Effect of temperature on non-Markovian dynamics in Coulomb crystals

In this paper we generalize the results reported in Phys. Rev. A 88, 010101 (2013) and investigate the flow of information induced in a Coulomb crystal in presence of thermal noise. For several temperatures we calculate the non-Markovian character of Ramsey interferometry of a single 1/2 spin with the motional degrees of freedom of the whole chain. These results give a more realistic picture of the interplay between temperature, non-Markovianity and criticality.Comment: 5 pages, 3 figures. Accepted for publication in Special Issue of the International Journal of Quantum Information devoted to IQIS2013 conferenc

Simulation of open quantum dynamics and investigation of quantum correlations in finite systems

This thesis reports a series of theoretical studies regarding the dynamics of fewbody controllable quantum systems. Generally speaking, the main focus is on the behavior of correlations in open quantum systems and how these could be used both for applications to quantum technologies and investigations of more fundamental phenomena. The general physical setting for most of the results presented is trappedion systems. These have been proven to be an almost prefect practical platform for realizing a quantum computer. Furthermore, thanks to their exceptional degree of controllability, trapped ions have been lately employed to also simulate basic physics, ranging from condensed-matter to high-energy physics. Although the ndings in this manuscript are theoretical, real experimental parameters have been taken into account in order to provide a more realistic modeling. To this aim, a mixed of analytical and numerical methods have been extensively utilized. Concluding, we do believe that the theory developed in this thesis could be experimentally tested to give a more insightful view on open quantum system dynamics, both from a foundational and applicative point of view

Stationary entanglement in N-atom subradiant degenerate cascade systems

We address ultracold $N$-atom degenerate cascade systems and show that stationary subradiant states, already observed in the semiclassical regime, also exist in a fully quantum regime and for a small number of atoms. We explicitly evaluate the amount of stationary entanglement for the two-atom configuration and show full inseparability for the three-atom case. We also show that a continuous variable description of the systems is not suitable to detect entanglement due to the nonGaussianity of subradiant states.Comment: 4 figure

Witnessing entanglement in hybrid systems

We extend the definition of entanglement witnesses based on structure factors to the case in which the position of the scatterers is quantized. This allows us to study entanglement detection in hybrid systems. We provide several examples that show how these extra degrees of freedom affect the detection of entanglement by directly contributing to the measurement statistics. We specialize the proposed witness operators for a chain of trapped ions. Within this framework, we show how the collective vibronic state of the chain can act as an undesired quantum environment and how ions quantum motion can affect the entanglement detection. Finally, we investigate some specific cases where the method proposed leads to detection of hybrid entanglement.Comment: 6 pages, 4 figure

A simple trapped-ion architecture for high-fidelity Toffoli gates

We discuss a simple architecture for a quantum Toffoli gate implemented using three trapped ions. The gate, which in principle can be implemented with a single laser-induced operation, is effective under rather general conditions and is strikingly robust (within any experimentally realistic range of values) against dephasing, heating and random fluctuations of the Hamiltonian parameters. We provide a full characterization of the unitary and noise-affected gate using three-qubit quantum process tomography

Computational analysis of cooling dynamics in photonic-crystal-based thermal switches

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Between Participatory Approaches and Politics, Promoting Social Innovation in Smart Cities: Building a Hum–Animal Smart City in Lucca

In recent decades, the interest in social innovation and nature-based solutions has spread in scientific articles, and they are increasingly deployed for cities’ strategic planning. In this scenario, participatory approaches become pivotal to engaging the population and stakeholders in the decision- making process. In this paper, we reflect on the first year’s results and the strengths and weaknesses— of the participatory activities realized in Lucca to co-design and co-deploy a smart city based on human–animal relationships in the framework of the European project Horizon 2020 (IN-HABIT). Human–animal bonds, as nature-based solutions, are scientifically and practically underestimated. Data were collected on the activities organized to implement a public–private–people partnership in co-designing infrastructural solutions (so-called Animal Lines) and soft nature-based solutions to be implemented in the city. Stakeholders actively engaged in mutual discussions with great enthusiasm, and the emergent ideas (the need to improve people’s knowledge of animals and develop a map showing pet-friendly services and places and the need for integration to create innovative pet services) were copious and different while showing many connections among the various points of view. At the same time, a deeper reflection on the relationships among the participatory activities and institutionally integrated arrangements also emerged