A hybrid classical-quantum approach to speed-up Q-learning.

We introduce a classical-quantum hybrid approach to computation, allowing for a quadratic performance improvement in the decision process of a learning agent. Using the paradigm of quantum accelerators, we introduce a routine that runs on a quantum computer, which allows for the encoding of probability distributions. This quantum routine is then employed, in a reinforcement learning set-up, to encode the distributions that drive action choices.

Entangled States Are Harder to Transfer than Product States.

The distribution of entangled states is a key task of utmost importance for many quantum information processing protocols. A commonly adopted setup for distributing quantum states envisages the creation of the state in one location, which is then sent to (possibly different) distant receivers through some quantum channels. While it is undoubted and, perhaps, intuitively expected that the distribution of entangled quantum states is less efficient than that of product states, a thorough quantification of this inefficiency (namely, of the difference between the quantum-state transfer fidelity for entangled and factorized states) has not been performed.

Exact Spectral Function of a Tonks-Girardeau Gas in a Lattice.

The single-particle spectral function of a strongly correlated system is an essential ingredient to describe its dynamics and transport properties. We develop a method to evaluate exactly the spectral function for a gas of one-dimensional bosons with infinitely strong repulsions valid for any type of external confinement. Focusing on the case of a lattice confinement, we find that the spectral function displays three main singularity lines.

Quantum Coherence and Ergotropy.

Constraints on work extraction are fundamental to our operational understanding of the thermodynamics of both classical and quantum systems. In the quantum setting, finite-time control operations typically generate coherence in the instantaneous energy eigenbasis of the dynamical system. Thermodynamic cycles can, in principle, be designed to extract work from this nonequilibrium resource.

Role of coherence in the nonequilibrium thermodynamics of quantum systems.

Exploiting the relative entropy of coherence, we isolate the coherent contribution in the energetics of a driven nonequilibrium quantum system. We prove that a division of the irreversible work can be made into a coherent and incoherent part. This provides an operational criterion for quantifying the coherent contribution in a generic nonequilibrium transformation on a closed quantum system.

Optimal Work Extraction and Thermodynamics of Quantum Measurements and Correlations.

We analyze the role of indirect quantum measurements in work extraction from quantum systems in nonequilibrium states. In particular, we focus on the work that can be obtained by exploiting the correlations shared between the system of interest and an additional ancilla, where measurement backaction introduces a nontrivial thermodynamic tradeoff. We present optimal state-dependent protocols for extracting work from both classical and quantum correlations, the latter being measured by discord.

Quantum Critical Scaling under Periodic Driving.

Universality is key to the theory of phase transitions, stating that the equilibrium properties of observables near a phase transition can be classified according to few critical exponents. These exponents rule an universal scaling behaviour that witnesses the irrelevance of the model's microscopic details at criticality. Here we discuss the persistence of such a scaling in a one-dimensional quantum Ising model under sinusoidal modulation in time of its transverse magnetic field.

Quantum Zeno-type effect and non-Markovianity in a three-level system.

We study the coexistence of the quantum Zeno-type effect and non-Markovianity for a system decaying in a structured bosonic environment and subject to a control field. The interaction with the environment induces decay from the excited to the ground level, which, in turn, is coherently coupled to another meta-stable state. The control of the strength of the coherent coupling between the stable levels allows the engineering of both the dissipation and of the memory effects, without modifying neither the system-reservoir interaction, nor environmental properties.

Statistics of work and orthogonality catastrophe in discrete level systems: an application to fullerene molecules and ultra-cold trapped Fermi gases.

The sudden introduction of a local impurity in a Fermi sea leads to an anomalous disturbance of its quantum state that represents a local quench, leaving the system out of equilibrium and giving rise to the Anderson orthogonality catastrophe. The statistics of the work done describe the energy fluctuations produced by the quench, providing an accurate and detailed insight into the fundamental physics of the process. We present here a numerical approach to the non-equilibrium work distribution, supported by applications to phenomena occurring at very diverse energy ranges.

