Standard lore ritualizes our quantum vacuum in the four-dimensional spacetime (4D) governed by one of the candidate Standard Models (SMs), while lifting towards some grand unification-like structure (GUT) at higher energy scales. In contrast, in our work, we introduce an alternative view that the SM is a low energy quantum vacuum arising from various neighbor vacua competition in an immense quantum phase diagram. In general, we can regard the SM arising near the gapless quantum criticality (either critical points or critical regions) between the competing neighbor vacua. In particular detail, we demonstrate how the $su(3)\times su(2)\times u(1)$ SM with 16n Weyl fermions arises near the quantum criticality between the GUT competition of Georgi-Glashow $su(5)$ and Pati-Salam $su(4)\times su(2)\times su(2)$. We propose two enveloping toy models. Model I is the conventional $so(10)$ GUT with a Spin(10) gauge group plus GUT-Higgs potential inducing various Higgs transitions. Model II modifies model I by adding a new 4D discrete torsion class of Wess-Zumino-Witten-like term built from GUT-Higgs field [which matches a nonperturbative global mixed gauge-gravity anomaly captured by a 5D invertible topological field theory $w_2{w}_3(TM)=w_2{w}_3(V_{\mathrm{SO}(10)})$], which manifests a beyond-Landau-Ginzburg quantum criticality between Georgi-Glashow and Pati-Salam models, with extra beyond the Standard Model excitations emerging near a hypothetical quantum critical region. If the internal symmetries were treated as global symmetries (or weakly coupled to probe background fields), we suggest a particular low-energy realization of model II as an analogous gapless 4D deconfined quantum criticality with new beyond the SM fractionalized fragmentary excitations of color-flavor separation, and gauge enhancement including a dark gauge force sector, altogether requiring a double fermionic Spin structure named DSpin. If the internal symmetries are dynamically gauged (as they are in our quantum vacuum), we suggest the model II’s 4D criticality as a boundary criticality such that only appropriately gauge enhanced dynamical GUT gauge fields can propagate into an extradimensional 5D bulk. The phenomena may be regarded as SM deformation or “morphogenesis.” Although our derivation is based on kinematics and global anomaly matching constraints between UV parent and various candidate IR field theories, the constraints are still highly subtle and suggestive. Future verifications on the IR dynamics will be desirable.

A simple but powerful particle detector model consists of a two-level system coupled to a field, where the detected particles are the field excitations. This is known as the Unruh-DeWitt detector. Research using this model has often focused on either a completely classical description of the external degrees of freedom of the detector, or a full field-theoretic treatment, where the detector itself is described as a field. Recently there has been much interest in quantum aspects of the detector’s center of mass—either described as moving in superposition along semiclassical trajectories, or dynamically evolving under a nonrelativistic Hamiltonian. However, the processes of interest—the absorption or emission of field particles—necessarily change the detector’s rest mass by the amount of energy of the absorbed or emitted field quanta. Neither of the above models can capture such effects. Here we incorporate the quantization of the detector’s mass-energy into the Unruh-DeWitt model. We show that internal energy changes due to emission or absorption are relevant even in the lowest energy limit. Specifically, corrections to transition rates due to the detector’s mass changing cannot be ignored unless the entire center of mass dynamics is also ignored. Our results imply that one cannot have a consistent model of the Unruh-DeWitt detector as a massive particle without including the mass-energy equivalence.

We analyze the Lagrangian and Hamiltonian formulations of the Maxwell-Chern-Simons theory defined on a manifold with boundary for two different sets of boundary equations derived from a variational principle. We pay special attention to the identification of the infinite chains of boundary constraints and their resolution. We identify edge observables and their algebra [which corresponds to the well-known $U(1)$ Kac-Moody algebra]. Without performing any gauge fixing, and using the Hodge-Morrey theorem, we solve the Hamilton equations whenever possible. In order to give explicit solutions, we consider the particular case in which the fields are defined on a 2-disk. Finally, we study the Fock quantization of the system and discuss the quantum edge observables and states.

