Nonergodic behavior of the clean Bose-Hubbard chain

We study ergodicity breaking in the clean Bose-Hubbard chain for small hopping strength. We see the existence of a non-ergodic regime by means of indicators as the half-chain entanglement entropy of the eigenstates, the average level spacing ratio, {the properties of the eigenstate-expectation distribution of the correlation and the scaling of the Inverse Participation Ratio averages.} We find that this ergodicity breaking {is different from many-body localization} because the average half-chain entanglement entropy of the eigenstates obeys volume law. This ergodicity breaking appears unrelated to the spectrum being organized in quasidegenerate multiplets at small hopping and finite system sizes, so in principle it can survive also for larger system sizes. We find that some imbalance oscillations in time which could mark the existence of a glassy behaviour in space are well described by the dynamics of a single symmetry-breaking doublet and {quantitatively} captured by a perturbative effective XXZ model. We show that the amplitude of these oscillations vanishes in the large-size limit. {Our findings are numerically obtained for systems with $L < 12$. Extrapolations of our scalings to larger system sizes should be taken with care, as discussed in the paper.Comment: 18 pages, 13 figures, extensively revised version published in Physical Review B, Eq. (21) in the correct for

Antioxidant Supplementation in the Treatment of Aging-Associated Diseases

Oxidative stress is generally considered as the consequence of an imbalance between pro- and antioxidants species, which often results into indiscriminate and global damage at the organismal level. Elderly people are more susceptible to oxidative stress and this depends, almost in part, from a decreased performance of their endogenous antioxidant system. As many studies reported an inverse correlation between systemic levels of antioxidants and several diseases, primarily cardiovascular diseases, but also diabetes and neurological disorders, antioxidant supplementation has been foreseen as an effective preventive and therapeutic intervention for aging-associated pathologies. However, the expectations of this therapeutic approach have often been partially disappointed by clinical trials. The interplay of both endogenous and exogenous antioxidants with the systemic redox system is very complex and represents an issue that is still under debate. In this review a selection of recent clinical studies concerning antioxidants supplementation and the evaluation of their influence in aging-related diseases is analyzed. The controversial outcomes of antioxidants supplementation therapies, which might partially depend from an underestimation of the patient specific metabolic demand and genetic background, are presented

Entanglement entropy in a periodically driven Ising chain

In this work we study the entanglement entropy of a uniform quantum Ising chain in transverse field undergoing a periodic driving of period \u3c4. By means of Floquet theory we show that, for any subchain, the entanglement entropy tends asymptotically to a value \u3c4-periodic in time. We provide a semi-analytical formula for the leading term of this asymptotic regime: It is constant in time and obeys a volume law. The entropy in the asymptotic regime is always smaller than the thermal one: because of integrability the system locally relaxes to a generalized Gibbs ensemble (GGE) density matrix. The leading term of the asymptotic entanglement entropy is completely determined by this GGE density matrix. Remarkably, the asymptotic entropy shows marked features in correspondence to some non-equilibrium quantum phase transitions undergone by a Floquet state analog of the ground state

Adrenoreceptors and nitric oxide in the cardiovascular system

Nitric Oxide (NO) is a small molecule that continues to attract much attention from the scientific community. Since its discovery, it has been evident that NO has a crucial role in the modulation of vascular tone. Moreover, NO is involved in multiple signal transduction pathways thus contributing to the regulation of many cellular functions. NO effects can be either dependent or independent on cGMP, and rely also upon several mechanisms such as the amount of NO, the compartmentalization of the enzymes responsible for its biosynthesis (NOS), and the local redox conditions. Several evidences highlighted the correlation among adrenoreceptors activity, vascular redox status and NO bioavailability. It was suggested a possible crosstalk between NO and oxidative stress hallmarks in the endothelium function and adaptation, and in sympathetic vasoconstriction control. Adrenergic vasoconstriction is a balance between a direct vasoconstrictive effect on smooth muscle and an indirect vasorelaxant action caused by α2- and β-adrenergic endothelial receptor-triggered NO release. An increased oxidative stress and a reduction of NO bioavailability shifts this equilibrium causing the enhanced vascular adrenergic responsiveness observed in hypertension. The activity of NOS contributes to manage the adrenergic pathway, thus supporting the idea that the endothelium might control or facilitate β-adrenergic effects on the vessels and the polymorphic variants in β2-receptors and NOS isoforms could influence aging, some pathological conditions and individual responses to drugs. This seems to be dependent, almost in part, on differences in the control of vascular tone exerted by NO. Given its involvement in such important mechanisms, the NO pathway is implicated in aging process and in both cardiovascular and non-cardiovascular conditions. Thus, it is essential to pinpoint NO involvement in the regulation of vascular tone for the effective clinical/therapeutic management of cardiovascular diseases (CVD). © 2013 Conti, Russomanno, Corbi, Izzo, Vecchione and Filippelli

