We present two kinds of resonance soliton solutions on the ultrahyperbolic space $\mathbb{U}$ for the $G=U(2)$ Yang equation, which is equivalent to the anti-self-dual Yang-Mills (ASDYM) equation. We reveal and illustrate the solitonic behaviors in the four-dimensional Wess-Zumino-Witten (${\mathrm{WZW}}_4$) model through the sigma model action densities. The Yang equation is the equation of motion of the ${\mathrm{WZW}}_4$ model. In the case of $\mathbb{U}$, the ${\mathrm{WZW}}_4$ model describes a string field theory action of open $N=2$ string theories. Hence, our solutions on $\mathbb{U}$ suggest the existence of the corresponding classical objects in the $N=2$ string theories. Our solutions include multiple-pole solutions and V-shape soliton solutions. The V-shape solitons suggest annihilation and creation processes of two solitons and would be building blocks to classify the ASDYM solitons, like the role of Y-shape solitons in classification of the Kadomtsev-Petviashvili (line) solitons. We also clarify the relationship between the Cauchy matrix approach and the binary Darboux transformation in terms of quasideterminants. Our formalism can start with a simpler input data for the soliton solutions and hence might give a suitable framework for the classification of the ASDYM solitons.

We consider a generalization of the double Liouville theory, which can be thought of as a two-parameter family of deformations of the so-called Virasoro minimal string (VMS). The latter consists of a timelike ($c_{-}<1$) and a spacelike ($c_{+}>25$) Liouville field theory formulated on a fluctuating Riemann surface. For the deformed theory, we compute the sphere partition function exactly in $1/c_{\pm }$ and at third order in the coupling constant ($\lambda$) that controls the deformation. We also discuss the analogous computation in the case of the complex Liouville string (CLS) theory, which is defined as two spacelike Liouville theories with complex central charges $c_{\pm }=13\pm i{\mathbb{R}}_{>0}$. We show that the partition functions of VMS and CLS differ at leading order in $\lambda$ due to the presence of elliptic functions in the observables of the latter. Both VMS and CLS theories have recently been studied in relation to many interesting models, including the double-scaled Sachdev-Ye-Kitaev model, matrix models, and de Sitter gravity in two and three dimensions. We comment on the interpretation of the marginal deformation in some of these contexts.

Based on the renormalization group (RG) flow of worldsheet bosonic string theory, we construct an effective holographic dual description of the target space theory identifying the RG scale with the emergent extra dimension. This results in an effective dilaton-gravity-gauge theory, analogous to the low-energy description of bosonic M theory. We argue that this holographic dual effective field theory is nonperturbative in the ${\alpha }^{\prime }$ expansion, where a class of string quantum fluctuations are resummed to all orders. To investigate the monotonicity of the RG flow of the target space metric in the emergent spacetime, we consider entropy production along the RG flow. We construct a microscopic entropy functional based on the probability distribution function of the holographic dual effective field theory, regarded as Gibbs- or Shannon-type entropy. Given that the Ricci flow represents the 1-loop RG flow equation of the target space metric for the 2D nonlinear sigma model, and motivated by Perelman’s proof of the monotonicity of Ricci flow, we propose a Perelman’s entropy functional for the holographic dual effective field theory. This entropy functional is also nonperturbative in the ${\alpha }^{\prime }$ expansion, and thus, generalizes the 1-loop result to the all-loop order. Furthermore, utilizing the equivalence between the Hamilton-Jacobi equation and the local RG equation, we suggest that the RG flow of holographic Perelman’s entropy functional is the Weyl anomaly. This eventually reaffirms the monotonicity of RG flow for the emergent target spacetime but in a nonperturbative way. Interestingly, we find that the microscopic entropy production rate can be determined by integrating the rate of change of the holographic Perelman’s entropy functional over all possible metric configurations along the flow.

We examine the vacuum state and its corresponding renormalized stress-energy tensor (RSET) in static horizonless regular spacetime in both two and four dimensions. Using the local field formulation of the anomaly-induced effective action, we show that the regularities of the spacetime and the RSET dictate the appropriate vacuum state. Furthermore, through a case study under the horizonless Bardeen-type spacetime, we demonstrate that the preferred vacuum state is not the Boulware vacuum, but a nontrivial one with a different RSET profile.