We present a new family of exact four-dimensional Taub-NUT spacetimes in Einstein-$\mathrm{\Lambda }$ theory supplemented with a conformally coupled scalar field exhibiting a power-counting superrenormalizable potential. Our configurations are constructed in the following manner: A solution of a conformally coupled theory with a conformal potential, henceforth the seed $(g_{\mu \nu },\varphi )$, is transformed by the action of a specific change of frame in addition with a simultaneous shift of the seed scalar field. The conformal factor of the transformation and the shift are both affine functions of the original scalar $\varphi$. The new configuration, $({\overline{g}}_{\mu \nu },\overline{\varphi })$, solves the field equations of a conformally coupled theory with the extended aforementioned superrenormalizable potential, this under the presence of an effective cosmological constant. The new spectrum of solutions is notoriously enhanced with respect to the original seed containing regular black holes, wormholes, and bouncing cosmologies. We highlight the existence of two types of exact black bounces given by de Sitter and anti–de Sitter geometries that transit across three different configurations each. The de Sitter geometries transit from a regular black hole with event and cosmological horizons to a bouncing cosmology that connects two de Sitter Universes with different values of the asymptotic cosmological constant. An intermediate phase, which might be represented by two different configurations, takes place. These configurations are given by a de Sitter wormhole or by a bouncing cosmology that connects two de Sitter Universes, both under the presence of a cosmological horizon. On the other hand, the anti–de Sitter geometries transit from a regular black hole with inner and event horizons to a wormhole that connects two asymptotic boundaries with different constant curvatures. The intermediate phase is given in this case by an anti–de Sitter regular black hole with a single event horizon. This regular black hole might appear in two different configurations. As a regular anti–de Sitter black hole inside of an anti-de Sitter wormhole or as an anti–de Sitter regular black hole with a cosmological bounce in its interior. All these geometries are shown to be smoothly connected by the mass parameter only. Other standard stationary black holes, bouncing cosmologies and wormholes are also identified.

We consider the decay of a particle with some energy $E_0>0$ inside the ergosphere of a black hole. After the first decay, one of particles with the energy $E_1<0$ falls towards a black hole while the second one with $E_2>E_0$ moves in the outward direction. It bounces back from a reflecting shell and, afterwards, the process repeats. For radial motion of charged particles in the Reissner-Nordstöm metric, the result depends strongly on a concrete scenario. In particular, an indefinitely large growth of energy inside a shell is possible that gives rise to a black-hole bomb. We also consider a similar multiple process with neutral particles in the background of a rotating axially symmetric stationary black hole. We demonstrate that, if particle decay occurs in the turning point, a black-hole bomb in this case is impossible at all. For a generic point inside the ergoregion, there is a condition for a black-hole bomb to exist. It relates the to ratio of masses before and after decay and the velocity of a fragment in the center of mass frame.

As a first application of the new adaptive mesh functionality of the pseudospectral numerical relativity code bamps, we evolve twist-free, axisymmetric gravitational waves close to the threshold of collapse. We consider six different one-parameter families of Brill wave initial data; two centered and four off-centered families. Of these the latter have not been treated before. Within each family, we tune the parameter towards the threshold of black hole formation. The results for centered data agree with earlier work. Our key results are first, that close to the threshold of collapse the global peak in the curvature appears on the symmetry axis but away from the origin, indicating that in the limit they will collapse around disjoint centers. This is confirmed in three of the six families by explicitly finding apparent horizons around these large curvature peaks. Second, we find evidence neither for strict discrete-self-similarity nor for universal power-law scaling of curvature quantities. Finally, as in Ledvinka and Khirnov’s recent study, we find approximately universal strong curvature features. These features appear multiple times within individual spacetimes close to the threshold and are furthermore present within all six families.

