Bubble chambers are promising technologies for detecting low-energy nuclear recoils from the elastic scattering of dark matter particle candidates. Bubble nucleation occurs when the energy deposition exceeds a specific threshold defined traditionally by the “heat-spike” Seitz threshold. In this paper, we report on a physical model that can account for observed discrepancies between the current Seitz model and the measured nucleation efficiency of low-energy nuclear recoils, which is necessary for interpreting dark matter signals. In our work, we combine molecular dynamics and Monte Carlo simulations together with the Lindhard model to predict bubble nucleation efficiency and energy thresholds for ${\mathrm{C}}_3{\mathrm{F}}_8$, ${\mathrm{CF}}_3\mathrm{I}$, and xenon with enhanced accuracy over the Seitz model when compared to existing experimental data. We use our model to determine the effect on cross-section limits for spin-dependent and spin-independent interactions and compare it to the current PICO dark matter experiment. Our technique can also be applied to estimate the efficiency of future target fluids where no experimental data are available. As an example, we predict the nucleation efficiency, the energy threshold, and the cross-section limits in the spin-independent channel for the Scintillating Bubble Chamber experiment filled with superheated liquid argon.

In this paper, we introduce a simple and efficient approach for the general reduction of one-loop integrals. Our method employs the introduction of an auxiliary vector and the identification of the tensor structure as an auxiliary propagator. This key insight allows us to express a wide range of one-loop integrals, encompassing both tensor structures and higher poles, in the Baikov representation. By establishing an integral-by-parts relation, we derive a recursive formula that systematically solves the one-loop reduction problem, even in the presence of various degenerate cases. Our proposed strategy is characterized by its simplicity and effectiveness, offering a significant advancement in the field of one-loop calculations.

In this work, we have exclusively employed the linear stability analysis at ultrahigh boost on two well-known stable-causal theories—second-order Müller-Israel-Stewart and first-order Bemfica-Disconzi-Noronha-Kovtun, to identify the region of parameter space over which they are frame-invariantly stable and obey causal signal propagation. It has been shown for these two theories that at near-luminal boost, stability criteria alone can provide the causality constraints on transport coefficients, which are identical to the asymptotic causality conditions, without actually going to the asymptotic limit of the theories. The analysis indicates an alternative approach to derive the causality constraints, which is more appropriate for low-energy effective theories like relativistic hydrodynamics.

In this paper we consider description of kaon-antikaon interference in the context of a theory with deformed $\mathcal{C}\mathcal{P}\mathcal{T}$ symmetry. In the case of such theoretical models, deviations from the standard $\mathcal{C}\mathcal{P}\mathcal{T}$ invariance is related to the momentum carried by the particles; in particular the rest masses of particles and antiparticles are equal. We find that the decay intensity of kaon-antikaon pair has three contributing terms: the correct-parity, the wrong-parity, and the interference between them, all of which are affected by deformation. Using the fact that the presence of such terms was not observed we estimate, under plausible assumptions, the magnitude of deformation parameter $\kappa \gtrsim {10}^{17}\mathrm{GeV}$ at the LHC energy. This limit can be possibly improved to values closer to the expected Planck mass scale $\kappa \gtrsim {10}^{18}\mathrm{GeV}$ using a next-generation collider with energy larger by an order of magnitude. This raises hopes that the effect, if it exists, could be detected in future accelerator experiments. Uncertainties of the energy measurement and time resolution are important for accuracy of these predictions.

A light pseudoscalar $A$ in the sufficient large $\tan \beta$ region of type-I two-Higgs-doublet model can be naturally a long-lived particle. We focus on $H^{\pm }A$, $HA$, and $AA$ pair productions via the electroweak processes mediated by the bosons at the LHC, including $pp\to W^{\pm }/Z\to H^{\pm }/HA$ and $pp\to h\to AA$ at the 14 TeV LHC. The possibility of probing $A$ as a LLP at the FASER-2, FACET, MoEDAL-MAPP-2, and MATHUSLA is discussed. We find that FASER-2 fails to probe any parameter space within $0.2\mathrm{GeV}<m_A<10\mathrm{GeV}$ for all the considered processes. For $130<m_{H\pm }=m_H<400\mathrm{GeV}$, FACET, MoEDAL-MAPP-2, and MATHUSLA can probe $\tan \beta \lesssim {10}^{4-6}$ for $m_A\lesssim 3\mathrm{GeV}$, and $\tan \beta \lesssim {10}^{6-8}$ for $3\mathrm{GeV}\lesssim m_A<10\mathrm{GeV}$ from $pp\to W^{\pm }/Z\to H^{\pm }/ZA$ processes. And $pp\to h\to AA$ process covers similar parameter space. All processes can surpass the current limits.