Four-dimensional asymptotically flat spacetimes have been central to recent developments in infrared physics. Gravitational waves reaching the asymptotic boundary reveal an infinite-dimensional symmetry group known as the Bondi-Metzner-Sachs group. The vacuum structure breaks this symmetry, giving rise to Goldstone modes that play a pivotal role in the analysis of scattering amplitudes. However, these modes must be added to the phase space of the metric formulation. In this work, we explore an alternative formulation of general relativity, teleparallel gravity, which is dynamically equivalent to the standard metric description in the bulk. This framework relies on a tetrad field to encode the gravitational degrees of freedom and a flat connection to represent inertial effects. Leveraging this decomposition, we propose a novel encoding of the Goldstone modes within the flat connection. We examine the implications of this approach in the covariant phase space framework, focusing on the symplectic potential and its connection to the Wald-Zoupas prescription.

In space-based gravitational wave observatories such as Taiji, LISA, and TianQin, data gaps are inevitable due to mission design, implementation, and the long duration of observations. These data gaps degrade data quality and cause spectral leakage during Fourier transformations. Since ringdown signals are a key scientific objective for these observatories, it is crucial to assess the impact of data gaps on ringdown signal observations. This study employs LISA’s science requirement of maintaining a duty cycle of at least 75% to evaluate the worst-case impact of data gaps, and uses massive black hole binary catalogs to assess the average effects. Our findings indicate that, on average, data gaps increase parameter estimation errors by approximately 2.1 times for the (2, 2) mode and by about 1.6 times for the (3, 3) mode. Joint observation is commonly employed to alleviate the impact of data gaps. Similarly, we have evaluated the effects of joint observation with two configurations, Taiji-LISA and Taiji-TianQin, which demonstrate notable mitigation of the effects of data gaps. This work provides a quantitative assessment of data gaps on ringdown signals and highlights the significance of joint observation.

Gravitational waves, first predicted by Albert Einstein within the framework of general relativity, were confirmed in 2015 by the LIGO/Virgo Collaboration, marking a pivotal breakthrough in astrophysics. Despite this achievement, a key challenge remains in distinguishing true gravitational wave signals from noise artifacts, or “glitches”, which can distort data and affect the quality of observations. Current state-of-the-art methods, such as the Q-transform, are widely used for signal processing, but face limitations when addressing certain types of signals. In this study, we investigate the wavelet scattering transform (WST), a recent signal analysis method, as a complementary approach. Theoretical motivation for the WST arises from its stability under signal deformations and its equivariance properties, which make it particularly suited for the complex nature of gravitational wave data. Our experiments on the LIGO O1a dataset show that the WST simplifies classification tasks and enables the use of more efficient architectures compared to traditional methods. Furthermore, we explore the potential benefits of integrating the WST with the Q-transform, demonstrating that ensemble methods exploiting both techniques can capture complementary features of the signal and improve overall performance. This work contributes to advancing machine learning applications in gravitational wave analysis, introducing refined preprocessing techniques that improve signal detection and classification.

Motivated by the parametrization invariance of cosmological Lagrangians and their equivalence to systems describing the motion of particles in curved backgrounds, we identify the phase space analogue of the notion of proper time. We define the corresponding quantum operator, which results in being canonically conjugate to that of the vanishing Hamiltonian. In the context of particle dynamics, this leads to an uncertainty relation of the form $\mathrm{\Delta }{E}_0\mathrm{\Delta }T\ge \hslash$, where $E_0$ is the rest energy of the particle. By studying the nonrelativistic limit, we show that the action of the operator reduces to multiplication by the classical time coordinate. Finally, we derive the generic expression for the introduced time variable in the cosmological setting.

The sum of neutrino masses can be measured cosmologically, as the sub-eV particles behave as “hot” dark matter whose main effect is to suppress the clustering of matter compared to a universe with the same amount of purely cold dark matter. Current astronomical data provide an upper limit on $\sum m_{\nu }$ between 0.07–0.12 eV at 95% confidence, depending on the choice of data. This bound assumes that the cosmological model is $\mathrm{\Lambda }$ Cold Dark Matter ($\mathrm{\Lambda }\mathrm{CDM}$), where dark energy is a cosmological constant, the spatial geometry is flat, and the primordial fluctuations follow a pure power law. Here, we update studies on how the mass limit degrades if we relax these assumptions. To existing data from the Planck satellite we add new gravitational lensing data from the Atacama Cosmology Telescope, the new Type Ia supernova sample from the $\mathrm{Pantheon}+\text{survey}$, and baryonic acoustic oscillation (BAO) measurements from the Sloan Digital Sky Survey and the Dark Energy Spectroscopic Instrument. Using our fiducial data combination, described in the appendix, we find the neutrino mass limit is stable to most model extensions, with such extensions degrading the limit by less than 10%. We find a broadest bound of $\sum m_{\nu }<0.19\mathrm{eV}$ at 95% confidence for a model with dynamical dark energy, although this scenario is not statistically preferred over the simpler $\mathrm{\Lambda }\mathrm{CDM}$ model.

