meV resolution in laser-assisted energy-filtered transmission electron microscopy

The electronic, optical, and magnetic properties of quantum solids are determined by their low-energy (< 100 meV) many-body excitations. Dynamical characterization and manipulation of such excitations relies on tools that combine nm-spatial, fs-temporal, and meV-spectral resolution. Currently, phonons and collective plasmon resonances can be imaged in nanostructures with sub-nm and 10s meV space/energy resolution using state-of-the-art energy-filtered transmission electron microscopy (TEM), but only under static conditions, while fs-resolved measurements are common but lack spatial or energy resolution. Here, we demonstrate a new method of spectrally resolved photon-induced near-field electron microscopy (SRPINEM) that allows us to obtain nm-fs-resolved maps of nanoparticle plasmons with an energy resolution determined by the laser linewidth (20 meV in this work), and not limited by electron beam and spectrometer energy spreading. This technique can be extended to any optically-accessible low-energy mode, thus pushing TEM to a previously inaccessible spectral domain with an unprecedented combination of space, energy and temporal resolution.Comment: 19 pages, 7 figure

From attosecond to zeptosecond coherent control of free-electron wave functions using semi-infinite light fields

Light-electron interaction in empty space is the seminal ingredient for free-electron lasers and also for controlling electron beams to dynamically investigate materials and molecules. Pushing the coherent control of free electrons by light to unexplored timescales, below the attosecond, would enable unprecedented applications in light-assisted electron quantum circuits and diagnostics at extremely small timescales, such as those governing intramolecular electronic motion and nuclear phenomena. We experimentally demonstrate attosecond coherent manipulation of the electron wave function in a transmission electron microscope, and show that it can be pushed down to the zeptosecond regime with existing technology. We make a relativistic pulsed electron beam interact in free space with an appropriately synthesized semi-infinite light field generated by two femtosecond laser pulses reflected at the surface of a mirror and delayed by fractions of the optical cycle. The amplitude and phase of the resulting coherent oscillations of the electron states in energymomentum space are mapped via momentum-resolved ultrafast electron energy-loss spectroscopy. The experimental results are in full agreement with our theoretical framework for light-electron interaction, which predicts access to the zeptosecond timescale by combining semi-infinite X-ray fields with free electrons.Comment: 22 pages, 6 figure

AIOCJ: A Choreographic Framework for Safe Adaptive Distributed Applications

We present AIOCJ, a framework for programming distributed adaptive applications. Applications are programmed using AIOC, a choreographic language suited for expressing patterns of interaction from a global point of view. AIOC allows the programmer to specify which parts of the application can be adapted. Adaptation takes place at runtime by means of rules, which can change during the execution to tackle possibly unforeseen adaptation needs. AIOCJ relies on a solid theory that ensures applications to be deadlock-free by construction also after adaptation. We describe the architecture of AIOCJ, the design of the AIOC language, and an empirical validation of the framework.Comment: Technical Repor

Precise and ultrafast molecular sieving through graphene oxide membranes

There has been intense interest in filtration and separation properties of graphene-based materials that can have well-defined nanometer pores and exhibit low frictional water flow inside them. Here we investigate molecular permeation through graphene oxide laminates. They are vacuum-tight in the dry state but, if immersed in water, act as molecular sieves blocking all solutes with hydrated radii larger than 4.5A. Smaller ions permeate through the membranes with little impedance, many orders of magnitude faster than the diffusion mechanism can account for. We explain this behavior by a network of nanocapillaries that open up in the hydrated state and accept only species that fit in. The ultrafast separation of small salts is attributed to an 'ion sponge' effect that results in highly concentrated salt solutions inside graphene capillaries

Quantitative assessment of diffuse myocardial fibrosis in II-type diabetes mellitus patients using T1 mapping technique: preliminary data

In diabetic cardiomyopathy (DCM), ventricular remodelling consists in a progressive impairment of myocardial contraction (evolving from diastolic to combined diastolic-systolic dysfunction) occurring regardless of ischemic heart disease, hypertension or other macrovascular complications, which ultimately leads to heart failure. Early stages of DCM are asymptomatic and characterised by initial contractile disfunction and various degree of myocardial fibrosis, that may not be recognised by traditional cardiology tests. Our purpose was to detect myocardial fibrotic infiltration in DM-II patients by using T1-mapping technique with extracellular volume fraction (ECV) measurement

4D flow imaging of the thoracic aorta: is there an added clinical value?

