An analysis is presented based on models of the intrinsic transverse momentum (intrinsic $k_{\mathrm{T}}$) of partons in nucleons by studying the dilepton transverse momentum in Drell-Yan events. Using parameter tuning in event generators and existing data from fixed-target experiments and from hadron colliders, our investigation spans 3 orders of magnitude in center-of-mass energy and 2 orders of magnitude in dilepton invariant mass. The results show an energy-scaling behavior of the intrinsic $k_{\mathrm{T}}$ parameters, independent of the dilepton invariant mass at a given center-of-mass energy.

We propose the dressing factors for the scattering of massive particles on the worldsheet of mixed-flux ${\mathrm{AdS}}_3\times S^3\times T^4$ superstrings, in the string and mirror kinematics. The proposal passes all self-consistency checks in the both kinematics, including for bound states. It matches with perturbative and semiclassical computations from the string sigma model, and with its relativistic limit.

We obtain a formal integral solution to the $3+1\mathrm{D}$ Boltzmann equation in relaxation-time approximation. The gradient series obtained from this integral solution contains exponentially decaying nonhydrodynamic terms. It is shown that this gradient expansion can have a finite radius of convergence under certain assumptions of analyticity. We then argue that, in the relaxation-time model, proximity to local thermal equilibrium is not necessary for the system to be described by hydrodynamic equations.

This paper investigates the effects of noise on the diagnostics of quantum chaos, focusing on three primary tools: the spectral form factor (SFF), Krylov complexity, and out-of-time correlators (OTOCs). Utilizing a closed quantum system model with white noise, we demonstrate that increasing noise strength leads to an exponential suppression of these diagnostic measures. Specifically, our findings reveal that in the strong noise limit, the SFF, two-point correlation function, and OTOCs become ineffective in distinguishing chaotic behavior. The SFF is particularly impacted, exhibiting a significant decay that obscures its ability to identify quantum chaos. This study highlights the challenges posed by environmental noise in accurately diagnosing quantum chaotic systems and suggests that traditional methods may require adaptation to remain effective in realistic open quantum systems. Our results underscore the need for further research into robust diagnostic techniques that can account for noise-induced effects in quantum chaotic systems.

We demonstrate the presence of multimode entanglement in the vacuum state of a free, massless scalar quantum field in four-dimensional flat spacetime between two sets of field modes, each contained within a spacetime region that is causally disconnected from the other. This is true despite the fact that entanglement between pairs of individual field modes is sparse and appears only when the two individual modes are carefully selected. Our results reveal that, while entanglement between individual modes is limited, bipartite multimode entanglement in quantum field theory is ubiquitous. We further argue that such multimode entanglement is operationally extractable, and it forms the basis of the entanglement commonly discussed in entanglement harvesting protocols.

We elaborate on a recently proposed geometric framework for scalar effective field theories. Starting from the action, a metric can be identified that enables the construction of geometric quantities on the associated functional manifold. These objects transform covariantly under general field redefinitions that relate different operator bases, including those involving derivatives. We present a novel geometric formula for the amplitudes of the theory, where the vertices in Feynman diagrams are replaced by their geometrized counterparts. This makes the on-shell covariance of amplitudes manifest, providing the link between functional geometry and effective field theories.

We revisit the problem of spontaneous symmetry breaking (SSB), its restoration, and phase transition for a self-interacting quantum scalar field in a general curved background, at zero and finite temperature. To the best of our knowledge, most of the earlier computations in this context have been done in the linear order in curvature, which may not be very suitable for the Ricci flat spacetimes. One of our objectives is to see whether the higher-order terms can bring in qualitatively new physical effects, and thereby attempting to fill in this gap in the literature. We use Bunch and Parker’s local momentum space representation of the Schwinger-DeWitt expansion of the Feynman propagator. Such expansion, being based upon the local Lorentz symmetry of spacetime, essentially probes the leading curvature correction to short scale, ultraviolet quantum processes. We compute the renormalized, background spacetime curvature (up to quadratic order) and temperature-dependent one-loop effective potential for ${\varphi }^4$ plus ${\varphi }^3$ self-interaction. In particular for the de Sitter spacetime, we have shown for the ${\varphi }^4$-theory that we can have SSB even with a positive rest mass squared and positive nonminimal coupling, at zero temperature. This cannot be achieved by the linear curvature term alone and the result remains valid for a very large range of renormalization scale. Such SSB will generate a field mass that depends upon the spacetime curvature as well as the nonminimal coupling. For a phase transition, we have computed the leading curvature correction to the critical temperature. At finite temperature, symmetry restoration is demonstrated. We also extend some of the above results to two-loop level. The symmetry breaking in de Sitter at two loop remains present. We have further motivated the necessity of treating this problem nonperturbatively in some instances.

