arXiv subjects
Publications and source records attributed to Antonio Capolupo.
We discuss the necessity and the emergence of quantum reference frames when attempting to define a rest frame for mixed particles. We analyze the corresponding concept of frame dependent entanglement and how it could affect measurements on mixed mesons and neutrinos.
We show that, in the framework of quantum field theory in curved spacetime, the semiclassical energy-momentum tensor of the neutrino flavor vacuum fulfills the equation of state of dust and cold dark matter. We consider spherically symmetric spacetimes, and we demonstrate that, within the weak field approximation, the flavor vacuum contributes as a Yukawa correction to the Newtonian potential. This corrected potential may account for the flat rotation curves of spiral galaxies. In this perspective, neutrino mixing could contribute to dark matter
We show that the X17 vector boson, introduced to explain the ^8 Be anomalous decay, could play a crucial role in the explanation of the muon's (electron's) anomalous magnetic moment and the muonic Lamb shift. We further constrain the possible kinetic mixing with the U(1)_Y boson of the Standard Model by using the latest available data on the W boson mass.
We find a new solution to calculate the orbital periastron advance of a test body subject to a central gravitational force field, for relativistic theories and models beyond Einstein. This analitycal formula has general validity that includes all the post-Newtonian (PN) contributions to the dynamics and is useful for high-precision gravitational tests. The solution is directly applicable to corrective potentials of various forms, without the need for numerical integration. Later, we apply it to the Scalar Tensor Fourth Order Gravity (STFOG) and NonCommutative Geometry, providing corrections to the Newtonian potential of Yukawa-like form $V(r)=α\frac{e^{-βr}}{r}$, and we conduct the first analysis involving all the PN terms for these theories. The same work is performed with a Schwarzschild geometry perturbed by a Quintessence Field, leading to a power-law potential $V(r)=α_q {r}^q$. Finally, by using astrometric data of the Solar System planetary precessions and those of S2 star around Sgr A*, we infer new theoretical constraints and improvements in the bounds for $β$. The resulting simulated orbits turn out to be compatible with General Relativity.
We propose a novel neutron interferometry setup to explore the potential existence of mirror neutrons, a candidate for dark matter. Our work demonstrates that if mirror neutrons exist, neutrons will acquire an observable geometric phase due to mixing with these mirror counterparts. This geometric phase, detectable through our interferometric setup, could serve as a direct probe for the presence of mirror matter particles. Additionally, this investigation could shed light on unresolved issues in particle physics, such as the neutron lifetime puzzle. We discuss the setup's versatility and limitations, showing its capability to explore a wide range of parameters in neutron interferometry and potentially uncover new physics.
We reveal the presence of a new source of axial current due to the condensed vacuum generated by the spin-spin interaction. To show this, we consider a quartic Dirac Lagrangian containing a spin-spin interaction term, possibly originating from torsion in Einstein-Cartan-like theories. We use a mean field approach to analyze the quantized theory. We show that the diagonalization of the field Hamiltonian defines a new vacuum state, energetically favored with respect to the free vacuum. Such a vacuum, which is a condensate of particle-antiparticle pairs, is characterized by a nontrivial expectation value of the axial current operator. The new source of axial current, here obtained, can have effects both at the atomic level and at the astrophysical-cosmological level depending on the origin of the spin-spin interaction term. The condensate may affect the dark sector of the universe at cosmological level and the axial current originated by the vacuum condensate could be analyzed in next table top experiments on graphene
In the framework of quantum field theory, we analyze the neutrino oscillations in the presence of a torsion background. We consider the Einstein-Cartan theory and we study the cases of constant torsion and of linearly time dependent torsion. We derive new neutrino oscillation formulae which are depending on the spin orientation. Indeed the energy splitting induced by the torsion influences oscillation amplitudes and frequencies. This effect is maximal for values of torsion of the same order of the neutrino masses and for very low momenta, and disappears for large values of torsion. Moreover, neutrino oscillation is inhibited for intensities of torsion term much larger than neutrino masses and momentum. The modifications induced by torsion on the $CP$-asymmetry has been also presented. Future experiments, such as PTOLEMY, could provide insights into the effect shown here.
We analyze several phenomenological implications of a nonlocal generalization of quantum electrodynamics (QED). We compute the nonlocal corrections to the photon propagator up to one loop, and we show that nonlocality leads to a change of the Coulomb potential. We then investigate the ensuing modifications to the Lamb shift and to the electrostatic forces and comparing our results with the data from the muonic hydrogen anomaly, we set lower bounds on the nonlocality scales. We also discuss the running of the electromagnetic coupling for the nonlocal theory. The results obtained indicate that future experimental analyses on atomic phenomena, such as the Lamb shift, could allow to verify the presence of non-local effects on microscopic scales and impose effective limits on the non-locality scale.
