Search results for "Geometric"
showing 10 items of 652 documents
Editorial message
2006
Geometric Computing and Reasoning (GCR) is a new track of SAC and it is dedicated to the recent trends in the domain of geometric constraint solving and automated, or computer aided, deduction in geometry.
The Impact of the Mass Spectrum of Lenses in Quasar Microlensing Studies. Constraints on a Mixed Population of Primordial Black Holes and Stars
2020
We show that quasar microlensing magnification statistics induced by a population of point microlenses distributed according to a mass-spectrum can be very well approximated by that of a single-mass, "monochromatic", population. When the spatial resolution (physically defined by the source size) is small as compared with the Einstein radius, the mass of the monochromatic population matches the geometric mean of the mass-spectrum. Otherwise, the best-fit mass can be larger. Taking into account the degeneracy with the geometric mean, the interpretation of quasar microlensing observations under the hypothesis of a mixed population of primordial black holes and stars, makes the existence of a s…
Variable kinematics models and finite elements for nonlinear analysis of multilayered smart plates
2015
Abstract A variable kinematics approach for moderately large deflection analysis of smart magneto-electro-elastic multilayered plates is presented. The approach is based on the condensation of the electro-magnetic state into the plate kinematics, whose nonlinear strain–displacement relationships are expressed in the von Karman sense. This leads to models resulting in an effective mechanical plate, which takes the multifield coupling effects into account by the plate stiffness, inertia and loading characteristics, consistently defined as combinations of the layers material properties. By a unified approach, both equivalent single layer and layerwise models are developed formulating the assoc…
Geometric phase induced by a cyclically evolving squeezed vacuum reservoir
2006
We propose a new way to generate an observable geometric phase by means of a completely incoherent phenomenon. We show how to imprint a geometric phase to a system by "adiabatically" manipulating the environment with which it interacts. As a specific scheme we analyse a multilevel atom interacting with a broad-band squeezed vacuum bosonic bath. As the squeezing parameters are smoothly changed in time along a closed loop, the ground state of the system acquires a geometric phase. We propose also a scheme to measure such geometric phase by means of a suitable polarization detection.
Observable geometric phase induced by a cyclically evolving dissipative process
2006
In a prevous paper (Phys. Rev. Lett. 96, 150403 (2006)) we have proposed a new way to generate an observable geometric phase on a quantum system by means of a completely incoherent phenomenon. The basic idea was to force the ground state of the system to evolve ciclically by "adiabatically" manipulating the environment with which it interacts. The specific scheme we have previously analyzed, consisting of a multilevel atom interacting with a broad-band squeezed vacuum bosonic bath whose squeezing parameters are smoothly changed in time along a closed loop, is here solved in a more direct way. This new solution emphasizes how the geometric phase on the ground state of the system is indeed du…
Connection between optimal control theory and adiabatic-passage techniques in quantum systems
2012
This work explores the relationship between optimal control theory and adiabatic passage techniques in quantum systems. The study is based on a geometric analysis of the Hamiltonian dynamics constructed from the Pontryagin Maximum Principle. In a three-level quantum system, we show that the Stimulated Raman Adiabatic Passage technique can be associated to a peculiar Hamiltonian singularity. One deduces that the adiabatic pulse is solution of the optimal control problem only for a specific cost functional. This analysis is extended to the case of a four-level quantum system.
Boundary behavior of quasi-regular maps and the isodiametric profile
2001
We study obstructions for a quasi-regular mapping f : M → N f:M\rightarrow N of finite degree between Riemannian manifolds to blow up on or collapse on a non-trivial part of the boundary of M M .
On the 1-handles of the product V3XBn for a simply connected open 3-manifold V3
2013
Although \pi_1^\inftyV^3 is an obstruction for killing stably the 1-handles of an open simply connected 3-manifold V^3, one can always get rid of the 1-handles of V^3\times B^n, for high enough n, at price of a certain nonmetrizable slackening of the topology.
Architettura in alzato. Questioni di territorio, paesaggio, ambiente
2021
Negata alla tipologia l’architettura del Sud nel saggio riconosce una specifica identità e perfetta eccezionalità nell’essenza del luogo. Se la facciata istituisce un rapporto con l’estetica del paesaggio, i temi che essa sottende definiscono altre significative relazioni. L’ordinamento logico delle membrature, la chiarezza geometrica e il rigore dei rapporti rimandano ad una architettura che si misura, ed è misura stessa, del territorio e della sua morfologia. A sua volta, lo spessore della facciata esprime la relazione con l’ambiente e interpreta in maniera poetica i condizionamenti climatici, intervenendo sul controllo della luce, sui vuoti nei paramenti murari, sulla determinazione dell…