Irreversible work and inner friction in quantum thermodynamic processes.

We discuss the thermodynamics of closed quantum systems driven out of equilibrium by a change in a control parameter and undergoing a unitary process. We compare the work actually done on the system with the one that would be performed along ideal adiabatic and isothermal transformations. The comparison with the latter leads to the introduction of irreversible work, while that with the former leads to the introduction of inner friction.

Orthogonality catastrophe and decoherence in a trapped-fermion environment.

The Fermi-edge singularity and the Anderson orthogonality catastrophe describe the universal physics which occurs when a Fermi sea is locally quenched by the sudden switching of a scattering potential, leading to a brutal disturbance of its ground state. We demonstrate that the effect can be seen in the controllable domain of ultracold trapped gases by providing an analytic description of the out-of-equilibrium response to an atomic impurity, both at zero and at finite temperature. Furthermore, we link the transient behavior of the gas to the decoherence of the impurity, and to the degree of the non-Markovian nature of its dynamics.

Core-hole effects in fullerene molecules and small-diameter conducting nanotubes: a density functional theory study.

Core-hole induced electron excitations in fullerene molecules, and small-diameter conducting carbon nanotubes, are studied using density functional theory with minimal, split-valence, and triply-split-valence basis sets plus the generalized gradient approximation by Perdew-Burke-Ernzerhof for exchange and correlation. Finite-size computations are performed on the carbon atoms of a C(60) Bucky ball and a piece of (3, 3) armchair cylindrical network, terminated by hydrogen atoms, while periodically boundary conditions are imposed on a (3, 3) nanotube unit cell. Sudden creation of the core state is simulated by replacing a 1s electron pair, localized at a central site of the structures, with the effective pseudo-potentials of both neutral and ionized atomic carbon.

Discording power of quantum evolutions.

We introduce the discording power of a unitary transformation, which assesses its capability to produce quantum discord, and analyze in detail the generation of discord by relevant classes of two-qubit gates. Our measure is based on the Cartan decomposition of two-qubit unitaries and on evaluating the maximum discord achievable by a unitary upon acting on classical-classical states at fixed purity. We find that there exist gates which are perfect discorders for any value of purity μ, and that they belong to a class of operators that includes the sqrt[SWAP].

Protecting entanglement via the quantum Zeno effect.

We study the exact entanglement dynamics of two atoms in a lossy resonator. Besides discussing the steady-state entanglement, we show that in the strong coupling regime the system-reservoir correlations induce entanglement revivals and oscillations and propose a strategy to fight against the deterioration of the entanglement using the quantum Zeno effect.

Local control of entanglement in a spin chain.

In a ferromagnetic spin chain, the control of the local effective magnetic field allows us to manipulate the static and dynamical properties of entanglement. In particular, the propagation of quantum correlations can be driven to a great extent so as to achieve an entanglement transfer on demand toward a selected site.

[Diagnosis of heart failure in general medicine: role of cerebral natriuretic peptide. Results of a pilot study of a population sample from Calabria].

Background: The aim of this study was to evaluate the usefulness of brain natriuretic peptide (BNP) in diagnosing congestive heart failure (CHF), in an unselected population.

Methods: Eighty-three patients (47 men, 36 women, mean age 70 +/- 10 years) were referred to our hospital ambulatory from their general practitioners, with a diagnosis of CHF.

Results: Clinical-instrumental evaluation confirmed diagnosis in 45 patients (54%) (group A), and excluded it in the remaining 38 (46%) (group B).

[Thrombolytic therapy during cardiopulmonary resuscitation for acute massive pulmonary embolism. A case report].

Massive pulmonary embolism associated with cardiac arrest has an extremely high mortality in spite of cardiopulmonary resuscitation maneuvers. An early diagnosis of pulmonary embolism as cause of cardiac arrest and a rapid specific therapy able to obtain a restoration of pulmonary flow can improve the prognosis. The authors report a case of cardiac arrest for massive pulmonary embolism promptly diagnosed by echocardiography and treated by thrombolytic therapy with an initial favourable outcome.

