In this article, we study topological and noninertial effects on the motion of the two-dimensional Dirac oscillator in the presence of a uniform magnetic field and the Aharonov-Bohm potential. We obtain the Dirac equation that describes the model. Expressions for the wave functions and energy spectrum are derived. The energy spectrum of the oscillator as a function of the various physical parameters involved in the problem is rigorously studied. We estimate the phenomenological energy scale of the model based on upper bounds for string tension, as well as values for the angular momentum $J$ and the intergalactic magnetic fields found in the literature. Finally, we present some analogies between our results and others of the condensed matter physics.

We investigate the different large $N$ phases of a generalized Gross-Witten-Wadia (GWW) $U(N)$ matrix model. The deformation mimics the one-loop determinant of fermion matter with a particular coupling to gauge fields. In one version of the model, the GWW phase transition is smoothed out and it becomes a crossover. In another version, the phase transition occurs along a critical line in the two-dimensional parameter space spanned by the ’t Hooft coupling $\lambda$ and the Veneziano parameter $\tau$. We compute the expectation value of Wilson loops in both phases, showing that the transition is third order. A calculation of the $\beta$ function shows the existence of an IR stable fixed point.

We find a topologically nontrivial structure of the Nambu monopole in the two-Higgs-doublet model (2HDM), which is a magnetic monopole attached by two topologically stable $Z$ strings ($Z$ flux tubes) from two opposite sides. The structure is in sharp contrast to the topological triviality of the Nambu monopole in the Standard Model (SM), which is attached by a single nontopological $Z$ string. It is found that the Nambu monopole in the 2HDM possesses the same fiber-bundle structure as those of the ’t Hooft–Polyakov monopole and the Wu-Yang description of the Dirac monopole, as a result of the fact that the electromagnetic gauge field is well defined even inside the strings and is nontrivially fibered around the monopole, while the Nambu monopole in the SM is topologically trivial because electroweak gauge symmetry is restored at the core of the string. Consequently, the Nambu monopole in the 2HDM can be regarded as an embedding of the ’t Hooft–Polyakov monopole into the $SU(2{)}_W$ gauge symmetry, and the Dirac quantization condition always holds, which is absent for the Nambu monopole in the SM. Furthermore, we construct a dyon configuration attached with the two strings.

We study the dynamics of (i) neutral test particles, (ii) magnetically charged test particles, and (iii) test magnetic dipole around a regular Bardeen black hole surrounded by perfect fluid dark matter (PFDM). It has been shown how the magnetic charge of the black hole and the parameter of the surrounding PFDM can influence the innermost stable circular orbit (ISCO) radius of a test particle. We have found that the ISCO radius is strongly affected as a consequence of the combined effect of the magnetic charge parameter and the perfect fluid dark matter. The black hole magnetic charge parameter $g$ and the combined effect of perfect fluid dark matter can mimic the black hole rotation parameter up to $a/M\approx 0.9$. It has been observed that the ISCO for magnetic dipole disappears at the values exceeding the calculated upper value for the magnetic interaction parameter $\beta$. The upper limit decreases with the increase of both the dark matter and magnetic charge parameters. Finally, as an astrophysical application, we have analyzed degeneracy effects of spin of Kerr black holes and magnetic charge of regular Bardeen black holes for the different values of the dark matter parameter providing exactly the same value for ISCO radius of a magnetic dipole with the same value of the parameter $\beta =10.2$ of the magnetar called PSR J1745-2900 orbiting around supermassive black hole Sagittarius A*. It has been observed that the magnetic charge of the pure regular Bardeen black hole can mimic the spin of a Kerr black hole up to $a/M\simeq 0.8085$, while upper limit for the magnetic charge which may provide ISCO for the magnetic dipole is $g_{\text{upper}}\simeq 0.65M$. In the presence of PFDM with the parameter $\alpha =0.01(0.05)$, the upper limit for the magnetic charge decreases and equals to $g_{\text{upper}}\simeq 0.62M$ ($0.548M$) and consequently mimicker value for the spin parameter of black hole lies in the range of $a/M\in (0.0106÷0.8231)$ ($a/M\in (0.0816÷0.8595)$). We also show that the same values of the spin of Kerr black hole and the magnetic charge of regular Bardeen black hole surrounded by PFDM provide the same values for the ISCO radius of the chosen magnetar.

