Loop quantization of Schwarzschild black holes with a cosmological constant for polymerization parameters which are constant is studied in the effective spacetime description. We show that for the positive cosmological constant there can be an appearance of large quantum effects at small spacetime curvatures. These effects can manifest as an additional black hole horizon. While the central singularity is resolved in all the cases, these limitations demonstrate incompatibility of the Kantowski-Sachs gauge and schemes with fixed polymerization parameters in the presence of a positive cosmological constant. In contrast, the case of a negative cosmological constant is free of such problematic features. Noted limitations are similar to those in the ${\mu }_o$ scheme for the loop quantization of cosmological models.

This paper proposes several criteria to probe the nontrivialities of four-dimensional geometry that impact spinfoam amplitude. These criteria include the standard deviation of 4-volumes of the constituting 4-simplices, the smallest 4-simplex volume, and whether the directions of tetrahedron 4-normals are close to the null direction. By numerically computing and analyzing the spinfoam amplitudes up to the next-to-leading order of 1-5 Pachner move samples with the same boundary 4-simplex, we reveal the relationship between four-dimensional geometry and spinfoam amplitudes, as large standard deviation of 4-simplex volumes and small 4-simplex volume can result in both leading order and next-to-leading order amplitudes being large. Furthermore, the numerical result indicates that the distance from tetrahedron 4-normals to the null direction has a greater impact on increasing the next-to-leading order amplitude than on the leading order amplitude, making it primarily a quantum effect.

This paper describes the different steps to include the adiabatic tidal effects to the gravitational waveform amplitude for quasicircular nonspinning compact binaries up to the second-and-a-half post-Newtonian (PN) order. The amplitude, that relates the two gravitational wave polarizations, is decomposed onto the basis of spin-weighted spherical harmonics of spin $-2$, parametrized by the two numbers $(\ell ,m)$, where the modes of the waveform correspond to the coefficients of the decomposition. These modes are readily computed from the radiative multipole moments. They can be expressed in a PN-expanded form as well as in a factorized form, suitable to be directly included in effective-one-body models to describe more accurately the waveform of binary neutron stars. We also provide the energy flux and phasing evolution in time and frequency domain.

We elaborate on the problem of a magnetized particle motion in the spacetime of a static, spherically symmetric black hole influenced by weak magnetic fields stemming from visible and dark matter sectors. The Wald’s procedure for obtaining the weakly magnetized solution, was generalized to the case of dark photon—Einstein-Maxwell gravity was implemented. The collision process analysis of two particles in the background of the black hole has been studied in order to find the signature of the presence of dark matter nearby to the object in question.

Using high-accuracy numerical relativity waveforms, we confirm the presence of numerous overtones of the $\ell =2$, $m=2$ quasinormal mode early in the ringdown of binary black hole mergers. We do this by demonstrating the stability of the mode amplitudes at different fit times, ruling out the possibility that a linear superposition of modes unphysically fits a highly nonlinear part of the waveform. We also find a number of previously unidentified subdominant second-order quasinormal modes in the (2, 2) mode. Even though these modes are mathematically nonlinear, they nevertheless confirm the validity of perturbation theory as a good approximation for describing much of the ringdown.