Current observations allow primordial black holes (PBHs) in asteroid mass range ${10}^{17}–{10}^{22}\mathrm{g}$ to constitute the entire dark matter energy density (barring a small mass range constrained by 21-cm observations). In this work, we explore the possibility of probing PBHs with masses ${10}^{17}–{10}^{19}\mathrm{g}$ via the upcoming X/Gamma Ray Imaging Spectrometer (XGIS) telescope array on board the Transient High-Energy Sky and Early Universe Surveyor (THESEUS) mission. While our projected limits are comparable with those proposed in the literature for ${10}^{16}\mathrm{g}<M_{\mathrm{PBH}}<{10}^{17}\mathrm{g}$, we show that the XGIS-THESEUS mission can potentially provide the strongest bound for ${10}^{17}\mathrm{g}<M_{\mathrm{PBH}}\lesssim 3\times {10}^{18}\mathrm{g}$ for nonrotating PBHs. The bounds become more stringent by nearly an order of magnitude for maximally rotating PBHs in the mass range $5\times {10}^{15}\mathrm{g}<M_{\mathrm{PBH}}\lesssim {10}^{19}\mathrm{g}$.

The ultrahigh energy range of neutrino physics (above $\sim {10}^7\mathrm{GeV}$), as yet devoid of detections, is an open landscape with challenges to be met and discoveries to be made. Neutrino-nucleon cross sections in that range—with center-of-momentum energies $\sqrt{s}\gtrsim 4\mathrm{TeV}$—are powerful probes of unexplored phenomena. We present a simple and accurate model-independent framework to evaluate how well these cross sections can be measured for an unknown flux and generic detectors. We also demonstrate how to characterize and compare detector sensitivity. We show that cross sections can be measured to ${\simeq }_{-30}^{+65}\%$ precision over $\sqrt{s}\simeq 4–140\mathrm{TeV}$ ($E_{\nu }={10}^7-{10}^{10}\mathrm{GeV}$) with modest energy and angular resolution and $\simeq 10$ events per energy decade. Many allowed novel-physics models (extra dimensions, leptoquarks, etc.) produce much larger effects. In the distant future, with $\simeq 100$ events at the highest energies, the precision would be $\simeq 15\%$, probing even QCD saturation effects.

The primary scientific results of the future space-based gravitational wave interferometer LISA will come from the parameter inference of a large variety of gravitational wave sources. However, the presence of calibration errors could potentially degrade the measurement precision of the system parameters. Here, we assess the impact of calibration uncertainties on parameter estimation for individual sources, focusing on massive black holes, extreme-mass-ratio inspirals (EMRIs), galactic binaries, and stellar origin black hole binaries. Using a Fisher matrix formalism, we investigate how the measurement precision of source parameters degrades as a function of the size of the assumed calibration uncertainties. If we require that parameter measurements are degraded by no more than a factor of two relative to their value in the absence of calibration error, we find that calibration errors should be smaller than a few tenths of a percent in amplitude and ${10}^{-3}$ in phase. We also investigate the possibility of using verification binaries and EMRIs to constrain calibration uncertainties. Verification binaries can constrain amplitude calibration uncertainties at the level of a few percent, while both source types can constrain phase calibration at the level of a $\mathrm{few}\times {10}^{-2}$.

Quantum vacuum friction experienced by an atom, where the only dissipative mechanism is through its interaction with the radiation field, has been studied in our recent paper [Phys. Rev. D 104, 116006 (2021)]. Quantum vacuum friction on an intrinsically dissipative particle is different in that the friction arises not only from the field fluctuations but also from the dipole fluctuations intrinsic to the particle. As a result, the dissipative particle can be out of the nonequilibrium steady state (NESS), and therefore loses or gains internal energy (rest mass). Only if the temperature of the particle equals a special NESS temperature will the particle be in NESS. In this paper, general NESS conditions are derived which give the NESS temperature of the particle as a function of the temperature of the radiation and the velocity of the particle. Imposing the NESS conditions, we also obtain an expression for the quantum vacuum friction in NESS. The NESS quantum vacuum friction is shown to be negative definite (opposing the motion of the particle) and equivalent to that found in our previous paper if the dissipation mechanism is restricted to radiation reaction. The NESS temperature and quantum vacuum friction are calculated numerically for various models. In particular, we show that, for a gold nanosphere, the deviation of its NESS temperature from the temperature of the radiation can be substantial and it is also possible to detect the NESS quantum vacuum friction directly at sufficiently high temperatures. Out of NESS, even though the quantum vacuum friction no longer has a definite sign in the rest frame of the radiation, the friction in the rest frame of the particle is still negative definite. Also, the external force needed to keep the particle moving must be in the same direction as the motion of the particle, therefore excluding the possibility of a perpetual motion machine, which could convert the vacuum energy into useful mechanical work. In addition, we find that the deviation of the temperature of the particle from its NESS temperature causes the particle to lose or gain internal energy in such a way that the particle would return to NESS after deviating from it. This enables experimental measurements of the NESS temperature of the particle to serve as a feasible signature for these quantum vacuum frictional effects.

