Milky Way (MW) satellites exhibit a diverse range of internal kinematics, reflecting in turn a diverse set of subhalo density profiles. These profiles include large cores and dense cusps, which any successful dark matter model must explain simultaneously. A plausible driver of such diversity is self-interactions between dark matter particles (SIDM) if the cross section passes the threshold for the gravothermal collapse phase at the characteristic velocities of the MW satellites. In this case, some of the satellites are expected to be hosted by subhalos that are still in the classical SIDM core phase, while those in the collapse phase would have cuspy inner profiles, with a SIDM-driven intermediate mass black hole (IMBH) in the center as a consequence of the runaway collapse. We develop an analytical framework that takes into account the cosmological assembly of halos and is calibrated to previous simulations; we then predict the timescales and mass scales ($M_{\mathrm{BH}}$) for the formation of IMBHs in velocity-dependent SIDM (vdSIDM) models as a function of the present-day halo mass, $M_0$. Finally, we estimate the region in the parameter space of the effective cross section and $M_0$ for a subclass of vdSIDM models that result in a diverse MW satellite population as well as their corresponding fraction of SIDM-collapsed halos and those halos’ inferred IMBH masses. We predict the latter to be in the range $0.1–1000M_{\odot }$ with a $M_{\mathrm{BH}}-M_0$ relation that has a similar slope, but lower normalization, than the extrapolated empirical relation of supermassive black holes found in massive galaxies.

We complement a previous work [Fabiola Fortuna et al., Effective field theory analysis of dark matter-standard model interactions with spin one mediators, J. High Energy Phys. 02 (2021) 223.] using an effective field theory framework of dark matter and standard model interactions, with spin-one mediators, exploring a wider dark matter mass range, up to 6.4 TeV. We again use bounds from different experiments: relic density, direct detection experiments, and indirect detection limits from the search of gamma-ray emissions and positron fluxes. Additionally, in this paper we add collider constraints by the ATLAS Collaboration in the monojet analysis. Moreover, here we tested our previous results in the light of the aforementioned ATLAS data, which turns out to be the most restrictive for light dark matter masses (as expected), $m_{\mathrm{DM}}<M_Z/2$. We obtain a larger range of solutions for the operators of dimension 5, OP1 and OP4, where masses above 43 GeV and 30 GeV [except for the $Z$-resonance region, $\sim (M_Z\pm {\mathrm{\Gamma }}_Z)/2$], respectively, are allowed. In contrast, the operator of dimension 6, OP3, has viable solutions for masses $\gtrsim 190\mathrm{GeV}$. For the combination of OP1 and OP3 we obtain solutions (for masses larger than 140 GeV or 325 GeV) that depend on the relative sign between the operators.

We examine the dual graph representation of simplicial manifolds in causal dynamical triangulations (CDT) as a means to build observables and propose a new representation based on the finite element methods (FEM). In particular, with the application of FEM techniques, we extract the (low-lying) spectrum of the Laplace-Beltrami (LB) operator on the Sobolev space $H^1$ of scalar functions on piecewise flat manifolds and compare them with corresponding results obtained by using the dual graph representation. We show that, except for nonpathological cases in two dimensions, the dual graph spectrum and spectral dimension do not generally agree, neither quantitatively nor qualitatively, with the ones obtained from the LB operator on the continuous space. We analyze the reasons for this discrepancy and discuss its possible implications on the definition of generic observables built from the dual graph representation.

We revisit the four-point function of super gluons in ${\mathrm{AdS}}_5\times S^3$ and show how the integrand of a generalized Mellin transform satisfies the $U(1)$ decoupling identity, Bern-Carrasco-Johansson relations and color-kinematic duality, in a way that directly mirrors the analogous flat space relations. We unmix the spectrum of double-trace operators at large $N$ and find all anomalous dimensions at leading order which follow a very simple pattern, as in other theories with hidden conformal symmetries.