From CMB polarization data alone, we reconstruct the CMB lensing power spectrum, comparable in overall constraining power to previous temperature-based reconstructions, and an unlensed $E$-mode power spectrum, with clear detections of the third through the tenth acoustic peaks. The observations, taken in 2019 and 2020 with the South Pole Telescope (SPT) and the SPT-3G camera, cover $1500{\mathrm{deg}}^2$ at 95, 150, and 220 GHz with arcminute resolution and roughly $4.9\mathrm{\mu }\mathrm{K}\text{−}\mathrm{arcmin}$ coadded noise in polarization. The power spectrum estimates, together with systematic parameter estimates and a joint covariance matrix, follow from a Bayesian analysis using the marginal unbiased score expansion (MUSE) method. The $E$-mode spectrum at $\ell >2000$ and lensing spectrum at $L>350$ are the most precise to date. Assuming the $\mathrm{\Lambda }\mathrm{CDM}$ model, and using only these SPT data and priors on $\tau$ and absolute calibration from Planck, we find $H_0=66.81\pm 0.81\mathrm{km}/\mathrm{s}/\mathrm{Mpc}$, comparable in precision to the Planck determination and in $5.4\sigma$ tension with the most precise $H_0$ inference derived via the distance ladder. We also find $S_8\equiv {\sigma }_8({\mathrm{\Omega }}_{\mathrm{m}}/0.3{)}^{0.5}=0.850\pm 0.017$, providing further independent evidence of a slight tension with low-redshift structure probes. The $\mathrm{\Lambda }\mathrm{CDM}$ model provides a good simultaneous fit to the combined Planck, ACT, and SPT data, and thus passes a powerful test. Combining these CMB datasets with BAO observations, we explore extensions to the $\mathrm{\Lambda }\mathrm{CDM}$ model. We find that the effective number of neutrino species, spatial curvature, and primordial helium fraction are consistent with standard model values, and that the 95% confidence upper limit on the neutrino mass sum is 0.075 eV, close to the minimum sum expected from observations of solar and atmospheric neutrino oscillations. The SPT data are consistent with the somewhat weak ($<3\sigma$) preference for excess lensing power seen in Planck and ACT data relative to predictions of the $\mathrm{\Lambda }\mathrm{CDM}$ model given the combined Planck, ACT, and BAO datasets. We also detect at greater than $3\sigma$ the influence of nonlinear evolution in the CMB lensing power spectrum and discuss it in the context of the $S_8$ tension. Forthcoming SPT-3G analyses will feature deeper and wider observations in temperature and polarization, providing even tighter constraints and more powerful tests of the $\mathrm{\Lambda }\mathrm{CDM}$ model.

The dynamics of a black hole traveling through a plasma—a general relativistic extension of the classic Bondi-Hoyle-Lyttleton (BHL) accretion problem—can be related to a variety of astrophysical contexts, including the aftermath of binary black hole mergers in gaseous environments. We perform three-dimensional general relativistic magnetohydrodynamics simulations of BHL accretion onto a spinning black hole when magnetic field of the incoming wind is inclined to the spin axis of the black hole. Irrespective of inclination but dependent on the wind speed, we find that the accretion flow onto the black hole can become magnetically arrested, launching an intermittent jet whose formation is assisted by a turbulent dynamolike process in the inner disk. The upstream ram pressure of the wind bends the jet, and confines the angular extent into which the magnetic flux tubes ejected from quasiperiodic eruptions are released. Recoil from magnetic flux eruptions drives strong oscillations in the inner accretion disk, resulting in jet nutation at the outer radii and occasionally ripping off the inner part of the accretion disk. When the incoming magnetic field is perpendicular to the spin axis of the black hole, we find that the magnetic polarity of the jets can undergo a stochastic reversal. In addition to dynamical friction, the black hole experiences a perpendicular drag force analogous to the Magnus effect. Qualitative effects of the incoming magnetic field orientation, the strength of the magnetization, and the incoming wind speed are investigated as well.

The oscillation spectrum of a neutron star is notably rich and intrinsically dependent on the equation of state of nuclear matter. With recent advancements in gravitational-wave and electromagnetic astronomy, we are nearing the capability to perform neutron-star asteroseismology and probe the complex physics of neutron stars. With this in mind, we explore the implementation of three-parameter finite-temperature matter models in the computation of neutron-star oscillations. We consider in detail the thermodynamics of nuclear matter and show how this information enters the problem. Our realistic treatment takes into account entropy and composition gradients that exist in the nuclear matter, giving rise to buoyant $g$-mode oscillations. To illustrate the implementation, we determine the oscillation spectrum of a low-temperature neutron star. In addition to the expected compositional and thermal $g$-modes, we find perturbations sourced by phase transitions in the equation of state. We also examine two thermal models, comparing the results for constant redshifted temperature with those for uniform entropy per baryon.