We discuss various formal aspects of contour deformations used to alleviate sign problems; most importantly, relating these contour deformations to a certain convex optimization problem. As a consequence of this connection we describe a general method for proving upper bounds on the average phase achievable by the contour deformation method. Using this method we show that Abelian lattice Yang-Mills in two spacetime dimensions possesses, for many values of the complex coupling, an exponential sign problem that cannot be removed via any contour deformation.

This paper details the first application of a software tagging algorithm to reduce radon-induced backgrounds in liquid noble element time projection chambers, such as XENON1T and XENONnT. The convection velocity field in XENON1T was mapped out using ${}^{222}\mathrm{Rn}$ and ${}^{218}\mathrm{Po}$ events, and the rms convection speed was measured to be $0.30\pm 0.01\mathrm{cm}/\mathrm{s}$. Given this velocity field, ${}^{214}\mathrm{Pb}$ background events can be tagged when they are followed by ${}^{214}\mathrm{Bi}$ and ${}^{214}\mathrm{Po}$ decays, or preceded by ${}^{218}\mathrm{Po}$ decays. This was achieved by evolving a point cloud in the direction of a measured convection velocity field, and searching for ${}^{214}\mathrm{Bi}$ and ${}^{214}\mathrm{Po}$ decays or ${}^{218}\mathrm{Po}$ decays within a volume defined by the point cloud. In XENON1T, this tagging system achieved a ${}^{214}\mathrm{Pb}$ background reduction of ${6.2}_{-0.9}^{+0.4}\%$ with an exposure loss of $1.8\pm 0.2\%$, despite the timescales of convection being smaller than the relevant decay times. We show that the performance can be improved in XENONnT, and that the performance of such a software-tagging approach can be expected to be further improved in a diffusion-limited scenario. Finally, a similar method might be useful to tag the cosmogenic ${}^{137}\mathrm{Xe}$ background, which is relevant to the search for neutrinoless double-beta decay.

Let a physical event constitute a simple loop in spacetime. This in turn calls for a generalized loop line element ($={\mathrm{distance}}^2$ between two neighboring loops) capable of restoring, at the shrinking loop limit, the special relativistic line element ($={\mathrm{distance}}^2$ between the two neighboring centers-of-mass, respectively). Sticking at first stage to a flat Euclidean/Minkowski background, one is led to such a preliminary loop line element, where the role of coordinates is played by the oriented cross sections projected by the loop event. Such cross sections are generically center-of-mass independent, unless (owing to a topological term) the loop events are intrinsically wrapped around a Kaluza-Klein–like compact fifth dimension. Serendipitously, it is the Kaluza-Klein ingredient which, on top of its traditional assignments, is shown to govern the extension of the Pythagoras theorem to loop space. Associated with $M_4\otimes S_1$ is then a ten-dimensional loop spacetime metric, whose four-dimensional center-of-mass core term is supplemented by a six-dimensional Maxwell-style fine structure. The imperative inclusion of a positive (say Nambu-Goto) string tension within the framework of loop special relativity is fingerprinted by a low periodicity breathing mode. Nash global isometric embedding is conjectured to play a major role in the construction of loop general relativity.

