1,721,118 research outputs found
Characterization of Gaussian quantum Markov semigroups
No full textWe give a characterization of QMSs on the Bosonic Fock Space Gamma(C-d) whose predual preserves the set of gaussian states. We show they can be obtained via certain generalized GKLS generators and they satisfy an explicit formula for their action on Weyl operators
On irreducibility of Gaussian quantum Markov semigroups
No full textThe generator of a Gaussian quantum Markov semigroup on the algebra of bounded operator on a d-mode Fock space is represented in a generalized GKLS form with an operator G quadratic in creation and annihilation operators and Kraus operators L1,... ,Lm linear in creation and annihilation operators. Kraus operators, commutators |G,L-l| and iterated commutators |G, |G,L-l||, horizontal ellipsis up to the order 2d - m, as linear combinations of creation and annihilation operators determine a vector in DOUBLE-STRUCK CAPITAL C-2d. We show that a Gaussian quantum Markov semigroup is irreducible if such vectors generate DOUBLE-STRUCK CAPITAL C-2d, under the technical condition that the domains of G and the number operator coincide. Conversely, we show that this condition is also necessary if the linear space generated by Kraus operators and their iterated commutator with G is fully non-commutative
I danni da lesione dell’identità e la riservatezza e l’illecito trattamento dei dati personali
No full textIl saggio rilegge le ragioni di politica del diritto alla base della tutela della riservatezza alla luce della complementarietà tra tutela amministrativa e azione civile nella tutela dei dati personali e del principio di qualificazione dell’ingiustizia del danno in ragione di una soglia minima di gravità dell’offesa.
Indicazioni de jure condito e condendo sono tratte con riferimento a questioni teoriche e pratiche quali il fondamento dei danni non patrimoniali e la funzione del risarcimento; l’opportunità di garantire un raccordo tra tutela amministrativa e tutela giurisdizionale a fronte di una violazione comune a entrambe; la possibilità di integrare la deterrenza nella struttura della tutela risarcitoria, accanto alla funzione primaria, solidaristico-satisfattiva; l’opportunità di introdurre dispositivi di coordinamento tra tutela amministrativa preventiva e tutela risarcitoria collettiva, in presenza di violazioni seriali ma difficili da apprezzare considerate isolatamente
Gaussian Quantum Markov Semigroups on a One-Mode Fock Space: Irreducibility and Normal Invariant States
No full textWe consider the most general Gaussian quantum Markov semigroup on a one-mode Fock space, discuss its construction from the generalized GKSL representation of the generator. We prove the known explicit formula on Weyl operators, characterize irreducibility and its equivalence to a Hörmander type condition on commutators and establish necessary and sufficient conditions for existence and uniqueness of normal invariant states. We illustrate these results by applications to the open quantum oscillator and the quantum Fokker-Planck model
Principal component analysis of the primordial tensor power spectrum
No full textWe study how the shape of the spectrum of primordial gravitational waves can be constrained by future experiments looking at the B-mode of the Cosmic Microwave Background (CMB) polarization. We implement a Principal Component Analysis (PCA) including the effects of diffuse foreground residuals, following component separation, in the uncertainty of CMB angular power spectra, and taking into account the gravitational lensing by Large Scale Structure. We perform our study by considering the capabilities of future B-mode CMB experiments such as LiteBIRD, the Simons Observatory (SO) and Stage-IV (CMB-S4), in particular in detecting deviations of the primordial tensor spectrum from the scale-invariant behavior. We find that diffuse foreground residuals impact substantially both the derivation of the PCA basis and the corresponding constraining power, in all cases. In particular, depending on which experimental specifications and which value r of tensor-to-scalar ratio for cosmological perturbations are considered, adding foregrounds residuals can determine an increase as large as a factor ∼ 4 both on the uncertainty on r and on the recovery of the PCA modes. We study the limitations of the methodology, including the effect of physicality priors on the PCA, which we quantify via a Monte Carlo Markov chain (MCMC) analysis of the combined cosmological and PCA power spectrum parameter space
The Decoherence-Free Subalgebra of Gaussian Quantum Markov Semigroups
No full textWe demonstrate a method for finding the decoherence-free subalgebra N(T) of a Gaussian quantum Markov semigroup on the von Neumann algebra B(Gamma(C-d)) of all bounded operator on the Fock space Gamma(C-d) on C-d. We show that N(T) is a type I von Neumann algebra L-infinity (R-dc;C)(circle times) over barB(Gamma(C-df)) determined, up to unitary equivalence, by two natural numbers d(c), d(f) <= d. This result is illustrated by some applications and examples
- …