Electromagnetic fields surrounding pulsars may source coherent ultralight axion signals at the known rotational frequencies of the neutron stars, which can be detected by laboratory experiments (e.g., pulsarscopes). As a promising case study, we model axion emission from the well-studied Crab pulsar, which would yield a prominent signal at $f\approx 29.6\mathrm{Hz}$ regardless of whether the axion contributes to the dark matter abundance. We estimate the relevant sensitivity of future axion dark matter detection experiments such as DMRadio-GUT, Dark SRF, and CASPEr, assuming different magnetosphere models to bracket the uncertainty in astrophysical modeling. For example, depending on final experimental parameters, the Dark SRF experiment could probe axions with any mass $m_a\ll {10}^{-13}\mathrm{eV}$ down to $g_{a\gamma \gamma }\sim 3\times {10}^{-13}{\mathrm{GeV}}^{-1}$ with one year of data and assuming the vacuum magnetosphere model. These projected sensitivities may be degraded depending on the extent to which the magnetosphere is screened by charge-filled plasma. The promise of pulsar-sourced axions as a clean target for direct detection experiments motivates dedicated simulations of axion production in pulsar magnetospheres.

For the first time, we use relativistic mean-field approximation with density-dependent couplings, adjusted by the Density-Dependent Meson-Exchange 2 (DDME2) parameterization, to investigate the effects of dark matter on supernova remnants. We calculate the nuclear equation of state for nuclear and dark matter separately, under the thermodynamic conditions related to the evolution of supernova remnants. A mirrored model is adopted for dark matter, and its effect on remnant matter is studied using a two-fluid scenario. At each stage of the remnant evolution, we assume that dark and ordinary matter have the same entropy and lepton fraction, and a fixed proportion of dark matter mass fraction is added to the stellar matter to observe its effects on some microscopic and macroscopic properties of the star. We observe that dark matter in the remnant core reduces the remnant’s maximum mass, radius, and tidal deformability. Moreover, dark matter heats the remnant matter and alters particle distributions, thereby decreasing its isospin asymmetry and increasing the sound speed through the matter.

A neutron whispering gallery state is a quantum state localized on a material surface bound by the centrifugal force and the material potential. Precise measurements of such quantum states enable tests of quantum mechanics in noninertial frames, characterization of the surface potential, and searches for hypothetical short-range interactions at the nanometer scale. We observed a neutron whispering gallery state on a ${\mathrm{SiO}}_2$ concave mirror using a pulsed cold neutron beam. The measured results agree with theoretical calculations within 1.9% for the centrifugal acceleration $a\approx 7\times {10}^7\mathrm{m}/{\mathrm{s}}^2$, which is due to unmodeled deviations of the shape of the concave mirror edge from an ideal one. We found that the sensitivity itself was $1\times {10}^{-4}$, which is two orders of magnitude better than the above agreement.

The semi-inclusive decay processes of a top quark into a charged pseudoscalar meson and a jet are studied within the framework of QCD factorization. The leading power of the decay matrix elements can be factorized into heavy-to-light quark transition current and a hadron matrix element up to next-to-leading-order QCD corrections. We calculate one-loop virtual corrections together with real gluon emission corrections at the ${\alpha }_s$ order. The numerical results of the branching ratios are presented for the sum of two- and three-body decays. We also study the energy cutoff dependence of the gluon jet. These processes are hopeful to be detected in near future experiments, which can serve as probes for new physics.