A quantum theory of gravity implies a fine-grained structure of spacetime, which can be conveniently modeled as some form of “pixelation” at the Planck scale, with potentially observable consequences. In this work, we build upon previous results to investigate the effect of pixelation on the quantum vacuum, making use of the framework of doubly special relativity (DSR). At the center of the DSR approach is an observer-dependent length scale, defining the pixelation of spacetime. A key feature of quantum field theory in DSR is the dispersive nature of the vacuum state and the associated appearance of curvature in momentum space. As a result, the standard treatment of the renormalized stress-energy-momentum tensor acquires correction terms. As an illustration, we present here a calculation of the thermal vacuum and modified Casimir effect, using both modified propagators and momentum measures. We choose a consistent choice of momentum space metric that both generates the modified dispersion relations we use and preserves the Lorentz invariant character of the results obtained. Put together this constitutes a consistent calculation framework we can apply to other more complex scenarios.

We investigate the gravitational anomaly vertex $⟨TT{J}_5⟩$ (graviton—graviton—axial current) under conditions of finite density and temperature. Through a direct analysis of perturbative contributions, we demonstrate that neither finite temperature nor finite fermion density affects the gravitational chiral anomaly. These results find application in several contexts, from topological materials to the early Universe plasma. They affect the decay of any axion or axionlike particle into gravitational waves, in very dense and hot environments.

The inspiral-merger-ringdown consistency test (IMRCT) is one among a battery of tests of general relativity (GR) employed by the LIGO-Virgo-KAGRA (LVK) Collaboration. It is used to search for deviations from GR in detected gravitational waves (GWs) from compact binary coalescences (CBCs) in a model-agnostic way. The test compares source parameter estimates extracted independently from the inspiral and postinspiral portions of the CBC signals and, therefore, crucially relies on the accurate modeling of the waveform. Current implementations of the IMRCT routinely use quasicircular waveforms, under the assumption that the residual eccentricity of the binary when the emitted GWs enter the frequency band of the LVK detector network will be negligible. In this work, we perform a detailed study to investigate the typical magnitudes of this residual eccentricity that could potentially lead to spurious violations of the IMRCT. To that end, we conduct injection campaigns for a range of eccentricities and recover with both quasicircular and eccentric waveforms. We find that an eccentric GW signal from a GW150914-like system with eccentricity $e_{\mathrm{gw}}\gtrsim 0.04$ at an orbit averaged frequency $⟨f_{\mathrm{ref}}⟩=25\mathrm{Hz}$ breaks the IMRCT if recovered with quasicircular waveforms at $\gtrsim 68\%$ CL. The violation becomes more severe ($\gtrsim 90\%$ confidence) for $e_{\mathrm{gw}}=0.055$ at $⟨f_{\mathrm{ref}}⟩=25\mathrm{Hz}$. On the other hand, when eccentric waveforms are used, the IMRCT remains intact for all eccentricities considered. We also briefly investigate the effect of the magnitude and orientation (aligned/antialigned) of the component spins of the binary on the extent of the spurious violations of the IMRCT. Our work, therefore, demonstrates the need for accurate eccentric waveform models in the context of tests of GR.

A gravitational field can cause a rotation of the polarization plane of light. This phenomenon is known as the gravitational Faraday effect. It arises due to different spin-orbit interactions of left- and right-handed circularly polarized components of light. Such an interaction also causes transverse displacement in the light trajectory, in opposite directions for each component. This phenomenon is known as the gravitational spin-Hall effect of light. We study these effects in a local inertial frame in arbitrary vacuum spacetime and show that they are observer dependent and arise due to interaction of light polarization with a local gravitomagnetic field measured by the observer. Thus, to address the effects to a gravitational field alone, one has to consider zero angular momentum observers.

For a large class of black holes, we show that the sum of thermodynamic quantities over all the horizons is determined by the asymptotic data at infinity. For the Kerr-Newman metric, this proves a recent numerical observation by Hristov. We propose a new method to compute the sum of the entropies using a generalized Smarr formula. The higher-curvature corrections in Gauss-Bonnet gravity are discussed.

