principles. The tunneling rate depends on both temperature and time. We demonstrate that the relevant instantons should, therefore, be defined on a Keldysh-Schwinger contour, and we discuss how the familiar Euclidean time result arises from the limit of large physical times. We identify distinct behavior in the high- and low-temperature limits, incorporating effects from background fields. We construct a consistent perturbative scheme that incorporates large finite-temperature effects.

In the Standard Model, some combination of the baryon $\mathbf{B}$ and lepton $\mathbf{L}$ number symmetry is free of mixed anomalies with strong and electroweak $su(3)\times su(2)\times u(1{)}_{\tilde{Y}}$ gauge forces. However, it can still suffer from a mixed gravitational anomaly, hypothetically pertinent to leptogenesis in the very early Universe. This happens when the total “sterile right-handed” neutrino number $n_{{\nu }_R}$ is not equal to the family number $N_f$. Thus, the invertible $\mathbf{B}-\mathbf{L}$ symmetry current conservation can be violated quantum mechanically by gravitational backgrounds such as gravitational instantons. Specifically, we show that a noninvertible categorical $\mathbf{B}-\mathbf{L}$ generalized symmetry still survives in gravitational backgrounds. In general, we propose a construction of noninvertible symmetry charge operators as topological defects derived from invertible anomalous symmetries that suffer from mixed gravitational anomalies. Examples include the perturbative local and nonperturbative global anomalies classified by $\mathbb{Z}$ and ${\mathbb{Z}}_{16}$, respectively. For this construction, we utilize the anomaly inflow bulk-boundary correspondence, the 4D Pontryagin class and the gravitational Chern-Simons 3-form, the 3D Witten-Reshetikhin-Turaev-type topological quantum field theory with a framing anomaly corresponding to a 2D rational conformal field theory with an appropriate rational chiral central charge, and the 4D ${\mathbb{Z}}_4^{\mathrm{TF}}$-time-reversal symmetric topological superconductor with 3D boundary topological order.

We study quasinormal modes of massive scalar perturbations in Kerr black holes using the isomonodromic method. For arbitrary scalar masses $M\mu$ and black hole spins $a/M$, we numerically determine the quasinormal frequencies for various orbital $\ell$, azimuthal $m$, and overtone $n$ numbers. In particular, we derive an analytic expression for frequencies of the zero-damping modes near the extremal limit $a/M\to 1$. For $\ell =m=1$, we reveal that the fundamental mode becomes a damped mode (rather than a zero-damping mode) if the scalar field is sufficiently heavy. By exploring the parameter space, we find numerical evidence for level crossing between the longest-living mode and the first overtone at an exceptional point $(M\mu {)}_c\simeq 0.3704981$ and $(a/M{)}_c\simeq 0.9994660$.

In this work, we systematically study both the mass spectra and strong decays of the nucleon and $\mathrm{\Delta }$ resonances up to the $N=2$ shell within a unified quark model framework with chiral dynamics. In this framework we achieve a good description of the strong decay properties of the well-established nucleon and $\mathrm{\Delta }$ resonances. Meanwhile, the mass reversal between $N(1440)1/2^{+}$ as the first radial excitation state and the $1P$-wave nucleon resonances can be explained. We show that the three-body spin-orbit potential arising from the one-gluon exchange can cause a large configuration mixing between $N(1520)3/2^{-}$ and $N(1700)3/2^{-}$ and is also responsible for the large splitting between $\mathrm{\Delta }(1600)1/2^{-}$ and $\mathrm{\Delta }(1700)3/2^{-}$. Some of these baryon resonances tend to weakly couple to the $N\pi$, $N\eta$, $K\mathrm{\Lambda }$, and $K\mathrm{\Sigma }$ channels, which may answer the question of why they have not been established in these channels via the $\pi N$ and $\gamma N$ scatterings. It shows that these “missing resonances” may have large potentials to be established in the $N\pi \pi$ final state due to their large decay rates into either the $\mathrm{\Delta }(1232)$ or $1P$-wave nucleon resonances via the pionic decays. Further experimental search for their signals in charmonium decays at BESIII is thus strongly recommended.

Previous investigations on the renormalizability properties of Lorentz-violating Yang-Mills (LVYM) theories in the Landau gauge have pointed out the necessity of the inclusion of a masslike term for the gauge fields. If one aims at generalizing the theory to a more complicated gauge, such a masslike term can bring severe issues regarding gauge dependence of correlation functions of observables. We propose a Lorentz-violating Yang-Mills theory supplemented by a gauge-invariant mass term which generalizes the model in the Landau gauge. We discuss the foundational aspects of the model and highlight how it simplifies in the Landau gauge. Following the recent literature in pure Yang-Mills theories, we remark how the proposed massive extension of LVYM theories can be used as an effective model to access infrared properties within perturbation theory. Finally, we present a Becchi-Rouet-Stora-Tyutin-invariant formulation of the so-called refined Gribov-Zwanziger action in the presence of Lorentz-violating terms in linear covariant gauges and the underlying tree-level gauge-field propagator which is enriched by the nonperturbative information carried by the elimination of Gribov copies.

We present a hydrodynamic framework derived from the action of a perfect fluid, modified by the hydrodynamic analog of Novikov’s multivalued functional. This modification introduces spin degrees of freedom into the fluid. The structure closely resembles the Abelian version of the Wess-Zumino functional, commonly applied in field theories with chiral anomalies. The deformation incorporates transport properties of Weyl fermions and, in the case of a charged fluid, exhibits the chiral anomaly. It is also consistent with Onsager’s semiclassical quantization of circulation. Additionally, we discuss the hydrodynamic analog of instantons and related topological invariants.