Shot noise for resonant Cooper pair tunneling.

We study intrinsic noise of current in a superconducting single-electron transistor, taking into account both coherence effects and Coulomb interaction near a Cooper pair resonance. Because of this interplay, the statistics of tunneling events deviates from the Poisson distribution and, more important, it shows even-odd asymmetry in the transmitted charge. The zero-frequency noise is suppressed significantly when the quasiparticle tunneling rates are comparable to the coherent oscillation frequency of Cooper pairs.

[Functional heart murmur and echocardiography: a solved problem?].

Background: Is it really vanished the need for echocardiography in the differential diagnosis of functional pediatric murmurs?

Methods: To this aim 260 children (132 males, 128 females; age range 1-84 months) were examined with auscultatory cardiac murmur. All children underwent a clinical and instrumental evaluation (ECG and echocardiography) from two pediatric cardiologists with independent assessment.

Results: Two hundred and ten patients (Group A) were evaluated clinically with functional murmur, 45 patients (Group B) with pathological murmur, 5 patients (Group C) with uncertain pathology.

[The usefulness of the association of clinical probability, rapid plasma measurement of D-dimer, compression echography of the lower limbs and echocardiography in the diagnosis of acute pulmonary embolism].

Background: The aim of this study was to investigate the diagnostic utility of clinical probability, rapid plasma D-dimer assay, compression ultrasonography (CUS) and transthoracic echocardiography (TTE) in patients with suspected pulmonary embolism.

Methods: One hundred forty consecutive outpatients with suspected pulmonary embolism were enrolled in a prospective trial. We evaluated sensitivity, specificity, positive and negative predictive value of a combination of clinical probability, D-dimer, CUS and TTE using perfusion lung scan and pulmonary angiography as a combined gold standard for determining the presence or absence of pulmonary embolism.

[A health education program for the prevention of heart diseases carried out in a population in Calabria].

Background: To evaluate the behaviour and knowledge of students on cardiovascular risk factors and to programme a campaign for the prevention of cardiovascular diseases.

Methods: All students attending the last year of the secondary school of this province answered a questionnaire. An educational campaign followed the analysis of the questionnaire.

Successful treatment of right heart thromboemboli with IV recombinant tissue-type plasminogen activator during continuous echocardiographic monitoring: a case series report.

Background And Study Objective: Echocardiographic detection of right heart thromboemboli (RHTE) during pulmonary embolism (PE) shows an uncommon but life-threatening event. The treatment of this condition is not well established. The aim of our study is to evaluate the efficacy and safety of recombinant tissue-type plasminogen activator (rt-PA) in treating RHTE.

[Results of a survey on knowledge and habits among hospital doctors concerning primary prevention of venous thromboembolism].

Background: The purpose of this study was to analyse the attitudes towards and knowledge of primary prevention of venous thromboembolism (VTE) among hospital doctors in Calabria.

Methods: The survey was based on theoretical knowledge and practical management of hortopedics, surgeons, gynecologists and internists working in 14 hospitals.

Results: Out of a total of 340 physicians contacted, 154 (45%) agreed to take part in the survey.

[The prevalence and clinical characteristics of heart failure in a population sample of Calabria].

Two-hundred and fourteen patients with congestive heart failure were identified over a six-month period in the general practice of 29 GPs covering an adult population of 29,959 subjects residing in the region of Calabria, in southern Italy, with an overall prevalence of 7 per 1000. Males represented 52% of the cases and females 48%, with a median age of 75 years. On average, the condition was first diagnosed 41 months before the present examination.

New introducer technique for implanting pacemakers and defibrillator leads: percutaneous incannulation of the cephalic vein.

Objectives: This study was designed to assess the feasibility of percutaneous incannulation of cephalic vein for the implantation of pacemaker and defibrillator leads.

Background: The development of the subclavian vein puncture technique for pacemaker lead implantation has many advantages compared to surgical isolation of cephalic vein. However, initial enthusiasm has been dampened by reports of serious complications because of the anatomical relationships of the subclavian vein.