We derive the nucleon-nucleon interaction from the Skyrme model using the instanton and product approximations to skyrmion dynamics. In doing so, we also calculate the classical potential and metric for skyrmion dynamics in each of the approximations. This is the first time they have been compared in detail and the results show major disagreements between the approximations. We derive the eight low-energy nucleon-nucleon interaction potentials and compare them with the Paris model. For the instanton approximation we find strong negative isoscalar and isovector spin-orbit potentials, matching phenomenological models and our geometric intuition. Results for the other potentials are mixed, in part due to the zero pion mass limit used in this approximation.

Analysis based on the energy spectrum of noninteracting bosons shows that, under the circumstance of parallel rotation and magnetic field, charged bosons form a Bose-Einstein condensate because of the lift of the Landau level degeneracy by rotation [Y. Liu and I. Zahed, Phys. Rev. Lett. 120, 032001 (2018)]. In this work, we study the interaction effect on the ground state of this Bose-Einstein condensate of charged bosons from the viewpoint of spontaneous symmetry breaking. We employ a minimal model for charged bosons with repulsive self-interaction. We find that the ground state of such a Bose-Einstein condensate is a supergiant quantum vortex, i.e., a quantized vortex with a large circulation. The size of the vortex is as large as the system size. The low-energy dispersion of the excitation spectra exhibits quadratic behavior, which is an anisotropic realization of the type-II Goldstone boson. Our study may give some implications to off-central relativistic heavy ion collisions, where large vorticity and magnetic fields can be generated.

The cosmological constant is not necessarily small in the early universe. If a scalar field obtains a vacuum expectation value after a phase transition (PT), a possibly large cosmological constant could present before PT. The early cosmological constant (ECC) and the PT process may be detectable from dark radiation (DR) today, such as in the cosmic axion background. We show that for a broad class of DR models, the DR density and spectrum are significantly modified by the presence of an ECC. From the density and the spectrum of the DR today, we can deduce the temperature and the strength of the PT.

We use long-run, high-resolution hydrodynamics simulations to compute the multiwavelength light curves (LCs) from thermal disk emission around accreting equal-mass supermassive black hole (BH) binaries, with a focus on revealing binary eccentricity. LCs are obtained by modeling the disk thermodynamics with an adiabatic equation of state, a local blackbody cooling prescription, and corrections to approximate the effects of radiation pressure. We find that modulation of multiband LCs on the orbital time scale are generally in phase (to within $\sim 2\%$ of a binary orbital period), but they contain pulse substructure in the time domain that is not necessarily reflected in BH accretion rates $\dot{M}$. We thus predict that binary-hosting active galactic nucleus (AGN) will exhibit highly correlated, in-phase, periodic brightness modulations in their low-energy disk emission. However, detectability of these modulations in multiwavelength observing campaigns could be compromised because observed stochastic variability in AGNs typically has a higher amplitude than our proposed signal. It is possible that observations over temporal baselines of many binary periods may make the signal more prominent, but this would need to be analyzed carefully. If jet emission is predicted by $\dot{M}$, then we predict a weaker correlation with low-energy disk emission due to the differing subpeak structure. For the binary parameters we explore, we show that LC variability due to hydrodynamics likely dominates Doppler brightening for all equal-mass binaries with disk Mach numbers $\lesssim 20$. A promising signature of eccentricity is weak or absent “lump” periodicity. We find hints that a significant lag exists between $\dot{M}$ and low-energy disk emission for circular binaries, but they are in phase for eccentric binaries, which might explain some “orphan” blazar flares with no $\gamma$-ray counterpart.