The anisotropy of pressure arises due to the various complex phenomena that happen inside the neutron star (NS). In this study, we calculate the degree of anisotropy inside the NS using the scalar pressure anisotropy model. Macroscopic properties such as mass, radius, compactness, redshift, tidal deformability, the moment of inertia, and surface curvature (SC) are computed for the anisotropic NS with the equation of states spanning from relativistic to nonrelativistic cases. The variation of SC as the functions of the above-mentioned quantities are computed by changing the degree of anisotropy. Pressure anisotropy has significant effects on the magnitude of SC. The relations between the canonical $\mathrm{SC}-\mathrm{\Lambda }$ and $\mathrm{SC}-\overline{I}$ are studied. From the GW170817 tidal deformability data, we constraints the magnitude of SC are found to be ${\mathrm{SC}}_{1.4}({10}^{14})={3.44}_{-1.0}^{+0.4},{2.85}_{-1.20}^{+0.62},{2.52}_{-1.02}^{+0.61}$ for ${\lambda }_{\mathrm{BL}}=0.0$, 1.0, and 2.0, respectively.

The adiabatic growth of a central massive black hole could compress the surrounding dark matter halo, leading to a steeper profile of the dark matter halo. This phenomenon is called adiabatic compression. We investigate the adiabatic compression of wave dark matter—a light bosonic dark matter candidate with its mass smaller than a few eV. Using the adiabatic theorem, we show that the adiabatic compression leads to a much denser wave dark matter halo similar to the particle dark matter halo in the semiclassical limit. The compressed wave halo differs from that of the particle halo near the center where the semiclassical approximation breaks down, and the central profile depends on dark matter and the central black hole mass as they determine whether the soliton and low angular momentum modes can survive over the astrophysical timescale without being absorbed by the black hole. Such a compressed profile has several astrophysical implications. As one example, we study the gravitational waves from the inspiral between a central intermediate-mass black hole and a compact solar-mass object within the wave dark matter halo. Due to the enhanced mass density, the compressed wave dark matter halo exerts stronger dynamical friction on the orbiting object, leading to the dephasing of the gravitational waves. The pattern of dephasing is distinctive from that of inspirals in the particle dark matter halo because of the difference in density profile and because of the relatively suppressed dynamical friction force, originating from the wave nature of dark matter. We investigate the prospects of future gravitational wave detectors, such as the Laser Interferometer Space Antenna, and identify physics scenarios where the wave dark matter halo can be reconstructed from gravitational wave observations.

We present measurements of the first to fourth moments of the lepton mass squared $q^2$ of $B\to X_c\ell {\overline{\nu }}_{\ell }$ decays for $\ell =e$, $\mu$ and with $X_c$ a hadronic system containing a charm quark. These results use a sample of electron-positron collisions at the $\mathrm{\Upsilon }(4S)$ resonance corresponding to $62.8{\mathrm{fb}}^{-1}$ of integrated luminosity and collected by the Belle II 2 experiment in 2019 and 2020. To identify the $X_c$ system and reconstruct $q^2$, one of the $B$ mesons from an $\mathrm{\Upsilon }(4S)\to B\overline{B}$ decay is fully reconstructed in a hadronic decay mode using a multivariate $B$ tagging algorithm. We report raw and central moments for $q^2>1.5{\mathrm{GeV}}^2/c^4$ up to $q^2>8.5{\mathrm{GeV}}^2/c^4$, probing up to 77% of the accessible $B\to X_c\ell {\overline{\nu }}_{\ell }$ phase space. This is the first measurement of moments in the experimentally challenging range of $[1.5,2.5]{\mathrm{GeV}}^2/c^4$. The results can be used for a new determination of $|V_{cb}|$ using inclusive $B\to X_c\ell {\overline{\nu }}_{\ell }$ decays.