Massive neutrinos influence the background evolution of the Universe as well as the growth of structure. Being able to model this effect and constrain the sum of their masses is one of the key challenges in modern cosmology. Weak-lensing cosmological constraints will also soon reach higher levels of precision with next-generation surveys like LSST, WFIRST and Euclid. In this context, we use the massivenus simulations to derive constraints on the sum of neutrino masses $M_{\nu }$, the present-day total matter density ${\mathrm{\Omega }}_m$, and the primordial power spectrum normalization $A_s$ in a tomographic setting. We measure the lensing power spectrum as second-order statistics along with peak counts as higher-order statistics on lensing convergence maps generated from the simulations. We investigate the impact of multiscale filtering approaches on cosmological parameters by employing a starlet (wavelet) filter and a concatenation of Gaussian filters. In both cases peak counts perform better than the power spectrum on the set of parameters [$M_{\nu }$, ${\mathrm{\Omega }}_m$, $A_s$] respectively by 63%, 40% and 72% when using a starlet filter and by 70%, 40% and 77% when using a multiscale Gaussian. More importantly, we show that when using a multiscale approach, joining power spectrum and peaks does not add any relevant information over considering just the peaks alone. While both multiscale filters behave similarly, we find that with the starlet filter the majority of the information in the data covariance matrix is encoded in the diagonal elements; this can be an advantage when inverting the matrix, speeding up the numerical implementation. For the starlet case, we further identify the minimum resolution required to obtain constraints comparable to those achievable with the full wavelet decomposition and we show that the information contained in the coarse-scale map cannot be neglected.

We test the regime of validity of the one-loop galaxy bias for a wide variety of biased tracers. Our most stringent test asks the bias model to simultaneously match the galaxy-galaxy and galaxy-mass spectrum, using the measured nonlinear matter spectrum from the simulations to test the one-loop effects from the bias expansion alone. In addition, we investigate the relevance of short-range nonlocality and halo exclusion through higher-derivative and scale-dependent noise terms, as well as the impact of using coevolution relations to reduce the number of free fitting parameters. From comparing the validity and merit of these assumptions, we find that a four-parameter model (linear, quadratic, cubic nonlocal bias, and constant shot noise) with a fixed quadratic tidal bias provides a robust modeling choice for the auto power spectrum of the less massive halos in our set of samples and their galaxy populations [up to $k_{\max }=0.35h/\mathrm{Mpc}$ for a sample volume of $6(\mathrm{Gpc}/h{)}^3$]. For the more biased tracers, it is most beneficial to include scale-dependent noise. This is also the preferred option when considering combinations of the auto and cross power spectrum, which might be relevant in joint studies of galaxy clustering and weak lensing. We also test the use of perturbation theory to account for matter loops through gRPT, EFT, and the hybrid approach RESPRESSO. While all these have similar performance, we find the latter to be the best in terms of validity and recovered mean posterior values, in accordance with it being based partially on simulations.

We study the possibility to obtain cosmological late-time acceleration from a geometry changing with the scale, in particular, in the so-called multifractional theories with $q$-derivatives and with weighted derivatives. In the theory with $q$-derivatives, the luminosity distance is the same as in general relativity and, therefore, geometry cannot act as dark energy. In the theory with weighted derivatives, geometry alone is able to sustain a late-time acceleration phase without fine tuning, while being compatible with structure-formation and big-bang nucleosynthesis bounds. This suggests to extend the theory, in a natural way, from just small-scale to also large-scale modifications of gravity. Surprisingly, the Hausdorff dimension of spacetime is constrained to be close to the topological dimension 4. After arguing that this finding might not be a numerical coincidence, we conclude that present-day acceleration could be regarded as the effect of a new restoration law for spacetime geometry.

We perform a detailed parameter estimation study of binary black hole merger events reported by Zackay et al. [Phys. Rev. D 100, 023007 (2019)] and Venumadhav et al. [Phys. Rev. D 101, 083030 (2020)]. These are some of the faintest signals reported so far, and hence, relative to the loud events in the GWTC-1 catalog [B. P. Abbott et al. (LIGO Scientific and Virgo Collaborations), Phys. Rev. X 9, 031040 (2019)], the data should have lesser constraining power on their intrinsic parameters. Hence we examine the robustness of parameter inference to choices made in the analysis, as well as any potential systematics. We check the impact of different methods of estimating the noise power spectral density, different waveform models, and different priors for the compact object spins. For most of the events, the resulting differences in the inferred values of the parameters are much smaller than their statistical uncertainties. The estimation of the effective spin parameter ${\chi }_{\mathrm{eff}}$, i.e., the projection of the mass-weighted total spin along the angular momentum, can be sensitive to analysis choices for two of the sources with the largest effective spin magnitudes, GW151216 and GW170403. The primary differences arise from using a 3D isotropic spin prior: the tails of the posterior distributions should be interpreted with care and due consideration of the other data analysis choices.

