Search results for " protect"

Topological Phases in Planar Electrodynamics

2001

This section is meant to be an extension of Chap. 31 on the quantal Berry phases. In particular, we are interested in studying the electromagnetic interaction of particles with a nonzero magnetic moment in \(D = 2 + 1\) dimensions and of translational invariant configurations of \((D = 3 + 1)\)-dimensional charged strings with a nonzero magnetic moment per unit length. The whole discussion is based on our article in Physical Review D44, 1132 (1991).

Brachytherapy structural shielding calculations using Monte Carlo generated, monoenergetic data

2014

Purpose: To provide a method for calculating the transmission of any broad photon beam with a known energy spectrum in the range of 20–1090 keV, through concrete and lead, based on the superposition of corresponding monoenergetic data obtained from Monte Carlo simulation. Methods: MCNP5 was used to calculate broad photon beam transmission data through varying thickness of lead and concrete, for monoenergetic point sources of energy in the range pertinent to brachytherapy (20–1090 keV, in 10 keV intervals). The three parameter empirical model introduced byArcher et al. [“Diagnostic x-ray shielding design based on an empirical model of photon attenuation,” Health Phys. 44, 507–517 (1983)] was…

Topological transitions from multipartite entanglement with tensor networks: a procedure for sharper and faster characterization

2014

Topological order in a 2d quantum matter can be determined by the topological contribution to the entanglement R\'enyi entropies. However, when close to a quantum phase transition, its calculation becomes cumbersome. Here we show how topological phase transitions in 2d systems can be much better assessed by multipartite entanglement, as measured by the topological geometric entanglement of blocks. Specifically, we present an efficient tensor network algorithm based on Projected Entangled Pair States to compute this quantity for a torus partitioned into cylinders, and then use this method to find sharp evidence of topological phase transitions in 2d systems with a string-tension perturbation…

Noncompact Topological Quantum Groups

1995

A star-product construction of quantum semisimple real Lie groups is performed for the noncompact case.

Topological field theory

1991

Topological protection of highly entangled non-Gaussian two-photon states

2021

Abstract We study theoretically the evolution of entangled non-Gaussian two-photon states in disordered topological lattices. Specifically, we consider spatially entangled two-photon states, modulated by Laguerre polynomials up to the 3rd order, which feature ring-shaped spatial and spectral correlation patterns. Such states are discrete analogs of photon-subtracted squeezed states, which are ubiquitous in optical quantum information processing or sensing applications. We find that, in general, a higher degree of entanglement coincides with a loss of topological protection against disorder, this is in line with previous results for Gaussian two-photon states. However, we identify a particul…

Radiation dose distribution around a mobile linear accelerator Mobetron using Monte Carlo simulation

2016

The aim of this work is to analyze the scattered radiation produced by the mobile accelerator Mobetron. To do so detailed Monte Carlo simulation using two different codes, Penelope2011 and Geant4, were performed. Experimental measurements were also done to validate them. To quantify the attenuation of the internal structures present in the accelerator head on the scattered radiation produced, some of the main structural shielding in the Mobetron has been incorporated into the simulation. Results are compared with experimental measurements. Some discrepancies between the calculated and measured dose values were found. These differences can be traced back to the importance of the radiation co…

Vides zinātne un pārvalde

1996

Rakstu krājumā apkopoti pētījumu rezultāti, par kuriem rakstu autori referēja Latvijas Universitātes 54. zinātniskās konferences Vides zinātnes un pārvaldes sekcijā.

RESPONSABILITÉ EST PLANIFICATION. OEdipe planificateur de la ville du présent.

2016

Il contributo analizza e individua scenari di sviluppo per una condizione particolarmente sensibile quale quella in cui i grandi valori del patrimonio culturale e paesaggistico si intrecciano con le richiesta di trasformazione. La relazione, quindi, tra la pianificazione territoriale e una visione strategicamente orientata per la valutazione delle risorse ambientali viene individuata come una possibile soluzione alla crescita senza controllo e come risolutore della condizione di conflitto determinato dalla assenza di relazioni tra tutelato e non tutelato. Le document analyse et identifie les scénarios de développement pour une condition particulièrement sensible: les grandes valeurs du pays…

Physiological,anatomical and biomass partitioning responses to ozone in the Mediterranean endemic plant Lamottea dianae

2011

Ozone effects on the perennial forb Lamottea dianae were studied in an open-top chamber experiment. Ozone was found to induce reductions in CO 2 assimilation and water use efficiency in the leaves of this species. These reductions were mainly related to a decline in the in vivo CO 2 fixation capacity of Rubisco (V c,max), rather than to stomatal limitations or photoinhibitory damage (F v:F m). In addition to chloroplast degeneration, other observed effects were callose accumulation, formation of pectinaceous wart-like cell wall exudates and phloem alterations. Moreover, ozone exposure significantly reduced root dry biomass. The possible relevance of these adverse effects for Mediterranean f…