The sensitivity of continuous gravitational-wave (CW) searches for unknown neutron stars (NSs) is limited by their parameter space breadth. To fit within reasonable computing budgets, hierarchical schemes are used to identify interesting candidates using affordable methods. The resulting sensitivity depends on the number of candidates selected to follow-up. In this work, we present a novel framework to evaluate the effectiveness of stochastic CW follow-ups. Our results allow for a significant reduction of the computing cost of pyfstat, a well-established follow-up method. We also simplify the setup of multistage follow-ups by removing the need for parameter-space metrics. The study was conducted on Gaussian and real O3 Advanced LIGO data covering both isolated and binary sources. These results will have a positive impact on the sensitivity of all-sky searches in the forthcoming observing runs of the LIGO-Virgo-KAGRA collaboration.

We analyze the orbital dynamics of spherical test bodies in “black hole surrounded by dark matter halo” spherically symmetric spacetimes. When the test body pulsates periodically (such as a variable star), altering its quadrupole tensor, Melnikov’s method shows that its orbital dynamics presents homoclinic chaos near the corresponding unstable circular orbits however small the oscillation amplitude is. Since for supermassive black holes the period of revolution of a star near the innermost stable circular orbit roughly spans time intervals from minutes to hours, the formalism can be applied in principle to the astrophysical scenario of a pulsating (variable) star inspiraling into a supermassive black hole, including the black hole SgrA* at the center of our Galaxy. The chaotic nature of its orbit, due to pulsation, is imprinted in the redshift time series of the emitted light and can, in principle, be observed in the corresponding light curves and even in gravitational-wave signals detected by future observatories such as the Laser Inteferometer Space Antenna. Also, although periodic with respect to the star’s proper time, the chaotic orbital motion will produce an erratic light curve (and gravitational-wave signal) in terms of observed, coordinate time. Although our results were obtained for a specific exact solution, we argue that this phenomenon is generic for pulsating bodies immersed in black hole spacetimes surrounded by self-gravitating fluids.

We demonstrate the occurrence of sound speed resonances (SSR) in Gauss-Bonnet-coupled inflation across a wide range of coupling functions and parameters. After inflation, the damped oscillations of the inflaton around its potential minimum induces damped oscillations of the sound speed of tensor modes, leading to resonant amplification of the latter. Once the inflaton stabilizes around the minimum, the tensor sound speed reduces to unity (speed of light). In the context of multifield inflation, the sound speed oscillations can be followed by a second phase of inflation, resulting in a distinctive stochastic background of gravitational waves (GWs). We show that these GW signals can be probed by upcoming experiments such as SKA, DECIGO, and BBO depending on the duration of the second inflationary phase.

We develop theoretical methods for the implementation of creation and destruction operators in separate registers of a quantum computer, allowing for a transparent and dynamical creation and destruction of particle modes in second quantization in problems with variable particle number. We establish theorems for the commutation (anticommutation) relations on a finite memory bank and provide the needed symmetrizing and antisymmetrizing operators. Finally, we provide formulas in terms of these operators for unitary evolution under conventional two- and four-body Hamiltonian terms, as well as terms varying the particle number. In this formalism, the number of qubits needed to codify $n$ particles with $N_p$ modes each is of order $\mathcal{O}(n{\log }_2{N}_p)$. Such scaling is more efficient than the Jordan-Wigner transformation which requires $O(N_p)$ qubits, whenever there are a modest number of particles with a large number of states available to each (and less advantageous for a large number of particles with few states available to each).

We investigate the interactions of $(\overline{c}q)(\overline{c}q)/(ccq)(\overline{c}q)/(ccq)(ccq)$ dihadron systems based on a contact Lagrangian possessing the SU(3) flavor and SU(2) spin symmetries. Under the assumptions of two scenarios for the $J^P$ quantum numbers of $P_{\psi }^N(4440)$ and $P_{\psi }^N(4457)$ states, we obtain the parameters (${\tilde{g}}_s$, ${\tilde{g}}_a$) introduced from this contact Lagrangian. Then we include the SU(3) breaking effect by introducing a factor $g_x$, this quantity can be constrained by the experimental mass of $P_{\psi s}^{\mathrm{\Lambda }}(4338)$ state. We can reproduce the mass of $T_{cc}^f(3875)$ state with the parameters extracted from the observed $P_{\psi }^N$ states, the fairly good description of the masses of the observed $P_{\psi }^N/P_{\psi s}^{\mathrm{\Lambda }}/T_{cc}^f$ states motivates us to investigate the possible molecular candidates in the ${\overline{T}}_{cc}^f/P_{\psi c}^{\mathrm{\Lambda }}/H_{{\mathrm{\Omega }}_{ccc}c}^{\mathrm{\Lambda }}$ systems within the same framework. Then we proceed to discuss the existences of ${\overline{T}}_{cc\overline{s}}^{\theta }/P_{\psi cs}^N/H_{{\mathrm{\Omega }}_{ccc}cs}^N$ states by investigating the SU(3) breaking effects. Our results show that the states in the ${\overline{T}}_{cc\overline{s}}^{\theta }/P_{\psi cs}^N$ systems can hardly form bound states, while the states in the $H_{{\mathrm{\Omega }}_{ccc}cs}^N$ system can form bound states due to their larger reduced masses.