In this work, we introduce an explicit expression for the inverse of the symmetric bilinear form of Virasoro Verma modules, the so-called Shapovalov form, in terms of singular vector operators and their conformal dimensions. Our proposed expression also determines the resolution of the identity for Verma modules of the Virasoro algebra, and can be thus employed in the computation of Virasoro conformal blocks via the sewing procedure.

We provide a mode-sum prescription to directly compute the renormalized stress-energy tensor (RSET) for scalar fields in the Boulware vacuum. The method generalizes the recently developed extended coordinate method which was previously only applicable to Hartle-Hawking states. We exhibit the accuracy and efficiency of the method by calculating the RSET in subextremal and extremal Reissner-Nordström spacetimes. We find numerical evidence for the regularity of the RSET at the extremal horizon regardless of the field mass and its coupling. We employ our numerical results of the RSET to source the semiclassical Einstein equations, demonstrating that if the RSET is considered as a static perturbation, it will either deextremalize the black hole, or convert it into a horizonless object.

In the context of AdS/CFT duality, we study semiclassical stationary rotating AdS black holes with nontrivial quantum hair in three and five dimensions. We construct these solutions by perturbing the Bañados-Teitelboim-Zanelli (BTZ) black hole and the five-dimensional Myers-Perry AdS black hole according to holographic semiclassical equations. In the three-dimensional case, the vacuum expectation value of the stress-energy tensor diverges as $\sim 1/{\lambda }^n$ ($n=1$, 2) along a radial null geodesic as the affine parameter $\lambda$ approaches zero at the Cauchy horizon, depending on the type of perturbation. In the five-dimensional case, most hairy solutions exhibit strong divergences, either in the stress-energy tensor or in the parallelly propagated Riemann components, along the radial null geodesic crossing the Cauchy horizon. Nevertheless, there exists a specific class of semiclassical solutions that retain a $C^0$-regular Cauchy horizon, where perturbations remain bounded. For extremal black holes, the vacuum expectation value of the stress-energy tensor diverges along a radial null geodesic transverse to the event horizon in both three and five dimensions, even though all components of the perturbed metric vanish in this limit.

The symmetron is a light scalar which provides a screening mechanism so as to evade the strong constraints from local gravity tests. To achieve this goal, a $Z_2$ symmetry is imposed on the symmetron model. In this paper, we introduce a new symmetron Chern-Simons-like gravitational interaction which is $Z_2$ invariant but breaks the parity symmetry explicitly. As a result, it is found that this coupling can generate gravitational wave (GW) amplitude birefringence when GWs propagate over the symmetron backgrounds. Because of the matter density difference, the symmetron profile changes significantly when entering the galaxy, so we need to discuss the extragalactic and galactic situations separately. On the one hand, the cosmological symmetron field follows the adiabatic solution, which induces a parity-violating GW amplitude correction with its exponent proportional to the GW frequency and the traveling distance. On the other hand, the symmetron takes the screening solution within the Milky Way, and the generated GW birefringence is only a function of the GW frequency. By further comparing these two contributions, we find that the extragalactic symmetron field produces the dominant birefringence effects. Finally, with the latest GW data from LIGO-Virgo-Kagra, we place a reasonable constraint on the parity-violating coupling parameter in this symmetron model.

Gravitational lensing by compact, small-scale intervening masses causes frequency-dependent distortions to gravitational-wave events. The optimal signal-to-noise ratio (SNR) is often used as a proxy for the detectability of exotic signals in gravitational-wave searches. In reality, the detectability of such signals in a matched-filtering search requires comprehensive consideration of match-filtered SNR, signal-consistency test value, and other factors. In this work, we investigate for the first time the detectability of lensed gravitational waves from compact binary coalescences with a match-filtering search pipeline, GstLAL. Contrary to expectations from the optimal SNR approximation approach, we show that the strength of a signal (i.e., higher optimal SNR) does not necessarily result in higher detectability. We also demonstrate that lensed gravitational waves with wave optic effects can suffer significantly, from 90% (unlensed) to $<1\%$ (lensed) detection efficiency, due to downranking by the signal-consistency test values. These findings stress the need to extend current template banks to effectively search for lensed gravitational waves and to reassess current constraints on compact dark matter scenarios.

