1,206 research outputs found
Vortex entanglement in Bose-Einstein condensates coupled to Laguerre-Gauss beams
We study the establishment of vortex entanglement in remote and weakly
interacting Bose Einstein condensates. We consider a two-mode photonic resource
entangled in its orbital angular momentum (OAM) degree of freedom and, by
exploiting the process of light-to-BEC OAM transfer, demonstrate that such
entanglement can be efficiently passed to the matter-like systems. Our proposal
thus represents a building block for novel low-dissipation and long-memory
communication channels based on OAM. We discuss issues of practical
realizability, stressing the feasibility of our scheme and present an operative
technique for the indirect inference of the set vortex entanglement.Comment: 10 pages, 7 figures, RevTex
Orthogonality catastrophe as a consequence of qubit embedding in an ultra-cold Fermi gas
We investigate the behaviour of a single qubit coupled to a low-dimensional,
ultra-cold Fermi gas. The scattering between the system and the fermions leads
to the loss of any coherence in the initial state of the qubit and we show that
the exact dynamics of this process is strongly influenced by the effect of the
orthogonality catastrophe within the gas. We highlight the relationship between
the Loschmidt echo and the retarded Green's function - typically used to
formulate the dynamical theory of the catastrophe - and demonstrate that the
effect can be triggered and characterized via local operations on the qubit. We
demonstrate how the expected broadening of the spectral function can be
observed using Ramsey interferometry on the qubit.Comment: 4 and a bit pages, 3 figures. Updated versio
ALGORITMO PER LA VALUTAZIONE OGGETTIVA DELLE BUONE PRASSI
Il lavoro su cui qui si riferisce ha tratto spunto dall’iniziativa – supportata da Inail Piemonte – del concorso “meno carta più sicurezza”, un concorso nato per valorizzare le buone prassi vantaggiose anche in termini di gestione economica dei rischi ed estendibilità a situazioni assimilabili.
Sin dalle prime fasi di attività della giuria, ci si è resi conto della mancanza di metodiche formalizzate di valutazione, essendo la maggior parte dei criteri adottati a livello nazionale ed europeo, basati su un approccio qualitativo, non esente da valutazioni soggettive.
Inail Piemonte e Politecnico di Torino hanno, quindi, ritenuto utile impostare un metodo formalizzato per: a) individuare un criterio di organizzazione dei dati di ingresso, b) identificare nei progetti parametri valutabili, oggettivi e numericamente quantificabili, c) sviluppare un algoritmo di elaborazione dei valori di detti parametri, per una valutazione motivata delle proposte.
Detto metodo è stato testato su una serie di casi reali tratti dal citato concorso e sviluppato in forma di tecnica computer assistita
Oxidative fermentation of glucose and ethanol in designed media and cooked grape must by acetic acid bacteria
In this study, acetic acid bacteria strains were investigated for their ability to oxidize different carbon sources producing the corresponding oxidative products. Bacterial strains were cultivated in seven designed media and their acetification ability was assessed. The most performing strains were further tested to evaluate gluconic acid production in cooked grape must. Organic acids, sugars, and ethanol concentrations were assayed by high-pressure liquid chromatography. Overall, the findings showed high variability amongst strains of the same species, especially amongst Gluconobacter oxydans strains. However, strains ATCC 621H and DSM 3503T resulted to be the highest gluconic acid producers in all tested conditions. This study shows that grape must can be further valorized by selective fermentations for the production of gluconic based products
Advances in Food, Bioproducts and Natural Byproducts for a Sustainable Future: From Conventional to Innovative Processes
The world population is expected to reach almost 10,000 million in 2050, which entails the need to focus on sustainability and its three pillars: the economy, the environment, and society. Within this context, it is necessary to use our resources efficiently; for instance, we will need to produce much more food using less land and while polluting less to optimize the production of biomass from diversified resources, along with its subsequent conversion, fractionation, and processing. To achieve this, new approaches and processes, with special emphasis from a biotechnological perspective, may need to be implemented to move towards a circular model that will confer environmental sustainability. Global projections of food losses constitute an abundant pool of complex carbohydrates, proteins, lipids, and functional compounds. Hence, the deployment of food waste streams as raw materials will encompass the formulation of added-value products that will be ideally reintroduced in the food supply chain to close the loop.
Therefore, the analysis and optimization of any food and bioproduct process, as well as the development of innovative and emerging food and by-product processing methods, are important as a necessity for the sustainable transition to a bioeconomy era. The valorization, bioprocessing, and biorefining of food-industry-based streams, the role of industrial microorganisms, the isolation of high-added-value compounds, applications of the resulting bio-based chemicals in food manufacturing, novel food formulations, economic policies for food waste management, along with sustainability or techno-economic assessment of processing methods constitute subject areas that need to be addressed. More specifically, bioprocess design to valorize food-industry waste and by-product streams should be initiated by characterizing the composition of the onset raw material with the aim of identifying the target end-products, whereas the generation of multiple high-added-value products is a prerequisite for cost-effective processes to establish economic sustainability. On top of that, the feasibility of innovative processes could be sustained by encompassing food applications, driven by the constantly emerging consumers’ demand for functional foods and beverages with enhanced nutritional value. Equally, a growing awareness for bio-based and natural food components is being developed, thereby imposing challenges on the substitution of chemically derived ingredients with their natural counterparts
Advances in Food, Bioproducts and Natural Byproducts for a Sustainable Future: From Conventional to Innovative Processes
Probing mechanical quantum coherence with an ultracold-atom probe
We propose a scheme to probe quantum coherence in the state of a
nano-cantilever based on its magnetic coupling (mediated by a magnetic tip)
with a spinor Bose Einstein condensate (BEC). By mapping the BEC into a rotor,
its coupling with the cantilever results in a gyroscopic motion whose
properties depend on the state of the cantilever: the dynamics of one of the
components of the rotor angular momentum turns out to be strictly related to
the presence of quantum coherence in the state of the cantilever. We also
suggest a detection scheme relying on Faraday rotation, which produces only a
very small back-action on the BEC and it is thus suitable for a continuous
detection of the cantilever's dynamics.Comment: 7 pages, 4 figure
Critical assessment of two-qubit post-Markovian master equations
A post-Markovian master equation has been recently proposed as a tool to
describe the evolution of a system coupled to a memory-keeping environment [A.
Shabani and D. A. Lidar, Phys. Rev. A 71, 020101 (R) (2005)]. For a single
qubit affected by appropriately chosen environmental conditions, the
corresponding dynamics is always legitimate and physical. Here we extend such
situation to the case of two qubits, only one of which experiences the
environmental effects. We show how, despite the innocence of such an extension,
the introduction of the second qubit should be done cum grano salis to avoid
consequences such as the breaking of the positivity of the associated dynamical
map. This hints at the necessity of using care when adopting phenomenologically
derived models for evolutions occurring outside the Markovian framework.Comment: 7 pages, 1 figure, RevTeX4. Close to published versio
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