The Schrödinger-Newton equation, a theoretical framework connecting quantum mechanics with classical gravity, predicts that gravity may induce measurable deviations in low-frequency mechanical systems—an intriguing hypothesis at the frontier of fundamental physics. In this study, we developed and operated an advanced optomechanical platform to investigate these effects. The system integrates an optical cavity with finesse over $3.5\times {10}^5$ and a torsion pendulum with an ultralow eigenfrequency of 0.6 mHz, achieving a high mechanical quality factor exceeding $5\times {10}^4$. We collected data for three months and reached a sensitivity of $0.3\mathrm{\mu }\mathrm{rad}/\sqrt{\mathrm{Hz}}$ at the Schrödinger-Newton frequency of 2.5 mHz where deviations from the standard quantum mechanics may occur. While no evidence supporting semiclassical gravity was found, we identify key challenges in such tests and propose new experimental approaches to advance this line of inquiry. This work demonstrates the potential of precision optomechanics to probe the interplay between quantum mechanics and gravity.

We present an event-by-event study of photons produced by the chiral magnetic effect in the early stage of high-energy nuclear collisions. We model the early stage with an evolving, $2+1$ dimensional, glasma, initialized via the McLerran-Venugopalan model. The photons are produced from the interplay of the chiral anomaly of quantum chromodynamics and the strong magnetic fields generated by the colliding nuclei. In particular, we focus on the spectrum and the elliptic flow of the produced photons. We find that the chiral magnetic effect has a minor impact on the photon spectrum compared to other production mechanisms as well as to experimental data. However, the photons produced by the present early stage mechanism can exhibit a significant elliptic flow.

We analyze the properties of Krylov state complexity in qubit dynamics, considering a single qubit and a qubit pair. A geometrical picture of the Krylov complexity is discussed for the single-qubit case, whereas it becomes non-trivial for the two-qubit case. Considering the particular case of interacting Rydberg two-level atoms, we show that the Krylov basis obtained using an effective Hamiltonian minimizes the time-averaged spread complexity compared to that which is obtained from the original Hamiltonian. We further generalize the latter property to an arbitrary Hamiltonian in which the entire Hilbert space comprises of two subspaces provided a weak coupling between them.

In the paper, we conduct a detailed investigation of the rare decay processes of charged meson, specifically $B^{+}\to K^{+}{\ell }^{+}{\ell }^{-}$ with $\ell =(e,\mu ,\tau )$ and $B^{+}\to K^{+}\nu \overline{\nu }$. These processes involve flavor-changing-neutral-current (FCNC) transitions, namely $b\to s{\ell }^{+}{\ell }^{-}$ and $b\to s\nu \overline{\nu }$. The essential components $B\to K$ scalar, vector, and tensor transition form factors (TFFs) are calculated by using the QCD light-cone sum rules approach up to next-to-leading order QCD corrections. In which, the kaon twist-2 and twist-3 light-cone distribution amplitudes are calculated from both the QCD sum rules within the framework of background field theory and the light-cone harmonic oscillator model. The TFFs at large recoil point are $f_{+}^{BK}(0)=f_0^{BK}(0)=0.344_{-0.018}^{+0.021}$ and $f_{\mathrm{T}}^{BK}(0)=0.349_{-0.019}^{+0.021}$, respectively. To obtain the behavior of those TFFs in the whole $q^2$ region, we extrapolate them by utilizing the simplified $z(q^2)$-series expansion. Furthermore, we compute the differential branching fractions with respect to the squared dilepton invariant mass for the two different decay channels and present the corresponding curves. Our predictions of total branching fraction are $\mathcal{B}(B^{+}\to K^{+}{e}^{+}{e}^{-})=6.623_{-0.709}^{+0.648}\times {10}^{-7}$, $\mathcal{B}(B^{+}\to K^{+}{\mu }^{+}{\mu }^{-})=6.612_{-0.698}^{+0.638}\times {10}^{-7}$, $\mathcal{B}(B^{+}\to K^{+}{\tau }^{+}{\tau }^{-})=1.795_{-0.116}^{+0.110}\times {10}^{-7}$, and $\mathcal{B}(B^{+}\to K^{+}\nu \overline{\nu })=4.170_{-0.440}^{+0.402}\times {10}^{-6}$, respectively. Lastly, the observables such as the lepton universality ${\mathcal{R}}_K$ and the angular distribution “flat term” $F_{\mathrm{H}}^{\ell }$ are given, which show good agreement with the theoretical and experimental predictions.