We report on the potential occurrence of a numerical instability in the long-time simulation of black holes using the Baumgarte-Shapiro-Shibata-Nakamura formulation of numerical relativity, even in the simple setup of a Schwarzschild black hole. Through extensive numerical experiments, we identify that this “late-time instability” arises from accumulated violations of the momentum constraint. To address this issue, we propose two modified versions of the so-called conformal covariant Z4 scheme, designed to propagate momentum constraint violations without damping. Our results demonstrate that these alternative formulations, which we refer to as CCZ4’ and CCZ3, effectively resolve the late-time numerical instability not only in Schwarzschild spacetimes but also in black hole spacetimes with matter fields. Notably, by preventing damping of the momentum constraint violation, the Hamiltonian constraint damping can be significantly increased, which plays a crucial role in stabilizing long-term evolution in our proposed schemes.

The Gibbons-Werner method, which employs the Gauss-Bonnet theorem and the optical/Jacobi metric to compute deflection angles in the weak-field regime, has become widely popular in recent years. Werner extended this method to stationary spacetimes, where the optical/Jacobi metric takes the form of a Finsler metric of Randers type, by adopting an osculating Riemannian metric. Werner’s method is particularly valuable as it provides a concise expression for the deflection angle, holds potential for application to gravitational lensing in Finsler spaces beyond the Randers type, and may stimulate the broader application of Finsler geometry across diverse fields. However, it has not been widely adopted due to the cumbersome calculations involved in the conventional coordinates $(r,\varphi )$. This paper aims to reduce the computational burden of Werner’s method, thereby making it a more practical and accessible approach. To this end, we introduce Cartesian-like coordinates $(X,Y)$ to construct the osculating Riemannian metric and calculate the deflection angle using the Gauss-Bonnet theorem. We demonstrate the effectiveness of our method by computing the deflection of massive particles in Kerr spacetime, rotating Bardeen (Hayward) regular spacetime and Teo rotating wormhole spacetime. Future research aims to extend Werner’s method to the study of gravitational lensing in Finsler spaces beyond the Randers type. Although this paper focuses on Randers metrics, it provides a foundation for such an extension.

Working in momentum space and at linear order in the gravitational coupling, we derive the most general class of energy-momentum tensors associated with a given multipolar structure of the spacetime in arbitrary dimensions, and built out of a mass and an angular momentum, at any order in the spin expansion. In this formalism, we are able to derive directly the full multipolar structure of any solution from the multipole expansion of the energy-momentum tensor, in complete analogy to Newtonian gravity. In particular, we identify the recurrence relations that allow obtaining the multipolar structure of the Kerr and the Myers-Perry black hole solutions, defining source multipoles in a general relativity context for the first time. For these solutions, we are able to resum the energy-momentum tensor in momentum space at all orders in the angular momentum, and compute its real-space version. In the Kerr case, we exactly obtain the matter source found by Israel, namely an equatorial, pressureless thin disk rotating at superluminal speed. For Myers-Perry in five dimensions, the matter distribution is a three-ellipsoid in four spatial dimensions with nontrivial stresses. Remarkably, for any dimensions, the matter configuration is a lower-dimensional distribution, which has the same singularity structure as the fully nonlinear black-hole solution. Our formalism underscores the advantage of working in momentum space to generate nontrivial matter sources for nonlinear spacetimes, and could be used to construct regular nonexotic matter configurations that source spinning black hole solutions or horizonless compact objects with the same multipolar structure as black holes.

We derive the Hamiltonian function for extended teleparallel theories of gravity in their covariant formulation. In particular, we present the Hamiltonian for $f(T)$ gravity and new general relativity. From this, we obtain the related Hamilton equations, which are presented both in covariant formulation and Weitzenböck gauge. In this framework, teleparallel equivalent to general relativity, its $f(T)$ extension, and new general relativity can be compared. We find that $f(T)$ and new general relativity consistently reduce to the Teleparallel Equivalent to general relativity, while significant differences appear comparing the Hamilton equations of $f(T)$ with $f(R)$ gravity.

