6062 research outputs found
Sort by
Pulsar kicks in ultralight dark matter background induced by neutrino oscillation
No full textThe interaction of neutrinos with ultralight scalar and vector dark matter backgrounds induce a modification of the neutrino dispersion relation. The effects of this modification are reviewed in the framework of asymmetric emission of neutrinos from the supernova core, and, in turn, of pulsar kicks. We consider the neutrino oscillations, focusing in particular to active-sterile conversion. The ultralight dark matter induced neutrino dispersion relation contains a term of the form δΩ · p̂, where δΩ is related to the ultralight dark matter field and p̂ is the unit vector along the direction of neutrino momentum. The relative orientation of p with respect to δΩ affects the mechanism for the generation of the observed pulsar velocities. We obtain the resonance condition for the active-sterile neutrino oscillation in ultralight dark matter background and calculate the star parameters in the resonance surface so that both ultralight scalar and vector dark matter backgrounds can explain the observed pulsar kicks. The asymmetric emission of neutrinos in presence of ultralight dark matter background results gravitational memory signal which can be probed from the future gravitational wave detectors such as adLIGO (advanced LIGO), adVIRGO (advanced VIRGO), DECIGO (DECi-hertz Interferometer Gravitational wave Observatory), BBO (Big Bang Observer), and ET (Einstein Telescope). We also establish a relation between the ultralight dark matter parameters and the Lorentz and CPT invariance violation parameters
From high-z protoclusters to local BCGs: Challenges for simulations
Get PDF<p>Talk at a meeting.</p>
Open quantum system approach to the gravitational decoherence of spin-<math display="inline"><mrow><mn>1</mn><mo>/</mo><mn>2</mn></mrow></math> particles
No full textThis paper investigates the decoherence effect resulting from the interaction of squeezed gravitational waves with a system of massive particles in spatial superposition. This paper investigates the decoherence effect resulting from the interaction of squeezed gravitational waves with a system of massive particles in spatial superposition. We first employ the open quantum system approach to obtain the established decoherence in a spatial superposition of massive objects induced by squeezed gravitational waves. Subsequently, we focus on the spin-1/2 particle system, and our analysis reveals that the decoherence rate depends on both the squeezing strength and the squeezing angle of the gravitational waves. Our results demonstrate that squeezed gravitational waves with squeezing strengths of rp≥1.2 and a squeezing angle of φp=π/2 can induce a 1% decoherence within 1 s free falling of a cloud of spin-1/2 particles. This investigation sheds light on the relationship between squeezed gravitational waves and the coherence of spatial superposition states in systems of massive particles and their spin. The dependence of decoherence on squeezing strength and, in the case of spin-1/2 particles, on the squeezing angle paves the way for further exploration and understanding of the quantum-gravity connection. We suggest that such an experimental setup could also be employed to eventually investigate the level of squeezing effect (and hence quantum-related properties) of gravitational waves produced in the early universe from inflation
CosmiXs: cosmic messenger spectra for indirect dark matter searches
No full textThe energy spectra of particles produced from dark matter (DM) annihilation or decay are one of the fundamental ingredients to calculate the predicted fluxes of cosmic rays and radiation searched for in indirect DM detection. We revisit the calculation of the source spectra for annihilating and decaying DM using the Vincia shower algorithm in Pythia to include QED and QCD final state radiation and diagrams for the EW corrections with massive bosons, not present in the default Pythia shower model. We take into account the spin information of the particles during the entire EW shower and the off-shell contributions from massive gauge bosons. Furthermore, we perform a dedicated tuning of the Vincia and Pythia parameters to LEP data on the production of pions, photons, and hyperons at the Z resonance and discuss the underlying uncertainties. To enable the use of our results in DM studies, we provide the tabulated source spectra for the most relevant cosmic messenger particles, namely antiprotons, positrons, γ rays and the three neutrino flavors, for all the fermionic and bosonic channels and DM masses between 5 GeV and 100 TeV, on github