The QCD axion is one of the most compelling candidates to explain the dark matter abundance of the Universe. With its extremely small mass ($\ll 1\mathrm{eV}/c^2$), axion dark matter interacts as a classical field rather than a particle. Its coupling to photons leads to a modification of Maxwell’s equations that can be measured with extremely sensitive readout circuits. ${\text{DMRadio-m}}^3$ is a next-generation search for axion dark matter below $1\mathit{\mu }\mathrm{eV}$ using a $>4\mathrm{T}$ static magnetic field, a coaxial inductive pickup, a tunable LC resonator, and a DC-SQUID readout. It is designed to search for QCD axion dark matter over the range $20\mathrm{neV}\lesssim m_a{c}^2\lesssim 800\mathrm{neV}$ ($5\mathrm{MHz}<\nu <200\mathrm{MHz}$). The primary science goal aims to achieve Dine-Fischler-Srednicki-Zhitnitsky sensitivity above $m_a{c}^2\approx 120\mathrm{neV}$ (30 MHz), with a secondary science goal of probing Kim-Shifman-Vainshtein-Zakharov axions down to $m_a{c}^2\approx 40\mathrm{neV}$ (10 MHz).

It is known that mixed quantum states are highly entropic states of imperfect knowledge (i.e., incomplete information) about a quantum system, while pure quantum states are states of perfect knowledge (i.e., complete information) with vanishing von Neumann entropy. In this paper, we propose an information geometric theoretical construct to describe and, to a certain extent, understand the complex behavior of evolutions of quantum systems in pure and mixed states. The comparative analysis is probabilistic in nature, it uses a complexity measure that relies on a temporal averaging procedure along with a long-time limit, and is limited to analyzing expected geodesic evolutions on the underlying manifolds. More specifically, we study the complexity of geodesic paths on the manifolds of single-qubit pure and mixed quantum states equipped with the Fubini-Study metric and the Sjöqvist metric, respectively. We analytically show that the evolution of mixed quantum states in the Bloch ball is more complex than the evolution of pure states on the Bloch sphere. We also verify that the ranking based on our proposed measure of complexity, a quantity that represents the asymptotic temporal behavior of an averaged volume of the region explored on the manifold during the evolution of the systems, agrees with the geodesic length-based ranking. Finally, focusing on geodesic lengths and curvature properties in manifolds of mixed quantum states, we observed a softening of the complexity on the Bures manifold compared to the Sjöqvist manifold.

In addition to the well-known $B\to D^{(*)}\ell {\nu }_{\ell }$ decays, semileptonic $B_s\to D_s^{(*)}\ell {\nu }_{\ell }$ processes offer the possibility to determine the Cabibbo-Kobayashi-Maskawa matrix element $|V_{cb}|$. We implement the dispersive matrix approach to describe the hadronic form factors (FFs) for the $B_s\to D_s^{(*)}$ transition in the whole kinematical range, starting from recent lattice QCD computations at large values of the four-momentum transfer. We extract $|V_{cb}|$ from the experimental data, obtaining $|V_{cb}|\times {10}^3=(41.7\pm 1.9)$ from $B_s\to D_s\ell {\nu }_{\ell }$ and $|V_{cb}|\times {10}^3=(40.7\pm 2.4)$ from $B_s\to D_s^{*}\ell {\nu }_{\ell }$ decays. After averaging with the values of $|V_{cb}|$ obtained from the $B\to D^{(*)}$ channels [G. Martinelli et al., Phys. Rev. D 105, 034503 (2022); G. Martinelli et al., arXiv:2109.15248.], we get $|V_{cb}|\times {10}^3=(41.2\pm 0.8)$, which is compatible with the most recent inclusive estimate $|V_{cb}{|}_{\mathrm{incl}}\times {10}^3=42.16\pm 0.50$ [M. Bordone et al., Phys. Lett. B 822, 136679 (2021).] at the $1\sigma$ level. In addition we test the lepton flavor universality by computing the $\tau /\ell$ ratios of the total decay rates (where $\ell$ is a light lepton), obtaining $R(D_s)=0.298(5)$ and $R(D_s^{*})=0.250(6)$. We also address the issue of the $SU(3{)}_F$ symmetry breaking by comparing the hadronic FFs entering the semileptonic $B\to D^{(*)}$ and $B_s\to D_s^{(*)}$ channels.