We study a primordial black hole (PBH) formation model based on the framework of the inhomogeneous Affleck-Dine (AD) mechanism, which can explain the seeds of supermassive black holes (SMBHs). This model predicts strong clustering of SMBHs that is inconsistent with the observation of angular correlation of quasars. In this paper, we propose a modified model that can significantly reduce the PBH clustering on large scales by considering a time-dependent Hubble-induced mass during inflation. The quasar angular correlation is suppressed by the large Hubble-induced mass in the early stage of inflation while the small Hubble-induced mass in the late stage leads to the AD field fluctuations large enough for PBH formation as in the original model. As a result, the modified scenario can successfully explain the seeds of SMBHs.

Gravitational waves induced by primordial perturbations serve as crucial probes for studying the early Universe, providing a significant window into potential new physics during cosmic evolution. Due to the potentially large amplitudes of primordial perturbations on small scales, the contributions of high-order cosmological perturbations (CPs) are highly significant. We propose a vertex approach applicable to the study of induced gravitational waves for arbitrary higher orders. Using the vertex approach and tree diagrams, we can directly derive the explicit expressions of higher-order induced gravitational waves without involving the complex and lengthy calculations of higher-order CPs. Correlations between different tree diagrams correspond to the loop diagrams of two-point correlation functions of induced gravitational waves. Our investigation reveals that one-particle reducible diagrams impact tensor-scalar-induced gravitational waves while leaving scalar-induced gravitational waves unaffected.

Self-gravitating condensates have been proposed as potential candidates for modeling dark matter. In this paper, we numerically investigate the dynamics of dark matter utilizing the merging of self-gravitating condensates. We have used the Gross-Pitaevskii-Poisson model and identified distinct turbulent regimes based on the merging speed of the condensate. As a result of collision, we notice the appearance of various dark soliton-mediated instabilities that finally lead to the turbulent state characterized by Kolmogorov-like turbulence scaling ${ϵ}_{\mathrm{kin}}^i\sim k^{-5/3}$ in the infrared and ${ϵ}_{\mathrm{kin}}^i\sim k^{-3}$ in the ultraviolet regions. The compressible spectrum suggests weak-wave turbulence. The turbulent fluctuations in the condensate cease as the vortices formed via soliton decay are expelled to the condensate’s periphery, manifested in the transferring of kinetic energy from incompressible and compressible flows to the quantum pressure energy. We also establish the significant role played by the self-gravitating trap in determining the distribution of compressible kinetic energy and the resulting density waves, which differ markedly from those observed in atomic condensates under harmonic confinement. Our study may offer valuable insights into the merging of binary stars and open new avenues for understanding the structure and dynamics of the dark matter through self-gravitating condensate.

We present cosmological constraints from weak lensing with the Subaru Hyper Suprime-Cam (HSC) first-year data, using a simulation-based inference (sbi) method. We explore the performance of a set of higher-order statistics (HOS) including the Minkowski functionals, counts of peaks and minima, and the probability distribution function and compare them to the traditional two-point statistics. The HOS, also known as non-Gaussian statistics, can extract additional non-Gaussian information that is inaccessible to the two-point statistics. We use a neural network to compress the summary statistics, followed by an sbi approach to infer the posterior distribution of the cosmological parameters. We apply cuts on angular scales and redshift bins to mitigate the impact of systematic effects. Combining two-point and non-Gaussian statistics, we obtain $S_8\equiv {\sigma }_8\sqrt{{\mathrm{\Omega }}_m/0.3}=0.804_{-0.040}^{+0.041}$ and ${\mathrm{\Omega }}_m=0.344_{-0.090}^{+0.083}$, similar to that from non-Gaussian statistics alone. These results are consistent with previous HSC analyses and Planck 2018 cosmology. Our constraints from non-Gaussian statistics are $\sim 25\%$ tighter in $S_8$ than two-point statistics, where the main improvement lies in ${\mathrm{\Omega }}_m$, with $\sim 40\%$ tighter error bar compared to using the angular power spectrum alone ($S_8=0.766_{-0.056}^{+0.054}$ and ${\mathrm{\Omega }}_m=0.365_{-0.141}^{+0.148}$). We find that, among the non-Gaussian statistics we studied, the Minkowski functionals are the primary driver for this improvement. Our analyses confirm the sbi as a powerful approach for cosmological constraints, avoiding any assumptions about the functional form of the data’s likelihood.