We investigate multipartite entanglement for quantum states of $3D$ space geometry, described via generalized random spin networks with fixed areas, in the context of background independent approaches to quantum gravity. We focus on entanglement negativity as a well defined witness of quantum correlations for mixed states, in our setting describing generic subregions of the boundary of a quantum $3D$ region of space. In particular, we consider a generic tripartition of the boundary of an open spin network state and we compute the typical Rényi negativity of two boundary subregions $A$ and $B$ immersed in the environment $C$, explicitly for a set of simple open random spin network states. We use the random character of the spin network to exploit replica and random average techniques to derive the typical Rényi negativty via a classical generalized Ising model correspondence generally used for random tensor networks in the large bond regime. For trivially correlated random spin network states, with only local entanglement between spins located on the network edges, we find that typical log negativity displays a holographic character, in agreement with the results for random tensor networks, in large spin limit. When nonlocal bulk entanglement between intertwiners at the vertices is considered the negativity increases, while at the same time the holographic scaling is generally perturbed by the bulk contribution.

Motivated by the Bose et al.-Matletto-Vedral (BMV) proposal for detecting quantum superposition of spacetime geometries, we study a toy model of a quantum entanglement generation between two spins (qubits) mediated by a relativistic free scalar field. After time evolution, spin correlation is generated through the interactions with the field. Because of the associated particle creation into an open system, the quantum state of spins is partially decohered. In this paper, we give a comprehensive study of the model based on the closed time path formalism, focusing on relativistic causality and quantum mechanical complementarity. We calculate various quantities such as spin correlations, entanglement entropies, mutual information and negativity, and study their behaviors in various limiting situations. In particular, we calculate the mutual information of the two spins and compare it with spin correlation functions. In some cases, its inequality relation improves the trade-off relation between the fringe visibility and the distinguishability (which-way information) by giving a stronger upper bound on the visibility. We also discuss why no quantum entanglement can be generated unless both spins are causally affected by one another while spin correlations are generated.

Expanding edges in quantum Hall systems can become a simulator of quantum $1+1$ dimensional expanding universes. In these systems, edge excitations are represented as a chiral scalar field in curved spacetimes. We investigate Hawking radiation and entanglement behavior predicted by this model assuming that the expansion law of the edge region corresponds to a de Sitter universe. As observable quantities for the quantum field, local spatial modes associated with detection regions are introduced using window functions for the field, and their correlations are evaluated. We found the impact of Hawking radiation caused by the edge expansion on autocorrelation functions of the local modes, and confirmed that entanglement death due to Hawking radiation occurs. This behavior of entanglement is related to “quantum to classical transition” in cosmic inflations.

There have been debates in the literature about the existence of the first overtone in the ringdown of GW150914. We develop a novel Bayesian framework to reanalyze the data of this event, by incorporating a new technique, the “rational filter” that can clean particular modes from the ringdown signal. We examine the existence of the first overtone in GW150914 from multiple novel perspectives. First, we confirm that the estimates of the remnant black hole mass and spin are more consistent with those obtained from the full inspiral-merger-ringdown signal when including the first overtone at an early stage of the ringdown (right after the inferred signal peak); such improvement fades away at later times. Second, we formulate a new way to compare the ringdown models with and without the first overtone by calculating the Bayes factor at different times during the ringdown. We obtain a Bayes factor of 600 at the time when the signal amplitude reaches its peak. The Bayes factor decreases sharply when moving away from the peak time and eventually oscillates around a small value when the overtone signal is expected to have decayed. Third, we clean the fundamental mode from the ringdown of GW150914 and estimate the amplitudes of the modes using the filtered data with Markov chain Monte Carlo (MCMC). The inferred amplitude of the fundamental mode is $\sim 0$ whereas the amplitude of the first overtone remains almost unchanged, implying that the filtered data is consistent with a first-overtone-only template. Similarly, if we remove the first overtone from the GW150914 data, the filtered data are consistent with a fundamental-mode-only template. Finally, after removing the fundamental mode, we use MCMC to infer the remnant black hole mass and spin from the first overtone alone. We find the posteriors are still informative and consistent with those inferred from the fundamental mode. The conclusions are also verified through simulations in Gaussian noise using a GW150914-like numerical relativity waveform.