Levitated ferromagnets act as ultraprecise magnetometers, which can exhibit high quality factors due to their excellent isolation from the environment. These instruments can be utilized in searches for ultralight dark matter candidates, such as axionlike dark matter or dark-photon dark matter. In addition to being sensitive to an axion-photon coupling or kinetic mixing, which produce physical magnetic fields, ferromagnets are also sensitive to the effective magnetic field (or “axion wind”) produced by an axion-electron coupling. While the dynamics of a levitated ferromagnet in response to a dc magnetic field have been well studied, all of these couplings would produce ac fields. In this work, we study the response of a ferromagnet to an applied ac magnetic field and use these results to project their sensitivity to axion and dark-photon dark matter. We pay special attention to the direction of motion induced by an applied ac field, in particular, whether it precesses around the applied field (similar to an electron spin) or librates in the plane of the field (similar to a compass needle). We show that existing levitated ferromagnet setups can already have comparable sensitivity to an axion-electron coupling as comagnetometer or torsion balance experiments. In addition, future setups can become sensitive probes of axion-electron coupling, dark-photon kinetic mixing, and axion-photon coupling, for ultralight dark matter masses $m_{\mathrm{DM}}\lesssim \mathrm{feV}$.

We discuss the possibility of interpreting the recent experimental hints in favor of a 95 GeV resonance with extensions of the Standard Model featuring an extra Higgs doublet and SM scalar ($2\mathrm{HDM}+\mathrm{s}$) or pseudoscalar singlet ($2\mathrm{HDM}+\mathrm{a}$). We compare the possibility of reproducing the experimental anomalies with the theoretical constraints on the extended Higgs sector as well as complementary bounds coming from flavor physics and other colliders searchers. For both the $2\mathrm{HDM}+\mathrm{s}$ and $2\mathrm{HDM}+\mathrm{a}$ we will consider a generic natural flavor conserving (NFC) model as well as the customary type-I, -II, -X and -Y configurations of the Yukawa coupling to the BSM Higgs bosons. We find that no model is able to reproduce all experimental hints, and plot the $2\sigma$ C.L. favored regions in the parameter space.

In the framework of the Regge-eikonal model of hadron interaction based on the analyticity of the scattering amplitude, taking into account the hadron structure, a simultaneous analysis is carried out with 90 sets of data. These sets include data obtained at low energies ($\sqrt{s}>3.6\mathrm{GeV}$) and high energies at FNAL, ISR, $SP\overline{P}S$, TEVATRON, and LHC with 4326 experimental points, including the polarization data of analyzing power. The energy and momentum transfer dependence of separate sets of data is analyzed on the basis of the eikonalized Born amplitude, taking into account two additional anomalous terms. Different origins of the nonlinear behavior of the slope of the scattering amplitude are compared. No contribution from the hard Pomeron in elastic hadron scattering is found. The importance of odderon’s contribution is presented. The form and energy dependence of different terms of the cross-even and cross-odd parts of the elastic nucleon-nucleon scattering amplitude is determined in the framework of the high-energy general structure model. In this framework, using the electromagnetic and gravitomagnetic form factors, the differential cross sections in the Coulomb nuclear interference region and at large momentum transfer are described well simultaneously in a wide energy region. It is shown that the cross-even part, including the soft Pomeron and an additional term with a large slope, has energy dependence ${\ln }^2(s)$. The cross-odd part includes the maximal odderon term with ${\ln }^2(s)$ and an additional oscillation term with $\ln (s)$. It is shown that the additional terms with large slope are proportional to charge distributions, but the maximal odderon term and oscillation term are proportional to matter distributions. Additionally, a good description of proton-neutron differential scattering with 526 experimental points is obtained on the basis of the amplitudes taken from the analysis of $pp$ and $p\overline{p}$ scattering. An adequate description of the polarization data was also obtained.