We present a general method to determine the probability that stochastic Monte Carlo data, in particular those generated in a lattice QCD calculation, would have been obtained were that data drawn from the distribution predicted by a given theoretical hypothesis. Such a probability, or $p$-value, is often used as an important heuristic measure of the validity of that hypothesis. The proposed method offers the benefit that it remains usable in cases where the standard Hotelling $T^2$ methods based on the conventional ${\chi }^2$ statistic do not apply, such as for uncorrelated fits. Specifically, we analyze $q^2$, defined as the correlated ${\chi }^2$ statistic obtained using an arbitrary covariance matrix estimator, and show how to use the bootstrap as a data-driven method to determine the expected distribution of $q^2$ for a given hypothesis with minimal assumptions. This distribution can then be used to determine the $p$-value for a fit to the data. We also describe a bootstrap approach for quantifying the impact upon this $p$-value of estimating population parameters from a single ensemble of $N$ samples. The overall method is accurate up to a $1/N$ bias which we do not attempt to quantify.

We investigate the effects of temperature $T$ and external magnetic fields $eB$ on the chiral condensates and screening masses of neutral pseudoscalar mesons, including ${\pi }^0$, $K^0$, and ${\eta }_{s\overline{s}}^0$, in ($2+1$)-flavor lattice QCD with physical quark masses. The chiral condensates are intrinsically connected to the screening masses via Ward-Takahashi identities, with the latter characterizing the inverse of the spatial correlation length in the pseudoscalar channel. Using highly improved staggered quark (HISQ), we perform simulations on lattices with temporal extents $N_{\tau }=8$, 12, 16 and an aspect ratio of 4, covering five temperatures from 145 MeV to 166 MeV. For each temperature, eight magnetic field strengths are simulated, reaching up to $eB\sim 0.8{\mathrm{GeV}}^2$. These simulations allow us to provide continuum estimates for the chiral condensates and screening masses. We observe intricate behavior in the light ($ud$), strange-light ($ds$), and strange ($s$) quark condensates as functions of the magnetic field and temperature, reflecting the competition between magnetic catalysis and inverse magnetic catalysis effects. This complex behavior is also mirrored in the screening masses of the neutral pseudoscalar mesons. Notably, the screening masses of ${\pi }^0$ and $K^0$ exhibit a nonmonotonic dependence on $eB$, closely following the variations in their corresponding chiral condensates. Meanwhile, the screening mass of ${\eta }_{s\overline{s}}^0$ decreases monotonically with increasing $eB$. These findings provide valuable insights for understanding the behavior of QCD in a thermomagnetic medium and can serve as benchmarks for low-energy QCD models and effective theories.

We show that placing a radioactive source such as ${}^{51}\mathrm{Cr}$ near a liquid xenon detector may allow us to detect the contribution induced by the anapole moment to neutrino-electron scattering in the Standard Model (SM) at the $1-2\sigma$ level. Although the anapole moment of neutrinos induces a scattering rate with the same spectral shape as the neutral and charged current contributions, exposures of $\sim 60\mathrm{ton}\times \mathrm{source}$ run at XENONnT or XLZD may be enough to accumulate sufficient statistics for a detection. We also discuss a simple model where the anapole moment of neutrinos is enhanced or decreased with respect to the SM expectation, further demonstrating how a potential measurement of the anapole moment of neutrinos would allow us to constrain new physics.

RED-100 is a two-phase liquid xenon time projection chamber with an active volume containing 126 kg of liquid xenon. The detector was exposed to an antineutrino flux of about $1.4\times {10}^{13}{\mathrm{cm}}^{-2}{\mathrm{s}}^{-1}$ at a distance of 19 m from the 3.1 GW Kalinin nuclear power plant reactor core. The comparison of data from $331\mathrm{kg}·\mathrm{days}$ with the reactor on and $106\mathrm{kg}·\mathrm{days}$ with the reactor off shows no statistically significant excess and the constraint on coherent elastic scattering of antineutrinos off xenon nuclei cross section is given.

We study mixed state entanglement measures in a higher dimensional $T\overline{T}$ deformed field theory at finite temperature. The holographic dual is described by ${\mathrm{AdS}}_{d+1}$ black brane geometry with a finite cutoff. We compute the entanglement wedge cross section (EWCS), proposed to be dual to entanglement of purification and holographic entanglement negativity (HEN) for striplike subsystems. The behavior of EWCS and HEN is studied across different regimes of temperature and deformation parameter. It is observed that the deformation and temperature exhibit similar effects on these two entanglement measures. Increasing the deformation leads to a decrease in the entanglement between the subsystems.