On the finite size behavior of quantum collective spin systems

We discuss the finite size behavior of the adiabatic Dicke model, describing the collective coupling of a set of N-two level atoms (qubits) to a faster (electromagnetic) oscillator mode. The energy eigen-states of this system are shown to be directly related to those of another widely studied collective spin model, the uniaxial one. By employing an approximate continuum approach, we obtain a complete characterization of the properties of the latter, which we then use to evaluate the scaling properties of various observables for the original Dicke model near its quantum phase transition.Comment: 8 pages, 4 figure

Entanglement sharing in E⊗ϵE\otimes\epsilon Jahn-Teller model in the presence of a magnetic field

We discuss the ground state entanglement of the $E\otimes\epsilon$ Jahn-Teller model in the presence of a strong transverse magnetic field as a function of the vibronic coupling strength. A complete characterization is given of the phenomenon of entanglement sharing in a system composed by a qubit coupled to two bosonic modes. Using the residual $I$-tangle, we find that three-partite entanglement is significantly present in the system in the parameter region near the bifurcation point of the corresponding classical model

Entanglement of a qubit coupled to a resonator in the adiabatic regime

We discuss the ground state entanglement of a bi-partite system, composed by a qubit strongly interacting with an oscillator mode, as a function of the coupling strenght, the transition frequency and the level asymmetry of the qubit. This is done in the adiabatic regime in which the time evolution of the qubit is much faster than the oscillator one. Within the adiabatic approximation, we obtain a complete characterization of the ground state properties of the system and of its entanglement content.Comment: 6 pages, 7 figure

Hierarchical psychophysiological pathways subtend perceptual asymmetries in Neglect

Stroke patients with left Hemispatial Neglect (LHN) show deficits in perceiving left contralesional stimuli with biased visuospatial perception towards the right hemifield. However, very little is known about the functional organization of the visuospatial perceptual neural network and how this can account for the profound reorganization of space representation in LHN. In the present work, we aimed at (1) identifying EEG measures that discriminate LHN patients against controls and (2) devise a causative neurophysiological model between the discriminative EEG measures. To these aims, EEG was recorded during exposure to lateralized visual stimuli which allowed for pre-and post-stimulus activity investigation across three groups: LHN patients, lesioned controls, and healthy individuals. Moreover, all participants performed a standard behavioral test assessing the perceptual asymmetry index in detecting lateralized stimuli. The between-groups discriminative EEG patterns were entered into a Structural Equation Model for the identification of causative hierarchical associations (i.e., pathways) between EEG measures and the perceptual asymmetry index. The model identified two pathways. A first pathway showed that the combined contribution of pre-stimulus frontoparietal connectivity and individual-alpha-frequency predicts post-stimulus processing, as measured by visual-evoked N100, which, in turn, predicts the perceptual asymmetry index. A second pathway directly links the inter-hemispheric distribution of alpha-amplitude with the perceptual asymmetry index. The two pathways can collectively explain 83.1% of the variance in the perceptual asymmetry index. Using causative modeling, the present study identified how psychophysiological correlates of visuospatial perception are organized and predict the degree of behavioral asymmetry in LHN patients and controls

Isolated office hypertension : A 3-year follow-up study

The study aimed to evaluate, over a 3-year period, the progression towards sustained hypertension and left ventricular (LV) changes in patients with isolated office (IO) hypertension (office BP140 and/or 90 mmHg, daytime BP130/80 mmHg). After 3 years from the basal evaluation, 38 subjects with basal normal BP and 42 subjects with basal IO hypertension underwent a second 24-h BP monitoring and echocardiography; 19 patients of the basal IO hypertension group were not revaluated because they had already developed ambulatory hypertension and were on antihypertensive treatment. At the second evaluation, the 38 normotensive subjects had unchanged BP and LV parameters; 25 IO hypertensives have developed sustained hypertension. Considering them together with the 19 patients already treated, 72% of 61 IO hypertensives developed ambulatory hypertension over a 3-year period. The patients who subsequently developed hypertension differed from the group who did not only for lower basal values of LV diastolic parameters; all the patients with basal LV hypertrophy and/or preclinical diastolic impairment subsequently developed sustained hypertension. In conclusion, IO hypertensive patients show a high rate of progression towards sustained hypertension. Basal LV hypertrophy and/or preclinical diastolic dysfunction were the only markers of a greater risk of becoming hypertensives

Care pathways models and clinical outcomes in disorders of consciousness

Objective: Patients with Disorders of consciousness, are persons with extremely low functioning levels and represent a challenge for health care systems due to their high needs of facilitating environmental factors. Despite a common Italian health care path-way for these patients, no studies have analyzed information on how each region have implemented it in its welfare system correlating data with patients’ clinical outcomes. Materials and Methods: A multicenter observational pilot study was realized. Clinicians collected data on the care pathways of patients with Disorder of consciousness by ask-ing 90 patients’ caregivers to complete an ad hoc questionnaire through a structured phone interview. Questionnaire consisted of three sections: sociodemographic data, description of the care pathway done by the patient, and caregiver evaluation of health services and information received.Results: Seventy- three patients were analyzed. Length of hospital stay was different across the health care models and it was associated with improvement in clinical diag-nosis. In long- term care units, the diagnosis at admission and the number of caregivers available for each patient (median value=3) showed an indirect relationship with worsening probability in clinical outcome. Caregivers reported that communication with professionals (42%) and the answer to the need of information were the most critical points in the acute phase, whereas presence of Non- Governmental Organizations (25%) and availability of psychologists for caregivers (21%) were often missing during long-term care. The 65% of caregivers reported they did not know the UN Convention on the Rights of Persons with Disabilities. Conclusion: This study highlights relevant differences in analyzed models, despite a recommended national pathway of care. Future public health considerations and ac-tions are needed to guarantee equity and standardization of the care process in all European countries