In this paper we discuss how to use arborescent knots to construct entangled multiqubit states. We show that Bell-states, GHZ-states and cluster states can be constructed from such knots. The latter are particularly interesting since they form a base for the measurement-based quantum computers.

The mass spectra of light-flavor mesons are analyzed in a deformed anti–de Sitter/quantum chromodynamics (AdS/QCD) soft-wall model, driven by four distinct anomalous 5-dimensional mass corrections of the scalar field, coupled to Einstein-Hilbert gravity, from the QCD running coupling. Using the differential configurational entropy (DCE) underlying the families of pseudoscalar, axial-vector, scalar, and vector mesons, the mass spectra of heavier meson resonances with radial quantum numbers beyond the ones already in the summary table of Particle Data Group (PDG) are then estimated. This protocol merges AdS/QCD and experimental data in PDG through Regge-like trajectories. Some of the estimated meson resonances may be identified as further candidates omitted from the summary table in PDG.

We analyze the entanglement entropy between the black 0-brane solution to supergravity and its Hawking radiation. The black 0-brane admits a dual gauge theory description in terms of the matrix model for M-theory, named Banks Fischler Shenker Susskind (BFSS) theory, which is the theory of open strings on a collection of $N$ $D_0$-branes. Recent studies of the model have highlighted a mechanism of black hole evaporation for this system, based on the chaotic nature of the theory and the existence of flat directions. This paper further explores this idea, through the computation of the von Neumann entropy of Hawking radiation. In particular, we show that the expected Page curve is indeed reproduced, consistently with a complete recovery of information after the black hole has fully evaporated. A pivotal step in the computation is the definition of a Hilbert space that allows for a quantum mechanical description of partially evaporated black holes. We find that the entanglement entropy depends on the choice of a parameter, which can be interpreted as summarizing the geometric features of the black hole, such as the size of the resolved singularity and the size of the horizon.

We investigate the relation between the emergence of a dilaton in gapped (confining) field theories, and the presence of either complex fixed points or instabilities in the strongly coupled dynamics in two classes of bottom-up holographic models. We demonstrate that in one of the two classes there is a critical line of first-order phase transitions (at zero temperature) that terminates at a critical point. We calculate the mass spectrum of fluctuations of the associated regular gravity backgrounds, which we interpret as bound states in the dual field theories. In proximity to the second-order phase transition, we find a parametrically light scalar state, and its composition leads us to identify it as a dilaton.

We construct spherically symmetric dyonic black holes in a generalized Maxwell-Friedberg-Lee-Sirlin type model with a complex scalar doublet and a symmetry breaking potential for the real scalar field, minimally coupled to Einstein gravity in asymptotically flat space. We analyze the properties of the hairy black holes and determine their domain of existence. Our discussion focuses mostly on the case of a long-ranged massless real scalar field. Our results indicate that in this case, depending on the coupling constants, the resonant hairy dyonic black holes may bifurcate from Reissner-Nordström black holes at maximal chemical potential, while the limiting solutions at minimal chemical potential may be related to the Penney solution.

The scattering of electrically charged fermions on magnetic monopole leads to the Callan-Rubakov effect. We discuss some aspects of this problem for Abelian gauge theories with chiral fermions in a Dirac monopole background. In some cases, it is possible to embed the theory in a non-Abelian gauge theory where the monopole is regularized as a ’t Hooft-Polyakov monopole. One theory of this kind is the $SU(N)$ chiral gauge theory with fermions in the representation $\square \square \oplus$ $\overline{\begin{array}{|c|}\hline \mathrm{\hspace{0.17em}\hspace{0.17em}}\\ \mathrm{\hspace{0.17em}\hspace{0.17em}}\\ \hline\end{array}}$$\hspace{0.17em}\oplus \hspace{0.17em}8\hspace{0.17em}\times \hspace{0.17em}\overline{\square }$, also called the “$\psi \chi \eta$” model, with an extra adjoint scalar that induces the abelianization of the gauge group. We examine this model in detail and provide a possible solution for the condensates around the monopole, the symmetry preserving boundary conditions, and discuss the particle scattering problem.

We investigate perturbations in a rotational and incompressible fluid flow. Interested in the phenomenon analogous to the black hole ergoregion instability, we verify the influence of the vorticity in the instability associated with this fluid system, in the presence of a region in which the fluid flow velocity is greater than the speed of the perturbation. With this aim, we compute the quasinormal modes of the system, using two different numerical methods, obtaining an excellent numerical agreement between them. We find that the vorticity tends to diminish the ergoregion instability of the system.