The open charm strong decay widths and certain ratio of branching fractions of a charmed strange baryon ${\mathrm{\Xi }}_c(2970)$ are calculated in a ${}^3{P}_0$ model. The results are compatible with the latest experimental data. The theoretical ratio of decay branching fractions $R=\mathcal{B}[{\mathrm{\Xi }}_c(2970{)}^{+}\to {\mathrm{\Xi }}_c(2645{)}^0{\pi }^{+}]/\mathcal{B}[{\mathrm{\Xi }}_c(2970{)}^{+}\to {\mathrm{\Xi }}_c^{\prime 0}{\pi }^{+}]\approx 1.0$. The spin parity $J^P=1/2^{+}$ and $3/2^{+}$ for different assignments are analyzed. From the results of our calculation, ${\mathrm{\Xi }}_c(2970)$ can be interpreted as a $2S$-wave state with $J^P(s_l)=1/2^{+}(0)$. The distinctions between the $2S$-wave $n_{\rho }$- and $n_{\lambda }$-excitation states and between states with $s_l=0$ and $s_l=1$ and between states with total spin $1/2$ and $3/2(s_l=1)$ are also discussed.

We perform a comprehensive search for Standard Model extensions inspired by asymptotic safety. Our models feature a singlet matrix scalar field, three generations of vectorlike leptons, and direct links to the Higgs and flavor sectors via new Yukawa and portal couplings. A novel feature is that the enlarged scalar sector may spontaneously break lepton flavor universality. We provide a complete two-loop renormalization group analysis of the running gauge, Yukawa, and quartic couplings to find ultraviolet fixed points and the critical surface of parameters, i.e., the set of boundary conditions at the TeV scale for which models remain well-behaved and predictive up to the Planck scale without encountering Landau poles or instabilities. This includes templates for asymptotically safe Standard Model extensions that match the measured values of gauge couplings and the Higgs, top, and bottom masses. We further detail the phenomenology of our models covering production, decay, fermion mixing, anomalous magnetic moments, effects from scalar mixing and chiral enhancement, and constraints on model parameters from data. Signatures at proton-proton and lepton colliders, such as lepton flavor violation and displaced vertices, and the prospect for electric dipole moments or charged lepton-flavor-violating type processes are also indicated.

In spacetimes of any dimensionality, the massless particle states that can be created and destroyed by a field in a given representation of the Lorentz group are severely constrained by the condition that the invariant Abelian subgroup of the little group must leave these states invariant. A number of examples are given of the massless one-particle states that can be described by various tensor and spinor-tensor fields, and a speculation is offered for the general case.

We construct $bb\overline{u}\overline{d}$ states on lattice using non relativistic QCD (NRQCD) action for bottom and highly improved staggered quark (HISQ) action for the light up/down quarks. The NRQCD-HISQ tetraquark operators are constructed for “bound” $[bb][\overline{u}\overline{d}]$ and “molecular” $[b\overline{u}][b\overline{d}]$ states. Corresponding to these different operators, two different appropriately tuned light quark masses are needed to obtain the desired spectra. We explain this requirement of different $m_{u/d}$ in the light of relativized quark model involving Hartree-Fock calculation. The mass spectra of double bottom tetraquark states are obtained on MILC $N_f=2+1$ Asqtad lattices at three different lattice spacings. Variational analysis has been carried out to obtain the relative contribution of bound and molecular states to the energy eigenstates.

