Search results for " master"

Geometric phase in open systems.

2003

We calculate the geometric phase associated to the evolution of a system subjected to decoherence through a quantum-jump approach. The method is general and can be applied to many different physical systems. As examples, two main source of decoherence are considered: dephasing and spontaneous decay. We show that the geometric phase is completely insensitive to the former, i.e. it is independent of the number of jumps determined by the dephasing operator.

Spin-lattice relaxation of individual solid-state spins

2018

Understanding the effect of vibrations on the relaxation process of individual spins is crucial for implementing nanosystems for quantum information and quantum metrology applications. In this work, we present a theoretical microscopic model to describe the spin-lattice relaxation of individual electronic spins associated to negatively charged nitrogen-vacancy centers in diamond, although our results can be extended to other spin-boson systems. Starting from a general spin-lattice interaction Hamiltonian, we provide a detailed description and solution of the quantum master equation of an electronic spin-one system coupled to a phononic bath in thermal equilibrium. Special attention is given…

Reconstruction of time-dependent coefficients: a check of approximation schemes for non-Markovian convolutionless dissipative generators

2010

We propose a procedure to fully reconstruct the time-dependent coefficients of convolutionless non-Markovian dissipative generators via a finite number of experimental measurements. By combining a tomography based approach with a proper data sampling, our proposal allows to relate the time-dependent coefficients governing the dissipative evolution of a quantum system to experimentally accessible quantities. The proposed scheme not only provides a way to retrieve full information about potentially unknown dissipative coefficients but also, most valuably, can be employed as a reliable consistency test for the approximations involved in the theoretical derivation of a given non-Markovian convo…

The Two Loop Crossed Ladder Vertex Diagram with Two Massive Exchanges

2008

We compute the (three) master integrals for the crossed ladder diagram with two exchanged quanta of equal mass. The differential equations obeyed by the master integrals are used to generate power series expansions centered around all the singular (plus some regular) points, which are then matched numerically with high accuracy. The expansions allow a fast and precise numerical calculation of the three master integrals (better than 15 digits with less than 30 terms in the whole real axis). A conspicuous relation with the equal-mass sunrise in two dimensions is found. Comparison with a previous large momentum expansion is made finding complete agreement.

Quantum collision models: Open system dynamics from repeated interactions

2022

We present an extensive introduction to quantum collision models (CMs), also known as repeated interactions schemes: a class of microscopic system-bath models for investigating open quantum systems dynamics whose use is currently spreading in a number of research areas. Through dedicated sections and a pedagogical approach, we discuss the CMs definition and general properties, their use for the derivation of master equations, their connection with quantum trajectories, their application in non-equilibrium quantum thermodynamics, their non-Markovian generalizations, their emergence from conventional system-bath microscopic models and link to the input-output formalism. The state of the art o…

Ultrafast Carrier Redistribution in Single InAs Quantum Dots Mediated by Wetting-Layer Dynamics

2019

Optical studies of single self-assembled semiconductor quantum dots (QDs) have been a topic of intensive investigation over the past two decades. Due to their solid-state nature, their electronic and optical emission properties are affected by the particular crystal structure as well as many-body-carrier interactions and dynamics. In this work, we use a master equation for microstates (MEM) model to study the carrier capture and escape from single QDs under optical nonresonant excitation and under the influence of a two-dimensional (2D) carrier reservoir (the wetting layer). This model reproduces carrier dynamics from power-dependent and time-resolved microphotoluminescence experiments . Du…

Preliminary Plan for the recovery of the asphalt mines of the Irminio Valley

2008

Environmental effects of energy policy in sicily: The role of renewable energy

2007

The saving of primary energy from fossil fuels and the promotion of exploitation of renewable sources are two of the most relevant goals to be achieved in order to match the climate protection target fixed by the Kyoto Protocol in 1997. For Italy, the commitment is the reduction of the greenhouse emissions by 6.5% below 1990 levels over the commitment period 2008–2012. It requires the introduction of suitable political strategies and programmes aimed to establish a sustainable energy system together with the application of a set of actions either at national scale, either at regional one. This study presents the results of a survey in the context of the Regione Sicilia about the potential s…

A bottom-up method for evaluating the whole energy demand of large residential building stocks: an application to a regional scale

2013

In this paper a method is described, originally conceived during the compilation of the Energy and Environmental Regional Plan of Sicily, aimed to: a) set up a lay-out model of an overall regional residential estate into a certain number of different building and heating system types; b) calculate the energy needs of every single type according to the procedures established by the national and European regulations; The method is particularly designed to evaluate the possible energy savings from the implementation of different interventions concerning the envelope and the HVAC systems to the various building types. The method, although based on several assumptions, shows to be reliable enoug…

Master in Cinema Pubblicitario in Digitale. Film pubblicitari

2010

Prodotto multimediale a contenuto scientifico sulle sperimentazioni artistico-tecnologiche effettuate nell'ambito del master in Cinema Pubblicitario in Digitale ed. 2010