Using the Coulomb gauge formulation of QED, we present a lattice QCD procedure to calculate the ${\pi }^{+}{\pi }^{+}$ scattering phase shift including the effects of the Coulomb potential, which appears in this formulation. The approach described here incorporates the effects of relativity and avoids finite-volume corrections that vanish as a power of the volume in which the lattice calculation is performed. This is the first step in developing a complete lattice QCD calculation of the electromagnetic and isospin-breaking light-quark mass contributions to ${ϵ}^{\prime }$, the parameter describing direct $CP$ violating effects in $K_L\to \pi \pi$ decay.

Large-momentum effective theory allows extraction of hadron parton distribution functions in lattice QCD by matching them to quark bilinear matrix elements of hadrons with large momenta. We calculate the matching kernels for the unpolarized, helicity, and transversity-isovector parton distribution functions and skewless generalized parton distributions of all hadrons in the hybrid-regularization-invariant momentum subtraction (RI/MOM) scheme. This renormalization scheme uses RI/MOM when the Wilson line length is less than $z_s$, otherwise a mass subtraction scheme is used. By design, the nonhybrid scheme is recovered as $z_s\to \infty$. In the opposite limit, $z_s\to 0$, the self-renormalization scheme is obtained. When the parameters $p_z^R=0$ and ${\mu }^R{z}_s\ll 1$, the hybrid-RI/MOM scheme coincides with the hybrid-ratio scheme times the charge of the PDF. We also discuss the subtlety related to the commutativity of Fourier transform and $\epsilon$ expansion in the $\overline{\mathrm{MS}}$ scheme.

We report the measured production rates of unstable isotopes ${}^9\mathrm{Li}$ and ${}^8\mathrm{He}$ produced by cosmic muon spallation on ${}^{12}\mathrm{C}$ using two identical detectors of the RENO experiment. Their $\beta$ decays accompanied by a neutron make a significant contribution to backgrounds of reactor antineutrino events in precise determination of the smallest neutrino mixing angle. The mean muon energy of its near (far) detector with an overburden of 120 (450) m.w.e. is estimated as $33.1\pm 2.3(73.6\pm 4.4)\mathrm{GeV}$. Based on roughly 3100 days of data, the cosmogenic production rate of ${}^9\mathrm{Li}({}^8\mathrm{He})$ isotope is measured to be $44.2\pm 3.1(10.6\pm 7.4)$ per day at near detector and $10.0\pm 1.1(2.1\pm 1.5)$ per day at far detector. This corresponds to yields of ${}^9\mathrm{Li}({}^8\mathrm{He})$, $4.80\pm 0.36(1.15\pm 0.81)$ and $9.9\pm 1.1(2.1\pm 1.5)$ at near and far detectors, respectively, in a unit of ${10}^{-8}{\mu }^{-1}{\mathrm{g}}^{-1}{\mathrm{cm}}^2$. Combining the measured ${}^9\mathrm{Li}$ yields with other available underground measurements, an excellent power-law relationship of the yield with respect to the mean muon energy is found to have an exponent of $\alpha =0.75\pm 0.05$.