Motivated by the calculation of observables in the decays ${\mathrm{\Lambda }}_b\to {\mathrm{\Lambda }}_c({\frac{1}{2}}^{\pm })\ell \overline{\nu }$, we present a calculation of form factors in the quark model. Our scheme combines a spectroscopic model with the internal wave functions and the Bakamjian-Thomas (BT) relativistic formalism to get the wave functions in motion. In the heavy quark limit, the current matrix elements provide the Isgur-Wise (IW) function. This limit is covariant, satisfies a large set of sum rules, and has been successfully applied to mesons. On the other hand, for baryons, we meet difficulties using standard spectroscopic models. This leads us to propose a phenomenological model, a Q-pointlike-diquark model, nonrelativistic, with harmonic oscillator forces, giving both a reasonable low-lying spectrum and the expected slope of the IW function. To begin, we extract this slope from lattice QCD data and find it to be around ${\rho }_{\mathrm{\Lambda }}^2\sim 2$, that we use as a guideline. We are not able to reproduce the right ${\rho }_{\mathrm{\Lambda }}^2$ using certain typical standard $\text{linear}+\text{Coulomb}$ potential models, both with three quarks $Qqq$ or in a Q-pointlike-diquark picture. These difficulties seem to derive from the high sensitivity of ${\rho }_{\mathrm{\Lambda }}^2$ to the structure of the light quark subsystem in a relativistic scheme. Finally, we present our model, and fixing its parameters to yield the correct spectrum and ${\rho }_{\mathrm{\Lambda }}^2\sim 2$, we apply it to the calculation of observables. By studying Bjorken sum rule, we show that the inelastic IW function is large, and therefore, the transitions ${\mathrm{\Lambda }}_b\to {\mathrm{\Lambda }}_c({\frac{1}{2}}^{-},{\frac{3}{2}}^{-})\ell \overline{\nu }$ could be studied at LHCb. Interestingly, some observables in the $\tau$ case present zeroes for specific values of $q^2$ that could be tests of the Standard Model.

We studied the impact of future electron ion collider inclusive and semi-inclusive polarized deep inelastic scattering data will have on the determination of the helicity parton distributions. Supplementing the Monte Carlo sampling variant of the DSSV14 analysis with pseudodata on polarized inclusive and semi-inclusive electron-proton deep inelastic scattering with updated uncertainty estimates and for two different center-of-mass-system energies, $\sqrt{s}=44.7\mathrm{GeV}$ and $\sqrt{s}=141.4\mathrm{GeV}$, respectively, and on inclusive electron-helium collisions at $\sqrt{s}=115.2\mathrm{GeV}$, we find a remarkable improvement in the determination of the helicity distributions, especially at low parton momentum fraction $x$. While inclusive electron-proton data at the lowest energy configuration constrain significantly the gluon polarization down to $x\sim {10}^{-4}$, the higher energy configuration strengthens the constraint and extends it one decade further. On the other hand, semi-inclusive data achieves the hitherto elusive flavor separation for sea quarks that cannot be obtained from any other inclusive electromagnetic measurement. Collisions with helium complement inclusive proton measurements, pushing the constraints on the combined quark plus antiquark $u$, $d$ and $s$ polarizations to an unprecedented level.

Here we propose a minimal analog gravity setup and suggest how to select two surface gravity wave packets in order to mimic some key aspects of Hawking radiation from the horizon of nonrotating black holes. Our proposed setup, unlike the scattering problem conventionally studied, constitutes of a constant mean flow over a flat bathymetry, in which the two wave packets possess the same amount of wave action but equal and opposite (sign) amount of energy, thereby mimicking virtual particles created out of near horizon vacuum fluctuations. Attention is given to the physical mechanism relating to the signs of the wave action and energy norm with the wave’s intrinsic and total phase speeds. We construct narrow wave packets of equal wave action, the one with positive energy and group speed propagates against the mean flow and escapes from the black hole as Hawking radiation, while the other with negative energy and group speed is drifted by the mean flow and falls into it. Hawking’s prediction of low frequency mode amplification is satisfied in our minimal model by construction. We find that the centroid wave numbers and surface elevation amplitudes of the wave packets are related by simple analytical expressions.