Four-dimensional (4D) flow MRI has emerged as a powerful non-invasive technique in cardiovascular imaging, enabling to analyse in vivo complex flow dynamics models by quantifying flow parameters and derived features. Deep knowledge of aortic flow dynamics is fundamental to better understand how abnormal flow patterns may promote or worsen vascular diseases. In the perspective of an increasingly personalized and preventive medicine, growing interest is focused on identifying those quantitative functional features which are early predictive markers of pathological evolution. The thoracic aorta and its spectrum of diseases, as the first area of application and development of 4D flow MRI and supported by an extensive experimental validation, represents the ideal model to introduce this technique into daily clinical practice. The purpose of this review is to describe the impact of 4D flow MRI in the assessment of the thoracic aorta and its most common affecting diseases, providing an overview of the actual clinical applications and describing the potential role of derived advanced hemodynamic measures in tailoring follow-up and treatment

Laser-Induced Skyrmion Writing and Erasing in an Ultrafast Cryo-Lorentz Transmission Electron Microscopy

We demonstrate that light-induced heat pulses of different duration and energy can write skyrmions in a broad range of temperatures and magnetic field in FeGe. Using a combination of camera-rate and pump-probe cryo-Lorentz Transmission Electron Microscopy, we directly resolve the spatio-temporal evolution of the magnetization ensuing optical excitation. The skyrmion lattice was found to maintain its structural properties during the laser-induced demagnetization, and its recovery to the initial state happened in the sub-{\mu}s to {\mu}s range, depending on the cooling rate of the system

Well-Being of Lesbian, Gay, Bisexual Youth: The Influence of Rural and Urban Contexts on the Process of Building Identity and Disclosure

The study investigates how the territorial community can influence the individual and social well-being of lesbian, gay, bisexual (LGB) youth and especially the recognition of their feelings and the construction of their own identity as well as their needs to be socially recognized. This research focuses on the experiences of 30 LGB individuals (23 males and 7 females), with a mean age of 25.07 years (SD = 4,578), living in urban and rural areas of Southern Italy. Focalized open interviews were conducted, and the Grounded Theory Methodology, supported by the Atlas.ti 8.0 software, was used for data analysis. The textual material was first coded, and then codes were grouped into five macro-categories: Freedom of identity expression in the urban and rural context, identity construction and acceptance process, need of aggregation and identification with the LGB community, role of the interpersonal relationship in the process of identity acceptance, socio-cultural context, and LGB psychological well-being. The results showed a condition common to the two contexts that we can define as “ghettoization.” The young LGB is alone in the rural area due to a lack of places and people to identify with and greater social isolation. On the contrary, although there are more opportunities in the urban area, young people feel stigmatized and ghettoized because “their places” are frequented exclusively by the lesbian, gay, bisexual, transexual, queer (LGBTQ) community. The work will extensively discuss the limitations of the research, future proposals, and the practical implications of the results

Homogeneous Open Quantum Random Walks on a lattice

We study Open Quantum Random Walks for which the underlying graph is a lattice, and the generators of the walk are translation-invariant. We consider the quantum trajectory associated with the OQRW, which is described by a position process and a state process. We obtain a central limit theorem and a large deviation principle for the position process, and an ergodic result for the state process. We study in detail the case of homogeneous OQRWs on a lattice, with internal space $h={\mathbb C}^2$

Investigation of 76Se75Seand76Se75As{}^{76}Se{}^{75}Seand{}^{76}Se{}^{75}As transfer reactions at 15 MeV/u in a multi-channel approach within the NUMEN project

A full-comprehensive study of heavy-ion induced nuclear reac- tions is a powerful tool to characterize nuclear mean-field features as well as few- nucleon correlations in low-lying nuclear states. In this context, the investigation of 76Se(18O, 17O)75Se and 76Se(18O, 19F)75As transfer reactions was performed with the NUMEN project, aiming at providing data-driven information to constrain nu- clear structure models for the 76Se nucleus. This nucleus is under investigation since it is the daughter nucleus of 76Ge in the neutrinoless double beta decay (0νββ) pro- cess. The experiment was performed at INFN-LNS where the 18O beam impinged the 76Se target and the reaction ejectiles were momentum analyzed by the MAGNEX magnetic spectrometer