Searches for neutrinoless double-beta decay continue to expand our understanding of the lepton sector, with experiments now pursuing ton-scale target masses with sensitivity to $m_{\beta \beta }$ covering the allowed parameter space for the inverted neutrino mass ordering. Continued searches for this rare decay will require scalable detector technologies to achieve significant increases in the target mass beyond the ton scale, in order to probe the normal ordering region. This work explores the concept of searching for neutrinoless double-beta decay in a 10 kton-scale liquid argon time projection chamber (LArTPC) located deep underground and doped with percent-level quantities of xenon. We discuss the design requirements, background mitigation, and detector R&D needs and considerations for deployment in a modified DUNE far detector module. We find that such a detector could reach $m_{\beta \beta }$ sensitivity at the 2–4 meV range with xenon doping at 2% if significant background reductions can be achieved.

We construct on-shell $\mathcal{N}=2$ nonlinear sigma models on $SO(2N)/U(N)$ and $Sp(N)/U(N)$ by holomorphically embedding the models in the hyper-Kähler nonlinear sigma model on the cotangent bundle of the Grassmann manifold $T^{*}{G}_{2N,N}$ in the $\mathcal{N}=1$ superspace formalism. We apply the moduli matrix formalism to the mass-deformed nonlinear sigma models on the quadrics to study three-pronged junctions by using a recently proposed diagram method.

By utilizing the thin shell approximation, we investigate the behavior of radial timelike geodesics in a black hole to white hole bouncing scenario with a mass (de)amplification relation. We show that those geodesics lose energy after crossing the transition surface if the white hole mass is less than the black hole mass and vice versa. That is, the bounded timelike radial geodesics become closer to the event horizon in the mass decreasing direction. We then show that by tracing a finite amount of bouncing cycles along the mass decreasing direction, all bounded radial geodesics can be squeezed into the range of the stretched horizon while the black hole and white hole are still massive. Those highly squeezed geodesics are problematic since there exists a Planck-scale blueshift between them and the regular infalling trajectories. We also discuss the possible implication and rescues.

Based on entropy considerations and the arrow of time Penrose argued that the Universe must have started in a special initial singularity with vanishing Weyl curvature. This is often interpreted to be at odds with inflation. Here we argue just the opposite, that Penrose’s persuasions are in fact consistent with inflation. Using the example of power law inflation, we show that inflation begins with a past null singularity, where Weyl tensor vanishes when the metric is initially exactly conformally flat. This initial state precisely obeys Penrose’s conditions. The initial null singularity breaks $T$-reversal spontaneously and picks the arrow of time. It can be regulated and interpreted as a creation of a universe from nothing, initially fitting in a bubble of Planckian size when it materializes. Penrose’s initial conditions are favored by the initial $O(4)$ symmetry of the bubble, selected by extremality of the regulated Euclidean action. The predicted observables are marginally in tension with the data, but they can fit if small corrections to power law inflation kick in during the last $60e$-folds.

An inconsistency between the theoretical analysis and numerical calculations of the relativistic $r$-modes has puzzled the neutron star community since Kojima’s finding of the continuous part in the $r$-mode oscillation spectrum in 1997. In this paper, after a brief review of the Newtonian $r$-mode theory and of the literature devoted to the continuous spectrum of $r$-modes, we apply our original approach to the study of relativistic oscillation equations. Working within the Cowling approximation, we derive the general equations, governing the dynamics of discrete relativistic $r$-modes for both barotropic (isentropic) and nonbarotropic stars. A detailed analysis of the obtained equations in the limit of extremely slow stellar rotation rate reveals that, because of the effect of inertial reference frame-dragging, the relativistic $r$-mode eigenfunctions and eigenfrequencies become nonanalytic functions of the stellar angular velocity, $\mathrm{\Omega }$. We also derive the explicit expressions for the $r$-mode eigenfunctions and eigenfrequencies for very small values of $\mathrm{\Omega }$. These expressions explain the asymptotic behavior of the numerically calculated eigenfrequencies and eigenfunctions in the limit $\mathrm{\Omega }\to 0$. All the obtained $r$-mode eigenfrequencies take discrete values in the frequency range, usually associated with the continuous part of the spectrum. No indications of the continuous spectrum, at least in the vicinity of the Newtonian $l=m=2$ $r$-mode frequency $\sigma =-4/3$, are found.