The temperature and polarization anisotropies of the cosmic microwave background have been used to set constraints on decaying dark matter models down to keV masses. In this work, we extend these limits down to the sub-keV mass range. Using principal component analysis, we estimate the lower bound on the decay lifetime for a basis of different dark matter masses and Standard Model final states, from which the bound on an arbitrary model can be calculated. We validate our principal component analysis using Markov chain Monte Carlo methods and Planck 2018 data. We perform a separate analysis for models decaying into photons below the hydrogen ionization threshold. We demonstrate that, for these models, the effect of energy deposition can be captured approximately by a single parameter, but the redshift dependence of the effect is very different from higher-energy injections; in particular, the perturbations to cosmic microwave background anisotropies are more sensitive to energy deposited around the time of recombination.

The stochasticity in galaxy clustering, the mismatch between the galaxy and underlying matter distributions, suppresses the matter-clustering amplitude reconstructed by the combination of galaxy autocorrelation and galaxy-galaxy lensing cross-correlation. In this work, we solve the stochasticity systematics by parametrizing the cross-correlation coefficient $r(k)$ between the galaxy and matter distributions. We investigate the performance of 12 kinds of parametrization schemes against the cosmoDC2 and TNG300-1 galaxy samples over a wide range of redshifts and flux cuts. The two-parameter fits are found to describe the stochasticity up to $k_{\max }=0.9{\mathrm{Mpc}}^{-1}h$, while the best-performing quadratic scheme, $r_s^2(k)=1+c_{1}k+c_2{k}^2$, reaches better than 1% accuracy for both the direct $r_s^2(k)$ fit and reconstructing matter clustering. Then, we apply the accurate quadratic scheme to forecast the tomographic matter-clustering reconstruction by the combination of DESI-like $\mathrm{LRG}\times \mathrm{CSST}$-like cosmic shear. Depending on the assumption of stochasticity, we find that the neglect of a serious stochasticity would result in significant systematic bias in both the reconstruction and the inferred cosmological parameters, even if we adopt a scale cut of $k_{\max }=0.1{\mathrm{Mpc}}^{-1}h$. We demonstrate the necessity of including stochasticity in reconstruction and forecast that the reconstruction alone enables an $S_8$ constraint at about 1.5% precision, free from galaxy bias and stochasticity. We will validate our method for the DESI spectroscopic survey, and the analysis is expected to be complementary to the DESI cosmological constraint by baryonic acoustic oscillations and redshift space distortion.

In this paper we present new constraints on the velocity-independent cross section of keV-scale mass annihilating dark matter particles obtained with SRG/ART-XC after 4 full-sky surveys. These constraints are derived from observations of the Milky Way Halo, 33 Local Group spheroidal dwarf (dSph) galaxies and separately for the dSph galaxy Ursa Major III/UNIONS 1. The constraints from the Milky Way Halo are the strongest among others and among all available in literature for this class of dark matter models with particle masses from 4 to 15 keV.

Ultralight scalar fields can experience runaway “superradiant” amplification near spinning black holes, resulting in a macroscopic “axion cloud,” which slowly dissipates via continuous monochromatic gravitational waves. For a particular range of boson masses, $\mathcal{O}({10}^{-11}–{10}^{-10})\mathrm{eV}$, an axion cloud will radiate in the 10–100 kHz band of the levitated sensor detector (LSD). Using fiducial models of the mass, spin, and age distributions of stellar-origin black holes, we simulate the present-day Milky Way population of these hypothetical objects. As a first step toward assessing the LSD’s sensitivity to the resultant ensemble of gravitational wave signals, we compute the corresponding signal-to-noise ratios which build up over a nominal integration time of ${10}^7\mathrm{s}$, assuming the projected sensitivity of the 1 m LSD prototype currently under construction, as well as for future 10 m and 100 m concepts. For a 100 m cryogenic instrument, hundreds of resolvable signals could be expected if the boson mass $\mu$ is around $3\times {10}^{-11}\mathrm{eV}$, and this number diminishes with increasing $\mu$ up to $\approx 5.5\times {10}^{-11}\mathrm{eV}$. The much larger population of unresolved sources will produce a confusion foreground which could be detectable by a 10-m instrument if $\mu \in (3–4.5)\times {10}^{-11}\mathrm{eV}$ or by a 100-m instrument if $\mu \in (3–6)\times {10}^{-11}\mathrm{eV}$.