Adiabatic perturbation theory and geometry of periodically-driven systems

We give a systematic review of the adiabatic theorem and the leading non-adiabatic corrections in periodically-driven (Floquet) systems. These corrections have a two-fold origin: (i) conventional ones originating from the gradually changing Floquet Hamiltonian and (ii) corrections originating from changing the micro-motion operator. These corrections conspire to give a Hall-type linear response for non-stroboscopic (time-averaged) observables allowing one to measure the Berry curvature and the Chern number related to the Floquet Hamiltonian, thus extending these concepts to periodically-driven many-body systems. The non-zero Floquet Chern number allows one to realize a Thouless energy pump, where one can adiabatically add energy to the system in discrete units of the driving frequency. We discuss the validity of Floquet Adiabatic Perturbation Theory (FAPT) using five different models covering linear and non-linear few and many-particle systems. We argue that in interacting systems, even in the stable high-frequency regimes, FAPT breaks down at ultra slow ramp rates due to avoided crossings of photon resonances, not captured by the inverse-frequency expansion, leading to a counter-intuitive stronger heating at slower ramp rates. Nevertheless, large windows in the ramp rate are shown to exist for which the physics of interacting driven systems is well captured by FAPT.The authors would like to thank M. Aidelsburger, M. Atala, E. Dalla Torre, N. Goldman, M. Heyl, D. Huse, G. Jotzu, C. Kennedy, M. Lohse, T. Mori, L. Pollet, M. Rudner, A. Russomanno, and C. Schweizer for fruitful discussions. This work was supported by AFOSR FA9550-16-1-0334, NSF DMR-1506340, ARO W911NF1410540, and the Hungarian research grant OTKA Nos. K101244, K105149. M. K. was supported by Laboratory Directed Research and Development (LDRD) funding from Berkeley Lab, provided by the Director, Office of Science, of the U.S. Department of Energy under Contract No. DE-AC02-05CH11231. The authors are pleased to acknowledge that the computational work reported in this paper was performed on the Shared Computing Cluster which is administered by Boston University's Research Computing Services. The authors also acknowledge the Research Computing Services group for providing consulting support which has contributed to the results reported within this paper. The study of the driven non-integrable transverse-field Ising model was carried out using QuSpin [185] - an open-source state-of-the-art Python package for dynamics and exact diagonalization of quantum many body systems, available to download here. (FA9550-16-1-0334 - AFOSR; DMR-1506340 - NSF; W911NF1410540 - ARO; K101244 - Hungarian research grant OTKA; K105149 - Hungarian research grant OTKA; DE-AC02-05CH11231 - Laboratory Directed Research and Development (LDRD) funding from Berkeley Lab)https://arxiv.org/pdf/1606.02229.pd

Boundary time crystals

This work was supported in part by \Progetti Interni - Scuola Normale Superiore" (A.R.), EU- 691 QUIC (R.F. and A.R.), CRF Singapore Ministry of Education (CPR-QSYNC 692) (R.F.), EPSRC program TOPNES (EP/I031014/1) (J.K.).In this work we introduce boundary time crystals. Here continuous time-translation symmetry breaking occurs only in a macroscopic fraction of a many-body quantum system. After introducing their definition and properties, we analyze in detail a solvable model where an accurate scaling analysis can be performed. The existence of the boundary time crystals is intimately connected to the emergence of a time-periodic steady state in the thermodynamic limit of a many-body open quantum system. We also discuss connections to quantum synchronization.PostprintPeer reviewe

