arXiv subjects

Marco Mancini

Publications and source records attributed to Marco Mancini.

18 recordsLinked to original sources

arXiv2025

Blind unblinding procedure for the PADME X17 data sample

The PADME experiment at the Frascati DA$\Phi$NE LINAC has performed a search for the hypothetical X17 particle, with a mass of around 17 MeV, by scanning the energy of a positron beam striking a fixed target. The X17 should be produced from the resulting $e^+e^-$ annihilation. Since the expected mass of this particle is only roughly known, data sidebands cannot be clearly defined. Furthermore, the need to keep the analysis blind to potentially sizable signal contributions prevents a clear assessment even of the quality of the data sample in this search. In light of these challenges, this paper presents an innovative strategy adopted by the PADME Collaboration to perform data quality checks without disclosing the X17 sample. Moreover, the procedure designed to eventually unblind the data is described, together with the statistical approach adopted to extract the limits on the coupling between the X17 and the Standard Model.

hep-ex↗

arXiv2023

Quick Guides for Use of the CompOSE Data Base

We present a combination of two quick guides aimed at summarizing relevant information about the CompOSE nuclear equation of state repository. The first is aimed at nuclear physicists and describes how to provide standard equation of state tables. The second quick guide is meant for users and describes the basic procedures to obtain customized tables with equation of state data. Several examples are included to help providers and users to understand and benefit from the CompOSE database.

nucl-th↗

arXiv2023

Modified Urca neutrino emissivity at finite temperature

Charged current neutrino-nucleon reactions, generally called Urca processes, are crucial actors of a neutron star's thermal evolution. The so-called direct processes show a pronounced threshold under which the reaction is kinematically suppressed. This suppression does not apply to "modified" Urca processes which involve interaction with an additional nucleon. Calculations of the modified Urca neutrino rates were established for cold neutron star matter and for dilute hot matter, in both cases under strong assumptions. In this paper, we revise the calculations of the modified Urca neutrino rates for dense and hot matter, and for different compositions. We study the influence of different approximations used in previous computations. We derive expressions for the rates of modified Urca neutrino emissivity within thermal field theory and perform the phase space integration numerically using mainly importance sampling Monte-Carlo techniques. The neutrino emissivity of modified and direct processes are established and compared. We find in particular that the modified Urca process is not necessarily suppressed with respect to the direct process above the threshold of the latter at moderate densities and temperatures, in contrast to what is generally assumed. Numerical results are confirmed by an estimation of the ratio of modified to direct Urca rates with a simple analytic approximation, thereby showing the regimes of suppression for the modified processes depending on temperature and density. These results show that modified Urca rates have to be considered carefully upon evaluating neutrino opacities in dense and warm matter.

nucl-th↗

arXiv2023

Status and Prospects of PADME

The Positron Annihilation to Dark Matter Experiment (PADME) was designed and constructed to search for dark photons ($A'$) in the process $e^+e^-\rightarrowγA'$, using the positron beam at the Beam Test Facility (BTF) at the National Laboratories of Frascati (LNF). Since the observation of an anomalous spectra in internal pair creation decays of nuclei seen by the collaboration at the ATOMKI institute, the PADME detector has been modified and a new data-taking run has been undertaken to probe the existance of the so-called ``X17" particle

hep-ex↗

arXiv2022

Resonant search for the X17 boson at PADME

We discuss the experimental reach of the Frascati PADME experiment in searching for new light bosons via their resonant production in positron annihilation on fixed target atomic electrons. A scan in the mass range around 17 MeV will thoroughly probe the particle physics interpretation of the anomaly observed by the ATOMKI nuclear physics experiment. In particular, for the case of a spin-1 boson, the viable parameter space can be fully covered in a few months of data taking.

hep-ph↗

arXiv2021

OPUS: an interoperable job control system based on VO standards

OPUS (Observatoire de Paris UWS System) is a job control system that aims at facilitating the access to analysis and simulation codes through an interoperable interface. The Universal Worker System pattern v1.1 (UWS) as defined by the International Virtual Observatory Alliance (IVOA) is implemented as a REST service to control the asynchronous execution of a job on a work cluster. OPUS also follows the recent IVOA Provenance Data Model recommendation to capture and expose the provenance information of jobs and results. By following well defined standards, the tool is interoperable and jobs can be run either through a web interface, or a script, and can be integrated to existing web platforms. Current instances are used in production by several projects at the Observatoire de Paris (CTA/H.E.S.S, MASER, CompOSE).

astro-ph.IM↗

arXiv2020

Improved neutrino-nucleon interactions in dense and hot matter for numerical simulations