We propose using highly excited cyclotron states of a trapped electron to detect meV axion and dark-photon dark matter, marking a significant improvement over our previous proposal and demonstration [One-electron quantum cyclotron as a milli-ev dark-photon detector, Phys. Rev. Lett. 129, 261801 (2022).]. When the axion mass matches the cyclotron frequency ${\omega }_c$, the cyclotron state is resonantly excited, with a transition probability proportional to its initial quantum number, $n_c$. The sensitivity is enhanced by taking $n_c\sim {10}^6{(\frac{0.1\mathrm{meV}}{{\omega }_c})}^2$. By optimizing key experimental parameters, we minimize the required averaging time for cyclotron detection to $t_{\mathrm{ave}}\sim {10}^{-6}$ s, permitting detection of such a highly excited state before its decay. An open–end-cap trap design enables the external photon signal to be directed into the trap, rendering our background-free detector compatible with large focusing cavities, such as the BREAD proposal, while capitalizing on their strong magnetic fields. Furthermore, the axion conversion rate can be coherently enhanced by incorporating layers of dielectrics with alternating refractive indices within the cavity. Collectively, these optimizations enable us to probe the QCD axion parameter space from 0.1 to 2.3 meV (25–560 GHz), covering a substantial portion of the predicted postinflationary QCD axion mass range. This sensitivity corresponds to probing the kinetic mixing parameter of the dark photon down to $\epsilon \approx 2\times {10}^{-16}$.

We study the deconfinement transition in ($2+1$)-dimensional lattice ${\mathbb{Z}}_2$ gauge theory both as a percolation transition of center vortices and as a localization transition for the low-lying Dirac modes. We study in detail the critical properties of the Anderson transition in the Dirac spectrum in the deconfined phase, showing that it is of BKT type; and the critical properties of the center-vortex percolation transition, showing that they differ from those of ordinary two-dimensional percolation. We then study the relation between localized modes and center vortices in the deconfined phase, identifying the simple center-vortex structures that mainly support the localized Dirac modes. As the system transitions to the confined phase, center vortices merge together into an infinite cluster, causing the low Dirac modes to delocalize.

We outline a general framework for evaluating the nonperturbative soft functions in the quantum chromodynamics (QCD) instanton vacuum. In particular, from the soft function we derive the Collins-Soper (CS) kernel, which drives the rapidity evolution of the transverse-momentum-dependent parton distributions. The resulting CS kernel, when supplemented with the perturbative contribution, agrees well with recent lattice results and some phenomenological parametrizations. Moreover, our CS kernel depends logarithmically on the large quark transverse separation, providing a key constraint on its phenomenological parametrization. Finally, a lattice calculation can be directly compared to our generic results in Euclidean signature, thus providing a new approach for evalulating the soft function and extracting the CS kernel by analytical continuation.

I consider ${\mathrm{QCD}}_2$ in the $N_c\to \infty$ limit at fixed $g^2{N}_c$. The derivation starts from equal-time $q\overline{q}$ bound states in coordinate space and temporal ($A^0=0$) gauge, avoiding the use of quark and gluon propagators. The wave function is given analytically by a ${}_1{F}_1$ function with an explicit frame dependence. In the infinite momentum frame the Fourier transformed wave function satisfies the ’t Hooft equation, however with contributions also from quarks with negative kinetic energy. Such contributions are present also in the rest frame, and do not vanish under boosts.