$f(R)$ is a paradigmatic modified gravity theory that typifies extensions to General Relativity with new light degrees of freedom and hence screened fifth forces between masses. These forces produce observable signatures in galaxy morphology, caused by a violation of the weak equivalence principle due to a differential impact of screening among galaxies’ mass components. We compile statistical datasets of two morphological indicators—offsets between stars and gas in galaxies and warping of stellar disks—and use them to constrain the strength and range of a thin-shell-screened fifth force. This is achieved by applying a comprehensive set of upgrades to past work [H. Desmond et al., Phys. Rev. D 98, 064015 (2018); H. Desmond et al., Phys. Rev. D 98, 083010 (2018) ]: we construct a robust galaxy-by-galaxy Bayesian forward model for the morphological signals, including full propagation of uncertainties in the input quantities and marginalization over an empirical model describing astrophysical noise. Employing more stringent data quality cuts than previously we find no evidence for a screened fifth force of any strength $\mathrm{\Delta }G/G_{\mathrm{N}}$ in the Compton wavelength range 0.3–8 Mpc, setting a $1\sigma$ bound of $\mathrm{\Delta }G/G_{\mathrm{N}}<0.8$ at ${\lambda }_C=0.3\mathrm{Mpc}$ that strengthens to $\mathrm{\Delta }G/G_{\mathrm{N}}<3\times {10}^{-5}$ at ${\lambda }_C=8\mathrm{Mpc}$. These are the tightest bounds to date beyond the Solar System by over an order of magnitude. For the Hu-Sawicki model of $f(R)$ with $n=1$ we require a background scalar field value $f_{R0}<1.4\times {10}^{-8}$, forcing practically all astrophysical objects to be screened. We conclude that this model can have no relevance to astrophysics or cosmology.

The detection of Galactic binaries as sources of gravitational waves promises an unprecedented wealth of information about these systems but also raises several challenges in signal processing. In particular the large number of expected sources and the risk of misdetection call for the development of robust methods. We describe here an original nonparametric recovery of the imprint of Galactic binaries in measurements affected by instrumental noise typical of the space-based gravitational wave observatory LISA. This method, based on a denoising procedure, aims at separating from noise the sum of all signals coming from Galactic binaries. We assess the impact of various approaches based on sparse signal modeling and focus on adaptive structured block sparsity. We carefully show that a sparse representation of the interferometric measurement gives a reliable access to the total signal coming from Galactic binaries. In particular we check the successful fast recovery of the gravitational wave signal on a simple yet realistic example involving verification Galactic binaries recently proposed in LISA data challenges.

We study the inflationary generation of helical magnetic fields from the Riemann coupling with the electromagnetic field. Most models in the literature introduce nonminimal coupling to the electromagnetic fields with a scalar field, hence, breaking the conformal invariance. In this work, we show that nonminimal coupling to the Riemann tensor generates sufficient primordial helical magnetic fields at all observable scales. We explicitly show that one of the helical states decays while the other helical mode increases, leading to a net nonzero helicity. Our model has three key features: (i) the helical power spectrum has a slight red tilt for slow-roll inflation consistent with bounds from observations and free from backreaction problem, (ii) the energy density of the helical fields generated is at least one order of magnitude larger than the scalar-field-coupled models, and (iii) unlike the scalar-field-coupled models, the generated helical fields are insensitive to the reheating dynamics. We show that our model generates the magnetic field of strength 0.01 pG over the Mpc scale.

We present a new realization of the resonant production of primordial black holes as well as gravitational waves in a two-stage inflation model consisting of a scalar field $\varphi$ with an axion-monodromy-like periodic structure in the potential that governs the first stage and another field $\chi$ with a hilltoplike potential that dominates the second stage. The parametric resonance seeded by the periodic structure at the first stage amplifies the perturbations of both fields inside the Hubble radius. While the evolution of the background trajectory experiences a turn as the oscillatory barrier height increases, the amplified perturbations of $\chi$ remain as they are and contribute to the final curvature perturbation. It turns out that the primordial power spectrum displays a significant resonant peak on small scales, which can lead to an abundant production of primordial black holes. Furthermore, gravitational waves are also generated from the resonantly enhanced field perturbations during inflation, the amplitude of which may be constrained by future gravitational wave interferometers.

The exact nature of dark energy is currently unknown and its cosmological perturbations, when dark energy is assumed not to be the cosmological constant, are usually modeled as adiabatic. Here we explore the possibility that dark energy might have a nonadiabatic component and we examine how it would affect several key cosmological observables. We present analytical solutions for the growth rate and growth index of matter density perturbations and compare them to both numerical solutions of the fluid equations and an implementation in the Boltzmann code CLASS, finding that they all agree to well below one percent. We also perform a Monte Carlo analysis to derive constraints on the parameters of the nonadiabatic component using the latest cosmological data, including the temperature and polarization spectra of the cosmic microwave background as observed by Planck, the baryon acoustic oscillations, the Pantheon type Ia supernovae compilation and last, measurements of redshift space distortions (RSDs) of the growth rate of matter perturbations. We find that the amplitude of the nonadiabatic pressure perturbation is consistent with zero within $1\sigma$. Finally, we also present a new, publicly available, RSD likelihood for MONTE PYTHON based on the “Gold 2018” growth-rate data compilation.