Search results for "thermal [correlation function]"

Flavour mixing transport theory and resonant leptogenesis

2021

We derive non-equilibrium quantum transport equations for flavour-mixing fermions. We develop the formalism mostly in the context of resonant leptogenesis with two mixing Majorana fermions and one lepton flavour, but our master equations are valid more generally in homogeneous and isotropic systems. We give a hierarchy of quantum kinetic equations, valid at different approximations, that can accommodate helicity and arbitrary mass differences. In the mass-degenerate limit the equations take the familiar form of density matrix equations. We also derive the semiclassical Boltzmann limit of our equations, including the CP-violating source, whose regulator corresponds to the flavour coherence d…

Quantum transport and the phase space structure of the Wightman functions

2019

We study the phase space structure of exact quantum Wightman functions in spatially homogeneous, temporally varying systems. In addition to the usual mass shells, the Wightman functions display additional coherence shells around zero frequency $k_0=0$, which carry the information of the local quantum coherence of particle-antiparticle pairs. We find also other structures, which encode non-local correlations in time, and discuss their role and decoherence. We give a simple derivation of the cQPA formalism, a set of quantum transport equations, that can be used to study interacting systems including the local quantum coherence. We compute quantum currents created by a temporal change in a par…

Non-equilibrium dynamics of a scalar field with quantum backreaction

2021

We study the dynamical evolution of coupled one- and two-point functions of a scalar field in the 2PI framework at the Hartree approximation, including backreaction from out-of-equilibrium modes. We renormalize the 2PI equations of motion in an on-shell scheme in terms of physical parameters. We present the Hartree-resummed renormalized effective potential at finite temperature and critically discuss the role of the effective potential in a non-equilibrium system. We follow the decay and thermalization of a scalar field from an initial cold state with all energy stored in the potential, into a fully thermalized system with a finite temperature. We identify the non-perturbative processes of …

Black hole evaporation in a thermalized final-state projection model

2007

4 pages, 1 figure.-- PACS nrs.: 04.70.Dy; 03.67.-a.-- ISI Article Identifier: 000245333600044.-- ArXiv pre-print available at: http://arxiv.org/abs/hep-th/0611152

Space and Time Averaged Quantum Stress Tensor Fluctuations

2021

We extend previous work on the numerical diagonalization of quantum stress tensor operators in the Minkowski vacuum state, which considered operators averaged in a finite time interval, to operators averaged in a finite spacetime region. Since real experiments occur over finite volumes and durations, physically meaningful fluctuations may be obtained from stress tensor operators averaged by compactly supported sampling functions in space and time. The direct diagonalization, via a Bogoliubov transformation, gives the eigenvalues and the probabilities of measuring those eigenvalues in the vacuum state, from which the underlying probability distribution can be constructed. For the normal-orde…

THE EFFECT OF GADOLINIUM ON THE ESR RESPONSE OF ALANINE AND AMMONIUM TARTRATE EXPOSED TO THERMAL NEUTRONS

2008

Many efforts have been made to develop neutron capture therapy (NCT) for cancer treatment. Among the challenges in using NCT is the characterization of the features of the mixed radiation field and of its components. In this study, we examined the enhancement of the ESR response of pellets of alanine and ammonium tartrate with gadolinium oxide exposed to a thermal neutron beam. In particular, the ESR response of these dosimeters as a function of the gadolinium content inside the dosimeter was analyzed. We found that the addition of gadolinium improves the sensitivity of both alanine and ammonium tartrate. However, the use of gadolinium involves a reduces in or abolishes tissue equivalence b…

The role of transportation and its involved sources of energy in the environmental assessment of marble producing sites

2018

Marble is acquiring large popularity as building material. Since building materials are now required to be characterized by high energy and environmental performances, marble is entailed to fulfill top-level requirements. About its environmental performances an important European Decision establishes criteria for the award of the Community eco-label to this material. Unfortunately, this Decision is focused on mining and processing activities, seemingly neglecting marble transport. In contrast, this phase affects the whole working chain because it releases (pollutant) emissions and involves the use of primary and, in case, secondary energy sources. Here, the focus is on the role played by tr…

Water diffusion and swelling stresses in ionizing radiation cured epoxies as matrices for carbon fiber composites

2017

Cross-linking polymerization initiated by high energy radiation is a very attractive technique for the production of high performance composite materials. This method in fact offers many advantages compared to conventional thermal curing processes, due to the possibility to operate at mild temperature and in short time, limiting both energy and time consuming [1-2]. High performance composite materials mainly consist of epoxy resins as matrix and carbon fibers as reinforce, due to their excellent properties in terms of thermal and mechanical resistance. An important requirement of such systems for structural applications is their ability to maintain the properties within a fixed range durin…

Injectable Hydrogel for Synergetic Low Dose Radiotherapy, Chemodynamic Therapy and Photothermal Therapy

2021

Higher doses of radiotherapy (RT) are associated with resistance induction, therefore highly selective and controllable radiosensitizers are urgently needed. To address this issue, we developed a FeGA-based injectable hydrogel system (FH) that can be used in combination with low-dose radiation. Our FH can deliver FeGA directly to the tumor site via intratumoral injection, where it is a reservoir-based system to conserve FeGA. The photothermal properties of FeGA steadily dissolve FH under laser irradiation, and, simultaneously, FeGA reacts with a large amount of H2O2 in the cell to produce OH (Fenton reaction) which is highly toxic to mitochondria, rendering the cell inactive and reducing ra…

Il miglioramento energetico nel recupero degli edifici storici. Applicazione al patrimonio architettonico palermitano

L'architettura storica può assumere un ruolo rilevante nel raggiungimento degli obiettivi europei di efficienza energetica per il settore edile, obiettivi che, tuttavia, devono essere compatibili con la conservazione del patrimonio storico e del suo valore culturale. A tal fine è necessario far riferimento ai caratteri specifici dell'architettura storica e alla sua dimensione locale. La presente tesi, sulla base di tale assunto, esamina le prestazioni energetiche degli edifici storici e il loro potenziale miglioramento, concentrandosi sul patrimonio architettonico di Palermo, caso di studio significativo per l'area mediterranea. La ricerca, condotta con riferimento sia alla scala urbana sia…