Neutrinos play an important role in compact star astrophysics: neutrino-heating is one of the main ingredients in core-collapse supernovae, neutrino-matter interactions determine the composition of matter in binary neutron star mergers and have among others a strong impact on conditions for heavy element nucleosynthesis and neutron star cooling is dominated by neutrino emission except for very old stars. Many works in the last decades have shown that in dense matter medium effects considerably change the neutrino-matter interaction rates, whereas many astrophysical simulations use analytic approximations which are often far from reproducing more complete calculations. In this work we present a scheme which allows to incorporate improved rates, for charged current interactions, into simulations and show as an example some results for core-collapse supernovae, where a noticeable difference is found in the location of the neutrinospheres of the low-energy neutrinos in the early post-bounce phase.

astro-ph.HE↗

arXiv2020

Hanbury-Brown and Twiss bunching of phonons and of the quantum depletion in a strongly-interacting Bose gas

We report the realisation of a Hanbury-Brown and Twiss (HBT)-like experiment with a gas of strongly interacting bosons at low temperatures. The regime of large interactions and low temperatures is reached in a three-dimensional optical lattice and atom-atom correlations are extracted from the detection of individual metastable Helium atoms after a long free-fall. We observe a HBT bunching in the non-condensed fraction of the gas whose properties strongly deviate from the HBT signals expected for non-interacting bosons. In addition, we show that the measured correlations reflect the peculiar quantum statistics of atoms belonging to the quantum depletion and of the Bogoliubov phonons, i.e., of collective excitations of the many-body quantum state. Our results demonstrate that atom-atom correlations provide information about the quantum state of strongly-interacting particles, extending the interest of HBT-like experiments beyond the case of non-interacting particles.

cond-mat.quant-gas↗

arXiv2019

Momentum-space atom correlations in a Mott insulator

We report on the investigation of the three-dimensional single-atom-resolved distributions of bosonic Mott insulators in momentum-space. Firstly, we measure the two-body and three-body correlations deep in the Mott regime, finding a perfectly contrasted bunching whose periodicity reproduces the reciprocal lattice. In addition, we show that the two-body correlation length is inversely proportional to the in-trap size of the Mott state with a pre-factor in agreement with the prediction for an incoherent state occupying a uniformly filled lattice. Our findings indicate that the momentum-space correlations of a Mott insulator at small tunnelling is that of a many-body ground-state with Gaussian statistics. Secondly, in the Mott insulating regime with increasing tunnelling, we extract the spectral weight of the quasi-particles from the momentum density profiles. On approaching the transition towards a superfluid, the momentum spread of the spectral weight is found to decrease as a result of the increased mobility of the quasi-particles in the lattice. While the shapes of the observed spectral weight agree with the ones predicted by perturbative many-body calculations, the fitted mobilities are larger than the theoretical ones. This discrepancy is similar to that previously reported on the time-of-flight visibility.

cond-mat.quant-gas↗

arXiv2019

Two-body collisions in the time-of-flight dynamics of lattice Bose superfluids

We investigate two-body collisions occurring during the time-of-flight expansion of interacting three-dimensional lattice Bose superfluids. The number of collisions is extracted from the observed s-wave scattering halos located between the diffraction peaks of the superfluids. These faint halos can be monitored thanks to the large dynamical range in densities associated with detecting individual metastable Helium atoms. We monitor the number of collisions as a function of the total atom number and of the amplitude of the lattice, in a regime where the number of trapped atoms per lattice site is large. In addition, we introduce a classical model of collisions that quantitatively describes the experiment without adjustable parameters. Finally, the present work validates quantitatively the assumption of a ballistic expansion when investigating the Bose-Hubbard Hamiltonian with a unity occupation of the lattice.

cond-mat.quant-gas↗

arXiv2018

Anomaly Detection Models for IoT Time Series Data

Insitu sensors and Wireless Sensor Networks (WSNs) have become more and more popular in the last decade, due to their potential to be used in various applications of many different fields. As of today, WSNs are pretty much used by any monitoring system: from those that are health care related, to those that are used for environmental forecasting or surveillance purposes. All applications that make use of insitu sensors, strongly rely on their correct operation, which however, is quite difficult to guarantee. These sensors in fact, are typically cheap and prone to malfunction. Additionally, for many tasks (e.g. environmental forecasting), sensors are also deployed under potentially harsh weather condition, making their breakage even more likely. The high probability of erroneous readings or data corruption during transmission, brings up the problem of ensuring quality of the data collected by sensors. Since WSNs have to operate continuously and therefore generate very large volumes of data every day, the quality control process has to be automated, scalable and fast enough to be applicable to streaming data. The most common approach to ensure the quality of sensors data, consists in automated detection of erroneous readings or anomalous behaviours of sensors. In the literature, this strategy is known as anomaly detection and can be pursued in many different ways.