Many-Body Synchronization in a Classical Hamiltonian System

We study synchronization between periodically driven, interacting classical spins undergoing a Hamiltonian dynamics. In the thermodynamic limit there is a transition between a regime where all the spins oscillate synchronously for an infinite time with a period twice the driving period (synchronized regime) and a regime where the oscillations die after a finite transient (chaotic regime). We emphasize the peculiarity of our result, having been synchronization observed so far only in driven-dissipative systems. We discuss how our findings can be interpreted as a period-doubling time crystal and we show that synchronization can appear both for an overall regular and overall chaotic dynamics

The anti-ageing molecule sirt1 mediates beneficial effects of cardiac rehabilitation

Background An exercise-based Cardiac Rehabilitation Programme (CRP) is established as adjuvant therapy in heart failure (HF), nevertheless it is underutilized, especially in the elderly. While the functional and hemodynamic effects of CRP are well known, its underlying molecular mechanisms have not been fully clarified. The present study aims to evaluate the effects of a well-structured 4-week CRP in patients with stable HF from a molecular point of view. Results A prospective longitudinal observational study was conducted on patients consecutively admitted to cardiac rehabilitation. In fifty elderly HF patients with preserved ejection fraction (HFpEF), levels of sirtuin 1 (Sirt1) in peripheral blood mononuclear cells (PBMCs) and of its targets, the antioxidants catalase (Cat) and superoxide dismutase (SOD) in serum were measured before (Patients, P) and at the end of the CRP (Rehabilitated Patients, RP), showing a rise of their activities after rehabilitation. Endothelial cells (ECs) were conditioned with serum from P and RP, and oxidative stress was induced using hydrogen peroxide. An increase of Sirt1 and Cat activity was detected in RP-conditioned ECs in both the absence and presence of oxidative stress, together with a decrease of senescence, an effect not observed during Sirt1 and Cat inhibition. Conclusions In addition to the improvement in functional and hemodynamic parameters, a supervised exercise-based CRP increases Sirt1 activity and stimulates a systemic antioxidant defence in elderly HFpEF patients. Moreover, CRP produces antioxidant and anti-senescent effects in human endothelial cells mediated, at least in part, by Sirt1 and its target Cat

Knowledge and health care resource allocation: CME/CPD course guidelines-based efficacy.

BACKGROUND: Most health care systems consider continuing medical education a potential tool to improve quality of care and reduce disease management costs. Its efficacy in general practitioners needs to be further explored. OBJECTIVE: This study assesses the effectiveness of a one-year continuing medical education/continuing professional development course for general practitioners, regarding the improvement in knowledge of ARIA and GINA guidelines and compliance with them in asthma management. METHODS: Sixty general practitioners, covering 68,146 inhabitants, were randomly allocated to continuing medical education/continuing professional development (five residential events +four short distance-learning refresher courses over one year) or no training. Participants completed a questionnaire after each continuing medical education event; key questions were repeated at least twice. The Local Health Unit prescription database was used to verify prescription habits (diagnostic investigations and pharmacological therapy) and hospitalizations over one year before and after training. RESULTS: Fourteen general practitioners (46.7%) reached the cut-off of 50% attendance of the training courses. Knowledge improved significantly after training (p < 0.001, correct answers to key questions +13%). Training resulted in pharmaceutical cost containment (trained general practitioners +0.5% vs. controls +18.8%) and greater attention to diagnosis and monitoring (increase in spirometry +63.4%, p < 0.01). CONCLUSION: This study revealed an encouraging impact of educational events on improvement in general practitioner knowledge of guidelines and daily practice behavioral changes. Long-term studies of large populations are required to assess the effectiveness of education on the behavior of physicians in asthma management, and to establish the best format for educational events