We report on recent result according to which the fermion-fermion interaction mediated by axions and axion-like particles can be revealed by means of neutron interferometry. We assume that the initial neutron beam is split in two beams which are affected by differently oriented magnetic fields, in order that the phase difference depends only by the axion-induced interaction. In this way, the phase difference is directly related to the presence of axions.
We develop the quantum field theory of fermion mixing in curved spacetime and discuss the role of unitarily inequivalent representations in the particle interpretation of the theory. We derive general oscillation formulae and apply them to specific spcetimes of interest, such as spatially flat FRW metrics and the Schwarzschild spacetime. We exhibit the main deviations from the usual quantum mechanical approach.
We develop a notion of causal order on a generic manifold as independent of the underlying differential and topological structure. We show that sufficiently regular causal orders can be recovered from a distinguished algebra of sets, which plays a role analogous to that of topologies and $σ$ algebras. We then discuss how a natural notion of measure can be associated to the algebra of causal sets.
We study a nonlocal generalization of two flavor fermion mixing and compute the transition probability by means of the path integral formalism. In our treatment, we delocalize only the mixing term, and consider a perturbative interaction with a small mixing angle. The oscillation formula derived reduces to the correct local form when the appropriate limit is considered. We apply our formalism to some string-inspired delocalization kernels and discuss the phenomenological deviations from the local theory.
We analyze the boson mixing in curved spacetime and compute the expectation value of the energy-momentum tensor of bosons on the flavor vacuum in spatially flat Friedmann-Lemaitre-Robertson-Walker metrics. We show that the energy-momentum tensor of the flavor vacuum behaves as the effective energy-momentum tensor of a perfect fluid. Assuming a fixed de Sitter background, we show that the equation of state can assume values in the interval [-1, 1], and, in the flat spacetime limit has a value -1, which is the one of the dark energy. The results here presented show that vacuum of mixed bosons like neutrino super-partners, can represent a possible component of the dark energy of the Universe.
In this paper we constrain the sizes of hypothetical new weak forces by making use the data coming from the precession of Planets. We consider the weak field approximation of Scalar-Tensor Fourth Order Gravity (STFOG), which include several models of modified gravity. The form of the corrections to the Newtonian potential if of the form of Yukawa-like potential (5th force), i.e. $V(r) = α \dfrac{e^{-βr}}{r}$, where $α$ is the parameter related to the strength of the potential, and $β$ to the range of the force. The present data on periastron advance allow to infer a constraint on the free parameter of the gravitational models. Moreover, the Non-Commutative Spectral Gravity (NCSG) is also studied, being a particular case STFOG. Here we show that the precession shift of Planet allows to improve the bounds on parameter $β$ by several orders of magnitude. Finally such an analysis is studied to the case of power-like potential, referring in particular to deformation of the Schwarzschild geometry induced by a quintessence field, responsible of the present accelerated phase of the Universe.
We show that the discrepancy between the observed value of the muon anomalous moment and the standard model prediction can be explained in the framework of nonlocal theories. We compute the leading order and next to leading order nonlocal correction to the anomalous magnetic moment $α_{NL}$ and we find that it depends on the nonlocality scale $M_f$ and the fermion mass $m_f$ as $α_{NL} \propto m_f^2/M_f^2$. Such a dependence of the anomalous magnetic momentum allows to explain, in a flavor-blind nonlocality scale, why the observed anomalous magnetic moment of the electron is much closer to the standard model prediction, and permits to predict a large anomaly that should exist for the $τ$ particle. We also determine the lower bounds on the nonlocality scale, for both flavor-blind and flavor-dependent scenarios.
We discuss the relevance of quantum reference frames in the description of mixed particle states. We show that the notion of rest frame for mixed particles, which is classically ill-defined, can be introduced in the context of quantum frames. We discuss the possible phenomenological implications, displaying a new form of framedependent entanglement that characterizes reactions involving mixed particles.
We show that the study of neutrino capture on tritium, for non-relativistic neutrinos, can allow to distinguish among the various neutrino models, eventually prove the quantum field theory condensation effects and permit to test the hypothesis according to which the flavor vacuum energy gives a contribution to the dark matter of the universe. Indeed, we show that the capture rate depends on the neutrino model considered, and that it brings an imprint of the flavor vacuum condensate. Experiments like PTOLEMY, designed to reveal the cosmic neutrino background, then can give an indication of the existence of the dark matter component induced by neutrino mixing.
We analyze the geometric phase for neutrinos and we demonstrate that the geometric invariants associated to transitions between different neutrino flavors, for Majorana neutrinos, can depend on the representation of the mixing matrix and then are sensitive to the nature of neutrinos. The dependence of geometric invariants on the Majorana phase cannot be eliminated by a charged lepton rephasing transformation. By considering kinematic and geometric approach we also demonstrate that the Majorana phase is relevant in the projective Hilbert space. Geometric invariants can in principle be used as tools to distinguish between Dirac and Majorana neutrinos.