The violation of the Lam-Tung relation in the high-$p_T^{\ell \ell }$ region of the Drell-Yan process at the LHC presents a longstanding discrepancy with the standard model prediction at $\mathcal{O}({\alpha }_s^3)$ accuracy. In this paper, we employed a model-independent analysis to investigate this phenomenon within the framework of the standard model effective field theory (SMEFT). Our findings revealed that the leading contributions from SMEFT to this violation appear at the $1/{\mathrm{\Lambda }}^4$ order with $\mathcal{O}({\alpha }_s)$ accuracy in quantum chromodynamics (QCD) interaction. Notably, we demonstrated that the quadratic effect of dimension-6 dipole operators, associated with the $Z$ boson, dominates the breaking effects induced by various dimension-6 and dimension-8 operators. This provides a possible explanation for the observed discrepancy with the Standard Model predictions at the LHC. Furthermore, the breaking effects could also serve as a powerful tool for constraining $Z$-boson dipole interactions, highlighting their importance among potential sources of new physics in the Drell-Yan process.

Coherent elastic neutrino-nucleus ($\mathrm{CE}\nu \mathrm{NS}$) and elastic neutrino-electron scattering ($\mathrm{E}\nu \mathrm{ES}$) data are exploited to constrain “chiral” $U(1{)}_X$ gauged models with light vector mediator mass. These models fall under a distinct class of new symmetries called dark hypercharge symmetries. A key feature is the fact that the $Z^{\prime }$ boson can couple to all Standard Model fermions at tree level, with the $U(1{)}_X$ charges determined by the requirement of anomaly cancellation. Notably, the charges of leptons and quarks can differ significantly depending on the specific anomaly cancellation solution. As a result, different models exhibit distinct phenomenological signatures and can be constrained through various experiments. In this work, we analyze the recent data from the COHERENT experiment, along with results from dark matter (DM) direct detection experiments such as XENONnT, LUX-ZEPLIN, and PandaX-4T, and place new constraints on three benchmark models. Additionally, we set constraints from a performed analysis of TEXONO data and discuss the prospects of improvement in view of the next-generation DM direct detection DARWIN experiment.

We propose a new haloscope geometry that can arbitrarily increase the resonator volume for a given target axion mass. This geometry consists of closely packed, overlapping coaxial cavities operating as a single resonator. While the resonant frequency is still determined by the dimensions of the individual “cells,” the strong interactions between the cells encourage the entire “beehive” to oscillate in phase, a phenomenon expected of tightly coupled harmonic oscillators. This synchronization behavior allows the construction of a singly connected large volume resonator at high frequency by simply increasing the number of the cells. Using direct numerical simulations, we verify the existence of a global eigenmode that has a high (40%) form factor in a 169-element beehive resonator. The resonant frequency of the eigenmode is tunable by moving the center rods laterally in unison. The form factor is very tolerant to dimensional deviations and misalignment as a result of mode hybridization due to strong coupling. The beehive haloscope inherits many appealing properties from the conventional coaxial cavity: a high quality factor, compatibility with a solenoid magnet, and ease of fabrication, tuning, and coupling. We argue that this geometry is an excellent candidate for high-mass axion searches covering the post-inflationary parameter space ($>5\mathrm{GHz}$).

We study leptogenesis from the decay of the lightest sterile neutrino in the scotogenic model with a scalar dark matter candidate. Our analysis focuses on the possible exponential suppression of washouts for sizable values of the inert Higgs mass and the crucial role of some spectator processes for this to happen. We show that leptogenesis can be successful for TeV-scale masses of the lightest sterile neutrino for both, thermal and zero, initial abundances of the neutrinos, without resorting to quasidegenerate neutrinos. Moreover, leptogenesis is viable for Yukawa couplings of the heavier sterile neutrinos large enough to yield observable charged lepton flavor violation (CLFV) processes in current and planned experiments.