We discuss, in the context of alternative theories of gravity with nonminimal coupling between matter and curvature, if inflationary solutions driven by a single scalar field can be reconciled with the swampland conjectures about the emergence of de Sitter solutions in string theory. We find that the slow-roll conditions are incompatible with the swampland conjectures for a fairly generic inflationary solution in such alternative theories of gravity.

Field perturbations of a curved background spacetime generally propagate not only at the speed of light but also at all smaller velocities. This so-called Hadamard tail contribution to wave propagation is relevant in various settings, from classical self-force calculations to communication between quantum particle detectors. One method for calculating this tail contribution is by integrating the homogeneous wave equation using characteristic initial data on the light cone. However, to the best of our knowledge, this method has never been implemented before except in the special case of conformally flat spacetimes, where null geodesics emanating from a point do not cross. In this work, we implement this method on Plebański-Hacyan spacetime, ${\mathbb{M}}_2\times {\mathbb{S}}^2$, a black hole toy model which has caustics. We obtain new results in this spacetime by calculating the Hadamard tail of a scalar field everywhere where it is defined (namely, in the maximal normal neighborhood of an arbitrary point) and investigate how it varies for various values of the coupling constant. This serves as a proof-of-concept for the characteristic initial data method on spacetimes where null geodesics emanating from a point do cross.

In this article we present an alternative formalism for the inflationary phenomenology of rescaled Einstein-Gauss-Bonnet models which are in agreement with the GW170817 event. By constraining the propagation velocity of primordial tensor perturbations, an approximate form for the time derivative of the scalar field coupled to the Gauss-Bonnet density is extracted. In turn, the overall degrees of freedom decrease and, similar to the case of the canonical scalar field, only one scalar function needs to be designated, while the other is extracted from the continuity equation of the scalar field. We showcase explicitly that the slow-roll indices can be written in a closed form as functions of three dimensionless parameters, namely $x=\frac{1}{2\alpha }(\frac{\kappa {\xi }^{\prime }}{{\xi }^{\prime \prime }}{)}^2$, $\beta =8H^2{\xi }^{\prime \prime }$ and $\gamma =\frac{{\xi }^{\prime }{\xi }^{\prime \prime \prime }}{{{\xi }^{\prime \prime }}^2}$ and in turn, we prove that the Einstein-Gauss-Bonnet model can in fact produce a blue-tilted tensor spectral index if the condition $\beta \ge 1$ is satisfied, which is possible only for Einstein-Gauss-Bonnet models with ${\xi }^{\prime \prime }({\varphi }_k)>0$. Afterwards, a brief comment on the running of the spectral indices is made where it is shown that $a_{\mathcal{S}}(k_{*})$ and $a_{\mathcal{T}}(k_{*})$ in the constrained case are approximately of the order $\mathcal{O}({10}^{-3})$, if not smaller. Last but not least, we examine the conditions under which the swampland criteria are satisfied. We connect the tracking condition related to scalar field theories with the present models, and we highlight the important feature of the models we propose that the tracking condition can be satisfied only if the swampland criteria are simultaneously satisfied, however the cases with $\xi \sim 1/V$ and $\xi \sim V$ are excluded, as they cannot describe the inflationary era properly. Also, even though the swampland criteria can be in agreement with a blue-tilted tensor spectral index, we prove that there exists no model that respects the tracking condition while at the same time it manifests a blue-tilted tensor spectrum. We also discuss the preheating and reheating era implications and also issues related to the energy spectrum of primordial gravitational waves.

