Economical Phase-Covariant Cloning of Qudits

We derive the optimal N to M phase-covariant quantum cloning for equatorial states in dimension d with M=kd+N, k integer. The cloning maps are optimal for both global and single-qudit fidelity. The map is achieved by an ``economical'' cloning machine, which works without ancilla.Comment: 10 pages revtex4, 7 figures, replaced with modified versio

Equilibration and nonclassicality of a double-well potential

A double well loaded with bosonic atoms represents an ideal candidate to simulate some of the most interesting aspects in the phenomenology of thermalisation and equilibration. Here we report an exhaustive analysis of the dynamics and steady state properties of such a system locally in contact with different temperature reservoirs. We show that thermalisation only occurs 'accidentally'. We further examine the nonclassical features and energy fluxes implied by the dynamics of the double-well system, thus exploring its finite-time thermodynamics in relation to the settlement of nonclassical correlations between the wells.Comment: 10 pages, 7 figures, Close to published versio

The antecedents of e-learning adoption within Italian corporate universities: A comparative case study

The implementation of Information and Communication Technologies (ICT) in business education appears to be influenced by a number of organizational issues, such as culture and technological sophistication. However, extant research has had very little to say about the antecedents that shape the adoption and diffusion of ICT across companies. In order to shed light on the phenomenon under investigation, this paper presents a comparative case study between five Italian companies that have instituted a corporate university. By distinguishing companies in typical cases and deviant cases with regard to the extensive use of e-learning technologies, our findings provide some useful insights about the antecedents that make companies more or less prone to employ the new frontiers of technology in their CUs

Global and local thermometry schemes in coupled quantum systems

We study the ultimate bounds on the estimation of temperature for an interacting quantum system. We consider two coupled bosonic modes that are assumed to be thermal and using quantum estimation theory establish the role the Hamiltonian parameters play in thermometry. We show that in the case of a conserved particle number the interaction between the modes leads to a decrease in the overall sensitivity to temperature, while interestingly, if particle exchange is allowed with the thermal bath the converse is true. We explain this dichotomy by examining the energy spectra. Finally, we devise experimentally implementable thermometry schemes that rely only on locally accessible information from the total system, showing that almost Heisenberg limited precision can still be achieved, and we address the (im)possibility for multiparameter estimation in the system.Comment: 16 pages, 5 figures. Close to published versio

A self-contained quantum harmonic engine

We propose a system made of three quantum harmonic oscillators as a compact quantum engine for producing mechanical work. The three oscillators play respectively the role of the hot bath, the working medium and the cold bath. The working medium performs an Otto cycle during which its frequency is changed and it is sequentially coupled to each of the two other oscillators. As the two environments are finite, the lifetime of the machine is finite and after a number of cycles it stops working and needs to be reset. We analyse the entanglement and quantum discord generated during the strokes and show that high work generation is always accompanied by large quantum correlations.Comment: Updated, published version. See also related but independent work from Pozas-Kerstjens et al. arXiv:1708.0636

Un secolo di ricerca scientifica sui porti antichi del Mediterraneo: Origini, sviluppi e prospettive

Harbours are constantly changing: their appearance is changing (due to the different processes that affect the shoreline) and there is a continuous turnover of people within them (merchants, travellers, harbour workers, etc). This dynamism can partially justify why scholars became interested in the historical and archaeological study of harbour areas only in recent times. Actually, it is thanks to the methodological and theoretical advances made in the last century that this field of study has known a significant development. This contribution aims at reconstructing the historiography of ancient harbours, identifying its key-moments; it will seek to understand how epistemological and practical breakthroughs made possible for harbour studies to achieve their own intellectual maturity.I porti sono ambienti altamente instabili: instabile è il contesto in cui si trovano (interfaccia tra terra e acqua); instabile è il contingente umano che li frequenta. Questa mutevolezza ne ha a lungo condizionato, se non addirittura ostacolato, lo studio. Tuttavia, le conquiste scientifiche dell’ultimo secolo, compiute tanto in ambito metodologico quanto concettuale, hanno permesso notevoli passi in avanti nella conoscenza degli ambienti portuali antichi. Obiettivo di questo contributo è quello di ripercorrere la storia degli studi sui porti antichi e identificarne i momenti chiave; in particolare, si tenterà di capire in che modo gli sviluppi epistemologici e pratici della scienza abbiano consentito a questo campo di studi di raggiungere la maturità intellettuale.I porti sono ambienti altamente instabili: instabile è il contesto in cui si trovano (interfaccia tra terra e acqua); instabile è il contingente umano che li frequenta. Questa mutevolezza ne ha a lungo condizionato, se non addirittura ostacolato, lo studio. Tuttavia, le conquiste scientifiche dell’ultimo secolo, compiute tanto in ambito metodologico quanto concettuale, hanno permesso notevoli passi in avanti nella conoscenza degli ambienti portuali antichi. Obiettivo di questo contributo è quello di ripercorrere la storia degli studi sui porti antichi e identificarne i momenti chiave; in particolare, si tenterà di capire in che modo gli sviluppi epistemologici e pratici della scienza abbiano consentito a questo campo di studi di raggiungere la maturità intellettuale

Ferromagnetic Ligand Holes in Cobalt Perovskite Electrocatalysts as Essential Factor for High Activity Towards Oxygen Evolution

The definition of the interplay between chemical composition, electro-magnetic configuration and catalytic activity requires a rational study of the orbital physics behind active materials. Apart from Coulomb forces, quantum spin exchange interactions (QSEI) are part of the potentials that differentiate the activity of magnetic oxides, strongly correlated electrocatalysts, in electron transfer reactions. Ferromagnetic (FM) cobalt oxides can show low overpotentials for the oxygen evolution reaction (OER) and the La1XSrXCoO3d (0 r X r 1) family of perovskites is good ground to gain understanding of the electronic interactions in strongly correlated catalysts. In this case, Sr-doping raises the OER activity and the conductivity and increases FM spin moments. The efficiency of electrocatalysts based on Earth-abundant 3d-transition metals correlates with the interrelated factors: mild-bonding energies, the reduction of the electronic repulsions because of the QSEI in the open-shells, and enhanced spin delocalization in FM ordering. The reason for the outstanding OER activity of SrCoO3d is the accumulation of FM holes in the 3d–2p bonds, including the ligand orbitals, thus facilitating spinselected charge transport and production of triplet O2 moieties from the oxidation of diamagnetic precursors. Spin-polarized oxygen atoms in the lattice can participate in O–O coupling and release of O2 in a Mars–Van Krevelen mechanistic fashion. We show that the stabilizing FM QSEI decrease the adsorption and activation energies during oxygen evolution and spin-dependent potentials are one of the factors that govern the catalytic activity of magnetic compositions: spintro-catalysis

Report on European Monetary Union

european union, financial markets, fiscal policy competition

Probing quantum features of photosynthetic organisms

Recent experiments have demonstrated strong coupling between living bacteria and light. Here we propose a scheme capable of revealing non-classical features of the bacteria (quantum discord of light-bacteria correlations) without exact modelling of the organisms and their interactions with external world. The scheme puts the bacteria in a role of mediators of quantum entanglement between otherwise non-interacting probing light modes. We then propose a plausible model of this experiment, using recently achieved parameters, demonstrating the feasibility of the scheme. Within this model we find that the steady state entanglement between the probes, which does not depend on the initial conditions, is accompanied by entanglement between the probes and bacteria, and provides independent evidence of the strong coupling between them.Comment: 9 pages, 3 figure