We investigate the correlation harvesting protocol for mutual information between two Unruh-DeWitt detectors in a static Bañados-Teitelboim-Zanelli black hole spacetime. Here, the effects coming from communication and change in proper separation of the detectors are set to be negligible so that only a black hole affects the extracted mutual information. We find that, unlike the entanglement harvesting scenario, harvested mutual information is zero only when a detector reaches an event horizon, and that although the Hawking effect and gravitational redshift both affect the extraction of mutual information, it is extreme Hawking radiation that inhibits the detectors from harvesting.

In this article, we conduct a sequential study of possible observable images of black hole simulators described by two recently obtained rotating geometries in Einstein gravity, minimally coupled to a scalar field. One of them, “Kerr-like,” can be seen as a legitimate alternative to the rotating Fisher-Janis-Newman-Winicour solution, and the other (TSL) is a scalar generalization of the Tomimatsu-Sato-like solution. Unlike the previous version of the rotating Fisher-Janis-Newman-Winicour solution, these solutions do indeed satisfy the system’s equations of motion. Our study includes both analytical and numerical calculations of equatorial circular orbits, photon regions, gravitational shadows, and radiation from thin accretion disks for various values of the object’s angular momentum and scalar charge. The TSL solution was found to simulate Kerr for all valid parameter values with high accuracy. The maximum difference between the deviations of shadows from a circle for the Kerr and TSL cases does not exceed 1% and fits into the experimental observational data ${\mathrm{M}87}^{*}$ and $\mathrm{Sgr}{\mathrm{A}}^{*}$. However, near-extreme objects show two times smaller peak values of the observed outflow luminosity of the accretion disk than for the Kerr black hole. The Kerr-like solution cannot be ruled out by the experimental data for small values of the scalar charge either. As the scalar charge increases, the optical properties change dramatically. The shadow can become multiply connected, strongly oblate, and the photon region does not hide the singularity, so it should be classified as a strong singularity.

We propose a braneworld scenario in a modified symmetric teleparallel gravitational theory, where the dynamics for the gravitational field is encoded in the nonmetricity tensor rather than in the curvature. Assuming a single real scalar field with a sine-Gordon self-interaction, the generalized quadratic nonmetricity invariant $\mathbb{Q}$ controls the brane width while keeping the shape of the energy density. By considering power corrections of the invariant $\mathbb{Q}$ in the gravitational Lagrangian, the sine-Gordon potential is modified exhibiting new barriers and false vacuum. As a result, the domain wall brane obtains an inner structure, and it undergoes a splitting process. In addition, we also propose a nonminimal coupling between a bulk fermion field and the nonmetricity invariant $\mathbb{Q}$. Such geometric coupling leads to a massless chiral fermion bound to the 3-brane and a stable tower of nonlocalized massive states.

In our previous work, we investigated the effect of the hypothetical reflecting boundary near the black hole event horizon on the waveform from extreme mass-ratio inspirals (EMRIs). Even if the reflection efficiency is not extremely high, we found that a significant modification of the waveform can be expected. Then, the question is how to implement the search for this signature in the actual data analysis of future space gravitational wave antennas, such as LISA. In this paper, we propose a simple but efficient method to detect the signature of the reflecting boundary. The interesting feature of the effect of the reflecting boundary on the orbital evolution of EMRIs is that the energy and angular momentum loss rates periodically oscillate in the frequency domain. The oscillation period is corresponding to the inverse timescale for the round trip of gravitational waves between the hypothetical boundary and the angular momentum barrier. We will show that this peculiar feature allows us to detect the signature of the reflecting boundary without much additional computational cost.