In this paper, we calculate the QCD nonperturbative contributions of the neutrino-quark tensor operators to the neutrino magnetic moments by matching onto the chiral perturbation theory at low energies. These nonperturbative contributions can be compared to the perturbative ones, which are induced from one-loop mixing when performing the renormalization group evolutions from $\mu =m_W$ down to $\mu =2\mathrm{GeV}$. We then constrain the dipole and tensor Wilson coefficients of the low-energy neutrino effective field theory (LNEFT) separately from the neutrino-electron scattering with Borexino data and coherent elastic neutrino-nucleus scattering ($\mathrm{CE}\nu \mathrm{NS}$) with COHERENT data to show the competition between these two contributions, at the renormalization scales $\mu =2\mathrm{GeV}$ and $\mu =m_W$ in the $\overline{\mathrm{MS}}$ scheme. In the neutrino-electron scattering, it is found that the nonperturbative contributions dominate for the coefficients involving up and down quarks, while they are expected to be of the same order of magnitude as the perturbative contributions for the coefficients involving strange quarks. As for constraints in the $\mathrm{CE}\nu \mathrm{NS}$, the tensor operators can contribute to the process through either direct or indirect ways. As a result, the indirect contributions including nonperturbative and perturbative parts for all couplings become negligible in comparison to the direct ones. As the nonperturbative contributions crucially depend on the value of $c_T$, its inputs will affect the extraction of limits on the tensor LNEFT Wilson coefficients. We compute the upper bounds on these coefficients with $c_T$ quoting from the model and lattice estimates.

The new measurement of the $W$ boson mass performed by the CDF experiment at the Tevatron shows a significant deviation not only with the expectation in the Standard Model but also with other precision measurements performed at LEP, the Tevatron, and the LHC. We nevertheless take this new measurement at face value and interpret it as an effect of new physics. We particularly try to link it with other possible anomalies such as the recent muon $g-2$ and consider a scenario that addresses some shortcomings of the Standard Model. We show that a version of a model with two doublets and a light pseudoscalar Higgs fields, supplemented by a stable isosinglet fermion, can simultaneously explain the possible $M_W$ and $(g-2{)}_{\mu }$ anomalies and accounts for the weakly interacting massive particle that could be responsible of the dark matter in the universe.

Semi-inclusive processes are very promising to investigate $XYZ$ hadrons at the next generation of electron-hadron facilities, because they generally boast higher cross sections. We extend our formalism of exclusive photoproduction to semi-inclusive final states. The inclusive production cross sections for charged axial-vector $Z$ states from pion exchange are predicted. We isolate the contribution of $\mathrm{\Delta }$ resonances at small missing mass. Production near threshold is shown to be enhanced roughly by a factor of two compared to the exclusive reaction. We benchmark the model with data of semi-inclusive $b_1^{\pm }$ production.

We provide compact formulas for the heavy quark structure functions $F_2^{q\overline{q}}(x,Q^2)$ and $F_L^{q\overline{q}}(x,Q^2)$, with $q=c$, $b$, and $t$, in $e^{-}p$ interaction with respect to the behavior of the gluon density at the next-to-leading order approximation and present ratios $R^{q\overline{q}}=F_L^{q\overline{q}}/F_2^{q\overline{q}}$ for these quarks. To do this, we obtain a fitted form of the heavy quark coefficient functions for deep-inelastic lepton-hadron scattering at a wide range of $Q^2$ values. The obtained numerical results are compared with experimental data from HERA and with the results from the Kharzeev-Levin-Nardi model and the MSTW2008 predictions.