In this paper we construct new wormhole solutions of Lovelock theories in vacuum, when the coupling constants are such that all the maximally symmetric solutions coincide, extending to arbitrary dimensions wormhole solutions previously known in the Chern-Simons case. Like the latter, the wormholes are characterized by an integration constant ${\rho }_0$ that controls the contribution to the energy content from one of the boundaries. Then, we study the effects of the constant ${\rho }_0$ on the spectrum of a massive, (non)minimally coupled scalar probes, with Dirichlet boundary conditions at both asymptotic regions. As a result, a deformed Breitenlohner-Freedman bound emerges, which is sensitive to the value of ${\rho }_0$. The scalar spectra are numerically obtained in detail in dimension five, and in such dimension we also present a new family of wormhole geometries for the Einstein-Gauss-Bonnet theory with a unique vacuum. The new geometries are constructed via a double analytic continuation of a wormhole previously reported in the literature, but now the constant ${\rho }_0$ appears in the centrifugal terms of the equations for the geodesic and scalar probes. The mass of these configurations vanishes nontrivially, since the contributions to the mass integral from each boundary are nonvanishing, but only differ in sign, providing a new example of a spacetime having “mass without mass.”

Utilizing the electric Harrison transformation developed in five-dimensional minimal supergravity, we construct an exact solution characterizing non-BPS (Bogomol’nyi-Prasad-Sommerfield) charged rotating black holes with a horizon cross section of a lens space $L(n;1)$. Among these solutions, only the ones corresponding to $n=0$ and $n=1$ do not have any curvature singularities, conical singularities, Dirac-Misner string singularities, and orbifold singularities both on and outside the horizon; additionally, they are free from closed timelike curves. The solution for $n=0$ corresponds to the charged dipole black ring that we constructed in the previous paper. The specific solution for $n=1$, referred to as the “capped black hole,” was introduced in our previous article. This provides the first example of a non-BPS exact solution, representing an asymptotically flat, stationary spherical black hole with a domain of outer communication (DOC) having a nontrivial topology in five-dimensional minimal supergravity. We demonstrate that the DOC on a time slice has the topology of $[{\mathbb{R}}^4\#\mathbb{C}{\mathbb{P}}^2]\backslash {\mathbb{B}}^4$. Differing from the well-known Myers-Perry and Cvetič-Youm black holes describing a spherical horizon topology and a DOC with a trivial topology of ${\mathbb{R}}^4\backslash {\mathbb{B}}^4$ on a timeslice, the capped black hole’s horizon is capped by a disk-shaped bubble. We explicitly demonstrate that the capped black hole carries mass, two angular momenta, an electric charge, and a magnetic flux, with only three of these quantities being independent. Furthermore, we reveal that this black hole can possess identical conserved charges as the Cvetič-Youm black hole. The existence of this solution challenges black hole uniqueness beyond both the black ring and the BPS spherical black hole. Moreover, within specific parameter regions, the capped black hole can exhibit larger entropy than the Cvetič-Youm black hole.

During its inspiral stage, a binary black hole (BBH) produces characteristic gravitational wave (GW) signals. The waveform of the GW signals can be described by the physical parameters of BBH, such as the masses of the black holes and the orbital eccentricity. Precise and accurate estimation of these parameters is crucial for GW astrophysics. In the aspect of precision, decihertz GW detectors are promising proposals, as they are anticipated to allow us to obtain highly precise parameter estimations for stellar-mass BBHs. However, the high-precision parameter estimation requires accurate GW waveform modeling. Otherwise, systematic errors can arise in estimated parameters. We emphasize the importance of considering the orbital eccentricity in constructing an accurate GW waveform model. B-DECIGO and MAGIS are used as benchmarks for decihertz GW detectors. We examine the significance of systematic error for a population of stellar-mass BBH inspirals. We found that the quasicircular GW waveform model exhibits significant systematic errors for BBH with a very small eccentricity $\sim {10}^{-4}$ at GW frequency 0.1 Hz. The modeling accuracy can be substantially enhanced by incorporating the leading-order correction to GW phase evolution associated with eccentricity smaller than 0.01. The higher-order post-Newtonian corrections induced by eccentricity should be important only for eccentricity larger than 0.01.

We probe the astrophysical gravitational-wave background resulting from compact binary coalescences, focusing on population III binary black holes. We exploit results of state-of-the-art simulations on the evolution of population I-II and III binaries, considering a variety of initial condition and star formation rate models for the latter. The contribution from population III binary black holes is found to be very small, with no effect on the gravitational-wave spectrum. A network of third-generation detectors will detect easier individual population III binaries, due to their significantly higher masses, hence decreasing even further their residual contribution.