Cosmic topology. Part IIa. Eigenmodes, correlation matrices, and detectability of orientable Euclidean manifolds
No full textIf the Universe has non-trivial spatial topology,observables depend on both the parameters of the spatial manifold and the position and orientation of the observer.In infinite Euclidean space, most cosmological observables arise from the amplitudes of Fourier modes of primordial scalar curvature perturbations.Topological boundary conditions replace the full set of Fourier modes with specific linear combinations of selected Fourier modes as the eigenmodes of the scalar Laplacian.We present formulas for eigenmodes in orientable Euclidean manifolds with the topologies E–E, E, E, E, and E that encompass the full range of manifold parameters and observer positions, generalizing previous treatments.Under the assumption that the amplitudes of primordial scalar curvature eigenmodes are independent random variables, for each topology we obtain the correlation matrices of Fourier-mode amplitudes (of scalar fields linearly related to the scalar curvature) and the correlation matrices of spherical-harmonic coefficients of such fields sampled on a sphere, such as the temperature of the cosmic microwave background (CMB).We evaluate the detectability of these correlations given the cosmic variance of the observed CMB sky. We find that topologies where the distance to our nearest clone is less than about 1.2 times the diameter of the last scattering surfaceof the CMB give a correlation signal that is larger than cosmic variance noise in the CMB.This implies that if cosmic topology is the explanation of large-angle anomalies in the CMB, then the distance to our nearest clone is not much larger than the diameter of the last scattering surface.We argue that the topological information is likely to be better preserved in three-dimensional data, such as will eventually be available from large-scale structure surveys
Cosmic Radiation Effects in LiteBIRD
No full text<p>LiteBIRD, a dedicated space-born experiment set to launch in the 2030s, aims to detect large-scale B-mode anisotropy of the linear polarization of the cosmic microwave background (CMB) as predicted by inflation theory. Operating from the second Lagrangean point of the Sun-Earth system, LiteBIRD will survey the sky across 15 frequency bands. However, the mission faces challenges associated with cosmic ray radiation, which can potentially degrade scientific data. Of particular concern is the energy loading onto the focal plane, a significant source of systematics. This study aims to provide an initial estimation for this effect on the High Frequency (HFT) telescope. It employs Geant4 simulations to assess the impact of cosmic rays, including Galactic Cosmic Rays and eruptive solar energetic particles, considering the space radiation environment at L2. These insights contribute to the ongoing refinement of LiteBIRD's instrumentation for robust and accurate measurements in the cosmic microwave background.</p>
Introduction to noncommutative field and gauge theory
No full textThese are lecture notes for an introductory course on noncommutative field and gauge theory. We begin by reviewing quantum mechanics as the prototypical noncommutative theory, as well as the geometrical language of standard gauge theory. Then, we review a specific approach to noncommutative field and gauge theory, which relies on the introduction of a derivations-based differential calculus. We focus on the cases of constant and linear noncommutativity, e.g., the Moyal spacetime and the so-called , respectively. In particular, we review the scalar field theory and the gauge theory on such noncommutative spaces. Finally, we discuss noncommutative spacetime symmetries from both the observer and particle point of view. In this context, the twist approach is reviewed and the -Minkowski model is discussed
Note Illustrative della Carta geologica d'Italia alla scala 1:50.000 F. 184 Mirandola, Servizio Geologico d'Italia - ISPRA
No full text<p>Note illustrative redatte per il Foglio geologico n. 184 Mirandola della Carta Geologica d'Italia alla scala 1:50.000. 156 pp.</p>
Carta Geologica d'Italia alla scala 1:50.000, F. 180 Salsomaggiore Terme. Geologia di sottosuolo
No full text<p>Foglio geologico di sottosuolo alla scala 1:50.000 basato su rilevamenti alla scala 1:25.000 (eseguiti tra il 1992 e il 1999) comprensivo di legenda, schemi a cornice, sezioni geologiche.</p>
I Primi 20 Minuti
Get PDF<p>Gioco da tavolo per 4 giocatori. Simula la nucleosintesi dubito dopo il big bang</p>