The mass and spin of black holes (BHs) in binary systems may change due to the infall of gravitational-wave (GW) energy down the horizons. For spinning BHs, this effect enters at 2.5 post-Newtonian (PN) order relative to the leading-order energy flux at infinity. There is currently a discrepancy in the literature in the expressions of these horizon fluxes in the test-body limit at 4PN order (relative 1.5PN order). Here, we model the horizon absorption as tidal heating in an effective worldline theory of a spinning particle equipped with tidally induced quadrupole and octupole moments. We match the tidal response to analytic solutions of the Teukolsky equation in a scattering scenario and obtain general formulas for the evolution of mass and spin. We then specialize to the case of aligned-spin–quasicircular binaries, obtaining the corresponding contributions to the GW phasing through 4PN order. Importantly, we find that the number of GW cycles due to horizon fluxes with masses observed by LIGO-Virgo-KAGRA detectors is about 2–3 orders of magnitude smaller than the other contributions to the phasing at the same PN order. Furthermore, in the test-body limit, we find full agreement with results obtained earlier from BH perturbation theory, with a small mass in an equatorial circular orbit treated as a source perturbing the Kerr metric. Thus, we weigh in on one side of the previous discrepancy.

We consider coupled dark energy (CDE) cosmologies, where dark matter particles feel a force stronger than gravity, due to the fifth force mediated by a scalar field which plays the role of dark energy. We perform for the first time a tomographic analysis of coupled dark energy, where the coupling strength is parametrized and constrained in different redshift bins. This allows us to verify which data can better constrain the strength of the coupling and how large the coupling can be at different epochs. First, we employ cosmic microwave background data from Planck, the Atacama Cosmology Telescope (ACT) and South Pole Telescope (SPT), showing the impact of different choices that can be done in combining these datasets. Then, we use a range of low redshift probes to test CDE cosmologies, both for a constant and for a tomographic coupling. In particular, we use for the first time data from weak lensing (the KiDS-1000 survey), galaxy clustering (BOSS survey), and their combination, including 3x2pt galaxy-galaxy lensing cross-correlation data. We do not find evidence for nonzero coupling, either for a constant or tomographic case. A nonzero coupling is however still in agreement with current data. For CMB and background datasets, a tomographic coupling allows for $\beta$ values up to one order of magnitude larger than in previous works, in particular at $z<1$. The use of 3x2pt analysis then becomes important to constrain $\beta$ at low redshifts, even when coupling is allowed to vary: for 3x2pt we find, at $0.5<z<1$, $\beta ={0.018}_{-0.011}^{+0.007}$, comparable to what CMB and background datasets would give for a constant coupling. This makes upcoming galaxy surveys potentially powerful probes to test CDE models at low redshifts. We find a smaller tension in $H_0$ and $S_8$ when the coupling is allowed to vary, although this is rather due to an increase in their uncertainties. We also see that our model is penalized by a Bayesian ratio model comparison with respect to $\mathrm{\Lambda }\mathrm{CDM}$, which is still favored by current data.

The kinetic Sunyaev-Zeldovich (kSZ) effect will be an important source of cosmological and astrophysical information in upcoming surveys of the cosmic microwave background (CMB). However, the kSZ effect will also act as the dominant source of noise for several other measurements that use small angular scales in CMB temperature maps, since its blackbody nature implies that standard component separation techniques cannot be used to remove it from observed maps. In this paper, we explore the idea of “de-kSZing”: constructing a template for the late-time kSZ effect using external surveys of large-scale structure, and then subtracting this template from CMB temperature maps in order to remove some portion of the kSZ signal. After building intuition for general aspects of the de-kSZing procedure, we perform forecasts for the de-kSZing efficiency of several large-scale structure surveys, including BOSS, DESI, Roman, MegaMapper, and PUMA. We also highlight potential applications of de-kSZing to cosmological constraints from the CMB temperature power spectrum, CMB lensing reconstruction, and the moving-lens effect. While our forecasts predict achievable de-kSZing efficiencies of 10%–20% at best, these results are specific to the de-kSZing formalism adopted in this work, and we expect that higher efficiencies are possible using improved versions of this formalism.