As previously proposed in Simpson and Visser [J. Cosmol. Astropart. Phys. 02 (2019) 042], Mazza et al. [J. Cosmol. Astropart. Phys. 04 (2021) 082], Franzin et al. [J. Cosmol. Astropart. Phys. 07 (2021) 036], and Lobo et al. [Phys. Rev. D 103, 084052 (2021), the “black bounce” spacetimes are an interesting type of globally regular modifications of the ordinary black holes (such as the Kerr-Newman geometry and its particular cases) which generically contain a spacetime singularity (usually of the curvature type) at their center. To transforms a static, spherically symmetric and asymptotically flat black hole (SSS-AF-BH) geometry regular everywhere except its center of symmetry $r=0$ (where $r$ stands for the “areal radius” of the two-dimensional spheres of symmetry) and with (outer) event horizon at $r=r_h>0$, into a black bounce spacetime, is to simply replace $r$ with $\sqrt{{\rho }^2+a^2}$ and $dr$ with $d\rho$, being $\rho$ a new radial coordinate, and $a$ is some real constant nonzero. As long as $r_h=\sqrt{{\rho }_h^2+a^2}>|a|$, the result is a globally regular (or singularity-free) black hole spacetime (called black bounce) where the singularity that occurs in the ordinary SSS-AF-BH geometry at $r=0$ now in the transformed geometry turns into a regular spacetime region determined by the two-dimensional spheres of symmetry of radius $|a|$, while the areal radius $\sqrt{{\rho }^2+a^2}$ always remains positive for all $\rho \in (-\infty ,\infty )$ and has a minimum at $\rho =0$ given by $|a|$. Hence, in the transformed spacetime, the areal radius has a minimum, decreasing before and increasing after this minimum (defining two SSS-AF regions that bounce). In this work we will present several black-bounces exact solutions of General Relativity. Among them is a novel type of black-bounce solution, which in contrast to the Simpson-Visser type {[Simpson and Visser, J. Cosmol. Astropart. Phys. 02 (2019) 042], [Mazza et al., J. Cosmol. Astropart. Phys. 04 (2021) 082], [Franzin et al., J. Cosmol. Astropart. Phys. 07 (2021) 036], [Lobo et al., Phys. Rev. D 103, 084052 (2021)]}, does not have the Ellis wormhole metric as a particular case. The source of these solutions is linear superposition of phantom scalar fields and nonlinear electromagnetic fields.

Ultralight bosons are promising dark matter candidates and can trigger superradiant instabilities of spinning black holes (BHs), resulting in long-lived rotating “bosonic clouds” around the BHs and dissipating their energy through the emission of monochromatic gravitational waves (GWs). We focus on the scalar bosons minimally coupled with both isolated stellar-origin BHs (SBH) and their binary merger remnants, and perform Bayesian data analysis to search for the stochastic GW background from all the unstable modes that can trigger the superradiant instabilities using the data of Advanced LIGO and Advanced Virgo’s first three observing runs. We find no evidence for such signal, and hence rule out the scalar bosons within the mass range $[1.5,15]\times {10}^{-13}\mathrm{eV}$, $[1.8,8.1]\times {10}^{-13}\mathrm{eV}$, and $[1.3,17]\times {10}^{-13}\mathrm{eV}$ at 95% confidence level for isolated SBHs having a uniform dimensionless spin distribution in [0, 1], [0, 0.5], and [0.5, 1], respectively.

The data collected by the current network of gravitational-wave detectors are largely dominated by instrumental noise. Total variation methods based on $L_1$-norm minimization have recently been proposed as a powerful technique for noise removal in gravitational-wave data. In particular, the regularized Rudin-Osher-Fatemi (rROF) model has proven effective to denoise signals embedded in either simulated Gaussian noise or actual detector noise. Importing the rROF model to existing search pipelines seems therefore worth considering. In this paper, we discuss the implementation of two variants of the rROF algorithm as two separate plug-ins of the coherent WaveBurst (cWB) pipeline designed to conduct searches of unmodelled gravitational-wave burst sources. The first approach is based on a single-step rROF method and the second one employs an iterative rROF procedure. Both approaches are calibrated using actual gravitational-wave events from the first three observing runs of the LIGO-Virgo-KAGRA collaboration, namely GW1501914, GW151226, GW170817, and GW190521, encompassing different types of compact binary coalescences. Our analysis shows that the iterative version of the rROF denoising algorithm implemented in the cWB pipeline effectively eliminates noise while preserving the waveform signals intact. Therefore, the combined approach yields higher signal-to-noise values than those computed by the cWB pipeline without the rROF denoising step. The incorporation of the iterative rROF algorithm in the cWB pipeline might hence impact the detectability capabilities of the pipeline along with the inference of source properties.