We perform general-relativistic simulations of self-gravitating black hole disks in which the spin of the black hole is significantly tilted (45° and 90°) with respect to the angular momentum of the disk and the disk–to–black hole mass ratio is 16–28%. The black holes are rapidly spinning with dimensionless spins up to $\sim 0.97$. These are the first self-consistent hydrodynamic simulations of such systems, which can be prime sources for multimessenger astronomy. In particular tilted black-hole-disk systems lead to (i) black hole precession, (ii) disk precession and warping around the black hole, (iii) earlier saturation of the Papaloizou-Pringle instability compared to aligned/antialigned systems, although with a shorter mode growth time scale, (iv) acquisition of a small black-hole kick velocity, (v) significant gravitational-wave emission via various modes beyond, but as strong as, the typical (2,2) mode, and (vi) the possibility of a broad alignment of the angular momentum of the disk with the black hole spin. This alignment is not related to the Bardeen-Petterson effect and resembles a solid body rotation. Our simulations suggest that any electromagnetic luminosity from our models may power relativistic jets, such as those characterizing short gamma-ray bursts. Depending on the black-hole-disk system scale the gravitational waves may be detected by LIGO/Virgo, LISA and/or other laser interferometers.

One of the most promising strategies to test gravity in the strong-field, large curvature regime is gravitational spectroscopy: the measurement of black hole quasinormal modes from the ringdown signal emitted in the aftermath of a compact binary coalescence, searching for deviations from the predictions of general relativity. This strategy is only effective if we know how quasinormal modes of black holes are affected by modifications of general relativity; and if we know this for rotating black holes, since binary coalescences typically lead to black holes with spins $J/M^2\sim 0.7$. In this article, we compute for the first time the gravitational quasinormal modes of rotating black holes up to second order in the spin in a modified gravity theory. We consider Einstein-dilaton Gauss-Bonnet gravity, one of the simplest theories which modifies the large-curvature regime of gravity and which can be tested with black hole observations. To enhance the domain of validity of the spin expansion, we perform a Padé resummation of the quasinormal modes. We find that when the second order in spin is not included, the effect of gravity modifications may be seriously underestimated. A comparison with the general relativistic case suggests that this approach should be accurate up to spins $\sim 0.7$; therefore, our results can be used in the data analysis of ringdown signals.

We study the thermodynamic properties of a static electrically charged spherical thin shell in $d$ dimensions by imposing the first law of thermodynamics on the shell. The shell is at radius $R$, inside it the spacetime is Minkowski, and outside it the spacetime is Reissner-Nordström. We obtain that the shell thermodynamics is fully described by giving two additional reduced equations of state, one for the temperature and another for the thermodynamic electrostatic potential. We choose the equation of state for the temperature as essentially a power law in the gravitational radius $r_{+}$ with exponent $a$, such that the $a=1$ case gives the temperature of a shell with black hole thermodynamic properties, and for the electrostatic potential we choose an equation of state characteristic of a Reissner-Nordström spacetime. The entropy of the shell is then found to be proportional to $A_{+}^a$, where $A_{+}$ is the gravitational area corresponding to $r_{+}$, with the exponent $a$ obeying $a>0$ to have a physically reasonable entropy. We are then able to perform the black hole limit $R=r_{+}$, find the Smarr formula for $d$-dimensional electrically charged black holes, and generically recover the thermodynamics of a $d$-dimensional Reissner-Nordström black hole. We further study the intrinsic thermodynamic stability of the shell with the chosen equations of state. We obtain that for $0<a\le \frac{d-3}{d-2}$ all the configurations of the shell are thermodynamically stable, for $\frac{d-3}{d-2}<a<1$ stability depends on the mass and electric charge, for $a=1$ the configurations are unstable, unless the shell is at its own gravitational radius, i.e., at the black hole limit, in which case it is marginally stable, and that for $1<a<\infty$ all configurations are unstable. Rewriting the stability conditions with variables that can be measured in the laboratory, it is found that the sufficient condition for the stability of these shells is when the isothermal electric susceptibility ${\chi }_{p,T}$ is positive, marginal stability happening when this quantity is infinite, and instability, and thus depart from equilibrium, arising for configurations with a negative electric susceptibility.