Browsing by Subject "Mathematical physics"
Now showing items 120 of 31

A onephase Stefan problem with sizedependent thermal conductivity
(20180702)
Article
Open AccessIn this paper a onephase Stefan problem with sizedependent thermal conductivity is analysed. Approximate solutions to the problem are found via perturbation and numerical methods, and compared to the Neumann solution for ... 
A refined statistical cloud closure using doubleGaussian probability density functions
(20131008)
Article
Open AccessWe introduce a probability density function (PDF)based scheme to parameterize cloud fraction, average liquid water and liquid water flux in largescale models, that is developed from and tested against largeeddy simulations ... 
Controlling chaotic transport in twodimensional periodic potentials
(20101007)
Article
Open AccessWe uncover and characterize different chaotic transport scenarios in perfect twodimensional periodic potentials by controlling the chaotic dynamics of particles subjected to periodic external forces in the absence of a ... 
Direct Numerical Simulation of evaporative cooling at the lateral boundary of shallow cumulus clouds
(20130723)
Article
Open AccessThis study investigates the dynamics of the subsiding shell at the lateral boundary of cumulus clouds, focusing on the role of evaporative cooling. Since the size of this shell is well below what largeeddy simulations can ... 
Dynamical sectors for a spinning particle in AdS(3)
(American Physical Society, 20140912)
Article
Open AccessWe consider the dynamics of a particle of mass M and spin J in AdS(3). The study reveals the presence of different dynamical sectors depending on the relative values of M, J and the AdS(3) radius R. For the subcritical ... 
Dynamics of ManyBody Quantum Systems
(Universitat Politècnica de Catalunya, 20150703)
Bachelor thesis
Open AccessWe study the ground state and the excitations of quantum bose systems. The hypernetted chain equations (HNC) are introduced and we show that the methods based on them produce acceptable approximations of the static structure ... 
Factorization of the Fourier transform of the pressurePoisson equation using finite differences in colocated grids
(WileyVCH, 20120229)
Article
Open AccessThe zerodivergence constraint on the velocity field in the numerical simulation of incompressible flows can be reduced, in certain cases, to a set of onedimensional linear difference equations for the pressure. These ... 
Geometric HamiltonJacobi theory for higherorder autonomous systems
(20130909)
External research report
Open AccessThe geometric framework for the HamiltonJacobi theory is used to study this theory in the ambient of higherorder mechanical systems, both in the Lagrangian and Hamiltonian formalisms. Thus, we state the corresponding ... 
Geometric Quantization of real polarizations via sheaves
(201301)
External research report
Open AccessIn this article we develop tools to compute the Geometric Quantization of a symplectic manifold with respect to a regular Lagrangian foliation via sheaf cohomology. The starting point is the definition of representation ... 
Gravitational Particle Production in Massive Chaotic Inflation and the Moduli Problem
(201202)
Article
Restricted access  publisher's policyParticle production from vacuum fluctuations during inflation is briefly revisited. The moduli problem occurring with light particles produced at the end of inflation is addressed, namely the fact that some results are in ... 
Groupoids and Faà di Bruno Formulae for green functions in bialgebras of trees
(201207)
External research report
Open AccessWe prove a Faa di Bruno formula for the Green function in the bialgebra of Ptrees, for any polynomial endofunctor P. The formula appears as relative homotopy cardinality of an equivalence of groupoids. For suitable choices ... 
Groupoids and Faà di Bruno formulae for Green functions in bialgebras of trees
(2014)
Article
Restricted access  publisher's policyWe prove a Faà di Bruno formula for the Green function in the bialgebra of Ptrees, for any polynomial endofunctor P. The formula appears as relative homotopy cardinality of an equivalence of groupoids. 
Heterogenous meanfield analysis of a generalized voterlike model on networks
(Springer, 201203)
Article
Open AccessWe propose a generalized framework for the study of voter models in complex networks at the heterogeneous meanfield (HMF) level that (i) yields a unified picture for existing copy/invasion processes and (ii) allows for ... 
Higherorder mechanics: variational principles and other topics
(American Institute of Mathematical Sciences, 201312)
Article
Open AccessAfter reviewing the LagrangianHamiltonian unified formalism (i.e, the SkinnerRusk formalism) for higherorder (nonautonomous) dynamical systems, we state a unified geometrical version of the Variational Principles which ... 
Modelling shorefaceconnected sand ridges observed at the inner shelf of the Ebro delta
(Universitat Politècnica de Catalunya, 201806)
Bachelor thesis
Open AccessThe large amount of sand provided by coastal erosion in the river mouth and the combination between highspeed currents induced by Mistral wind and severe wavestorm events might have been the favourable conditions in the ... 
On the calculation of the Doptimal multisine excitation power spectrum for broadband impedance spectroscopy measurements
(201208)
Article
Open AccessThe successful application of impedance spectroscopy in daily practice requires accurate measurements for modeling complex physiological or electrochemical phenomena in a single frequency or several frequencies at different ... 
Quantum corrections in nanoplasmonics & deep neural network training with reverse supervision
(Universitat Politècnica de Catalunya, 201805)
Bachelor thesis
Open Access
Covenantee: Massachusetts Institute of TechnologyThe classical theory of plasmonics fails dramatically at geometric length scales below 30 nm, due to quantum phenomena like electronic spillout of the wave function, nonlocality and Landau damping. An alternative to the ... 
Rigidity of infinitesimal momentum maps
(2016)
Article
Open AccessIn this paper we prove rigidity theorems for Poisson Lie group actions on Poisson manifolds. In particular, we prove that close infinitesimal momentum maps associated to Poisson Lie group actions are equivalent using a ... 
Shortcuts to adiabaticity for the transport of matter waves
(Universitat Politècnica de Catalunya / Universitat Autònoma de Barcelona, 20130910)
Master thesis
Open Access[ANGLES] In this master thesis we investigate the quantum transport of a single neutral atom between doublewell and triplewell potentials. In particular, we study and implement the FastForward technique to speed up the ... 
Singularity Theorems
(Universitat Politècnica de Catalunya, 2016)
Bachelor thesis
Open AccessThe main singularity theorems are reviewed, and a detailed development of the required mathematical tools in their proofs is performed. Also, the plausibility and applicability of the assumptions of the theorems to realistic ...