eess.SP↗

arXiv2018

Symbolic tensor calculus on manifolds: a SageMath implementation

These lecture notes present a method for symbolic tensor calculus that (i) runs on fully specified smooth manifolds (described by an atlas), (ii) is not limited to a single coordinate chart or vector frame, (iii) runs even on non-parallelizable manifolds and (iv) is independent of the symbolic backend used to perform calculus at the level of coordinate expressions. In addition to the main ideas, we discuss some details of the implementation in the open-source mathematics software system SageMath, which has been performed via the SageManifolds project.

gr-qc↗

arXiv2018

Single-atom-resolved probing of lattice gases in momentum space

Measuring the full distribution of individual particles is of fundamental importance to characterize many-body quantum systems through correlation functions at any order. Here we demonstrate the possibility to reconstruct the momentum-space distribution of three-dimensional interacting lattice gases atom-by-atom. This is achieved by detecting individual metastable Helium atoms in the far-field regime of expansion, when released from an optical lattice. We benchmark our technique with Quantum Monte-Carlo calculations, demonstrating the ability to resolve momentum distributions of superfluids occupying $10^5$ lattice sites. It permits a direct measure of the condensed fraction across phase transitions, as we illustrate on the superfluid-to-normal transition. Our single-atom-resolved approach opens a new route to investigate interacting lattice gases through momentum correlations.

cond-mat.quant-gas↗

arXiv2015

A compact ultranarrow high-power laser system for experiments with 578nm Ytterbium clock transition

In this paper we present the realization of a compact, high-power laser system able to excite the Ytterbium clock transition at 578 nm. Starting from an external-cavity laser based on a quantum dot chip at 1156 nm with an intra-cavity electro-optic modulator, we were able to obtain up to 60 mW of visible light at 578 nm via frequency doubling. The laser is locked with a 500 kHz bandwidth to a ultra-low-expansion glass cavity stabilized at its zero coefficient of thermal expansion temperature through an original thermal insulation and correction system. This laser allowed the observation of the clock transition in fermionic $^{173}$Yb with a < 50 Hz linewidth over 5 minutes, limited only by a residual frequency drift of some 0.1 Hz/s.

physics.optics↗

arXiv2015

Direct observation of coherent inter-orbital spin-exchange dynamics

We report on the first direct observation of fast spin-exchange coherent oscillations between different long-lived electronic orbitals of ultracold $^{173}$Yb fermions. We measure, in a model-independent way, the strength of the exchange interaction driving this coherent process. This observation allows us to retrieve important information on the inter-orbital collisional properties of $^{173}$Yb atoms and paves the way to novel quantum simulations of paradigmatic models of two-orbital quantum magnetism.

cond-mat.quant-gas↗

arXiv2014

Tensor calculus with open-source software: the SageManifolds project

The SageManifolds project aims at extending the mathematics software system Sage towards differential geometry and tensor calculus. Like Sage, SageManifolds is free, open-source and is based on the Python programming language. We discuss here some details of the implementation, which relies on Sage's parent/element framework, and present a concrete example of use.

gr-qc↗

arXiv2014

A one-dimensional liquid of fermions with tunable spin

Correlations in systems with spin degree of freedom are at the heart of fundamental phenomena, ranging from magnetism to superconductivity. The effects of correlations depend strongly on dimensionality, a striking example being one-dimensional (1D) electronic systems, extensively studied theoretically over the past fifty years. However, the experimental investigation of the role of spin multiplicity in 1D fermions - and especially for more than two spin components - is still lacking. Here we report on the realization of 1D, strongly-correlated liquids of ultracold fermions interacting repulsively within SU(N) symmetry, with a tunable number N of spin components. We observe that static and dynamic properties of the system deviate from those of ideal fermions and, for N>2, from those of a spin-1/2 Luttinger liquid. In the large-N limit, the system exhibits properties of a bosonic spinless liquid. Our results provide a testing ground for many-body theories and may lead to the observation of fundamental 1D effects.

cond-mat.quant-gas↗

arXiv2007

Decorated vertices with 3-edged cells in 2D foams: exact solutions and properties

The energy, area and excess energy of a decorated vertex in a 2D foam are calculated. The general shape of the vertex and its decoration are described analytically by a reference pattern mapped by a parametric Moebius transformation. A single parameter of control allows to describe, in a common framework, different types of decorations, by liquid triangles or 3-sided bubbles, and other non-conventional cells. A solution is proposed to explain the stability threshold in the flower problem.

cond-mat.soft↗