Stochastic Variational Approach to Minimum Uncertainty States

We introduce a new variational characterization of Gaussian diffusion processes as minimum uncertainty states. We then define a variational method constrained by kinematics of diffusions and Schr\"{o}dinger dynamics to seek states of local minimum uncertainty for general non-harmonic potentials.Comment: 11 pages, latex, 12pt A4wide, no figure

Dynamical control of qubit coherence: Random versus deterministic schemes

We revisit the problem of switching off unwanted phase evolution and decoherence in a single two-state quantum system in the light of recent results on random dynamical decoupling methods [L. Viola and E. Knill, Phys. Rev. Lett. {\bf 94}, 060502 (2005)]. A systematic comparison with standard cyclic decoupling is effected for a variety of dynamical regimes, including the case of both semiclassical and fully quantum decoherence models. In particular, exact analytical expressions are derived for randomized control of decoherence from a bosonic environment. We investigate quantitatively control protocols based on purely deterministic, purely random, as well as hybrid design, and identify their relative merits and weaknesses at improving system performance. We find that for time-independent systems, hybrid protocols tend to perform better than pure random and may improve over standard asymmetric schemes, whereas random protocols can be considerably more stable against fluctuations in the system parameters. Beside shedding light on the physical requirements underlying randomized control, our analysis further demonstrates the potential for explicit control settings where the latter may significantly improve over conventional schemes.Comment: 21 pages, 15 figures, to appear in Physical Review A, 72 (2005

Squeezing Inequalities and Entanglement for Identical Particles

By identifying non-local effects in systems of identical Bosonic qubits through correlations of their commuting observables, we show that entanglement is not necessary to violate certain squeezing inequalities that hold for distinguishable qubits and that spin squeezing may not be necessary to achieve sub-shot noise accuracies in ultra-cold atom interferometry.Comment: 13 pages, LaTe

Diritti umani e ragion pratica

L'articolo sostiene che la concezione aristotelica della ragion pratica \ue8 pi\uf9 capace di spiegare la pratica dei diritti umani rispetto alle concezioni alternative

Lo statuto normativo della dignit\ue0 umana

L'articolo affronta il problema dei rapporti fra il concetto di dignit\ue0 umana e il concetto di diritti uman

Energy harvester sensing

Our existence is immersed in a solution of energy, which is often left to degrade because we perceive this energy as expendable [...]

La vía europea de la razón pública

El futuro de Europa es una cuestión que aglutina todas las energías y recursos culturales, sin excluir a nadie. El elevado grado de conflictualidad presente en Europa se ha debido en buena parte a la consolidación de formas de vida nacionales, ligadas auna larga elaboración histórica en la que los aspectos religiosos y civiles se han entrelazado de modo inextricable. La amenaza representada por reivindicaciones de libertades despreocupadas del bien común invierte la óptica rawlsiana de la razón pública. ¿Cómo sociedades políticas preexistentes pueden acoger el pluralismo sin ser abrumadas por una progresiva e ineluctable fragmentación de la esfera pública?. La vía europea de la razón pública no será practicable si no se realiza una reconciliación entre la sociedad civil y política en el interior de los Estados miembros y, sin una conciencia pública europea que tenga en cuenta el "pluralismo"

L'obiezione di coscienza come diritto.

L'obiezione di coscienza ha un fondamento costituzionale nel diritto generale alla libert\ue0 religiosa e alla libert\ue0 di coscienza. Ma la coscienza ha un carattere complesso che presenta il profilo della formazione della coscienza e quello del giudizio pratico sulla conformit\ue0 del comportamento esteriore