A Real-World, Multicenter, Observational Retrospective Study of Durvalumab After Concomitant or Sequential Chemoradiation for Unresectable Stage III Non-Small Cell Lung Cancer

Introduction: For unresectable stage III non-small cell lung cancer (NSCLC), the standard therapy consists of chemoradiotherapy (CRT) followed by durvalumab maintenance for responding patients. The present study reports on the safety and outcome of durvalumab use after CRT in a real-world, multicenter, retrospective cohort. Methods: Two hundred thirty-eight patients have been included. We collected data on systemic therapy, radiation therapy, the timing between CRT and durvalumab, number of durvalumab cycles, reasons for non-starting or discontinuation, incidence and grade of adverse events (AEs), and progression-free survival (PFS) and overall survival (OS). Results: One hundred fifty-five patients out of 238 (65.1%) received at least one durvalumab dose: 91 (58.7%) after concomitant CRT (cCRT) and 64 (41.3%) after sequential CRT (sCRT). Programmed-death ligand 1 (PD-L1) status was unknown in 7/155 (4.5%), negative in 14 (9.1%), and positive ≥1% in 134/155 (86.4%). The main reasons for non-starting durvalumab were progression (10.1%), PD-L1 negativity (7.5%), and lung toxicity (4.6%). Median follow-up time was 14 months (range 2–29); 1-year PFS and OS were 83.5% (95%CI: 77.6–89.7) and 97.2% (95%CI: 94.6–99.9), respectively. No significant differences in PFS or OS were detected for cCRT vs. sCRT, but the median PFS was 13.5 months for sCRT vs. 23 months for cCRT. Potentially immune-related AEs were recorded in 76/155 patients (49.0%). Pneumonitis was the most frequent, leading to discontinuation in 11/155 patients (7.1%). Conclusions: Durvalumab maintenenace after concurrent or sequential chemoradiation for unresectable, stage III NSCLC showed very promising short-term survival results in a large, multicenter, restrospective, real-world study. Durvalumab was the first drug obtaining a survival benefit over CRT within the past two decades, and the present study contributes to validating its use in clinical practice

Shedding light on X17: community report

The workshop “Shedding light on X17” brings together scientists looking for the existence of a possible new light particle, often referred to as X17. This hypothetical particle can explain the resonant structure observed at ∼ 17 MeV in the invariant mass of electron-positron pairs, produced after excitation of nuclei such as 8Be and 4He by means of proton beams at the Atomki Laboratory in Debrecen. The purpose of the workshop is to discuss implications of this anomaly, in particular theoretical interpretations as well as present and future experiments aiming at confirming the result and/or at providing experimental evidence for its interpretation

Viaggio nel mondo dei quanti. Le avventure di Alice nel paese delle meraviglie

Scuola "Archimede" in Scienze, Comunicazione e Tecnologie, Fisiche e Tecnologie Quantistiche Ciclo XXVI, a.a. 2014L’era digitale, internet e la multimedialità hanno notevolmente modificato il modo in cui ragazzi e adolescenti fruiscono le informazioni, rispetto alla precedente generazione. Abbiamo di fronte degli individui, i nativi digitali, che hanno accesso giornaliero ai social network, agli smartphone, alle app, tutti ricchi di contenuti multimediali che implicano una propensione verso le immagini, la lettura veloce e il multitasking. Sono cresciuti con una minore capacità di attenzione verso il testo scritto e un’attenzione più spiccata verso l’immagine. Tutto ciò deve far riflettere sulla necessità di creare nuovi modelli e contenuti per la divulgazione scientifica, che siano più appropriati e si adeguino al nuovo modo di approcciarsi e fruire le informazioni. Il presente progetto propone un prodotto multimediale che comprende il fumetto, il libro illustrato e il CD interattivo come mezzo alternativo di comunicazione e insegnamento della fisica quantistica agli adolescenti, essendo questi contenuti molto prossimi ai modelli comunicativi che risultano familiari agli adolescenti. Contenuto del progetto è una storia, con un personaggio molto noto, Alice del celebre romanzo di Lewis Carroll, Alice's Adventures in Wonderland, protagonista di un viaggio “alternativo” rispetto a quello che ‘storicamente’ ha fatto. Un viaggio in un mondo popolato da elettroni, fotoni e scienziati impegnati a spiegare gli strani principi della fisica quantistica, che sembrano curiosi almeno quanto quelli del paese delle meraviglie.Università della Calabri