Exploració per tema "Mathematical physics"
Ara es mostren els items 1-20 de 46
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A one-phase Stefan problem with size-dependent thermal conductivity
(2018-07-02)
Article
Accés obertIn this paper a one-phase Stefan problem with size-dependent 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 double-Gaussian probability density functions
(2013-10-08)
Article
Accés obertWe introduce a probability density function (PDF)-based scheme to parameterize cloud fraction, average liquid water and liquid water flux in large-scale models, that is developed from and tested against large-eddy simulations ... -
Assessing the physics of models for transition in pipe flow
(Universitat Politècnica de Catalunya, 2022-07-06)
Treball Final de Grau
Accés obert
Realitzat a/amb: Universität Bremen / Zentrum für angewandte Raumfahrttechnologie und MikrogravitationTransition to turbulence in pipe flow is a long standing problem in the field of turbulence research. In the route to fully turbulent pipe flow, turbulence presents itself in a wide variety of forms. In recent years, a ... -
Computational methodologies for quasi-periodic orbits and invariant manifold connections in non-autonomous problems
(International Astronautical Federation (IAF), 2023)
Text en actes de congrés
Accés restringit per política de l'editorialSemi-analytical and numerical techniques to systematically analyze and compute natural connections between quasi-periodic orbits associated to non-autonomous systems are considered. Focusing in the non-autonomous Sun-Earth+Moon ... -
Controlling chaotic transport in two-dimensional periodic potentials
(2010-10-07)
Article
Accés obertWe uncover and characterize different chaotic transport scenarios in perfect two-dimensional periodic potentials by controlling the chaotic dynamics of particles subjected to periodic external forces in the absence of a ... -
Dilute quantum Bose gases beyond its limit of universality
(Universitat Politècnica de Catalunya, 2023-07-10)
Treball Final de Grau
Accés obertThe Bose equation of state has not progressed significantly since the universality regime discovery in terms of the s-wave scattering length, a. Nowadays no expansion exists to calculate the energy at higher densities, ... -
Direct Numerical Simulation of evaporative cooling at the lateral boundary of shallow cumulus clouds
(2013-07-23)
Article
Accés obertThis 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 large-eddy simulations can ... -
Dynamical sectors for a spinning particle in AdS(3)
(American Physical Society, 2014-09-12)
Article
Accés obertWe 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 Many-Body Quantum Systems
(Universitat Politècnica de Catalunya, 2015-07-03)
Treball Final de Grau
Accés obertWe 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 ... -
Eigenvalue curves for generalized MIT bag models
(Springer Nature, 2022-11-22)
Article
Accés obertWe study spectral properties of Dirac operators on bounded domains O¿R3 with boundary conditions of electrostatic and Lorentz scalar type and which depend on a parameter t¿R; the case t=0 corresponds to the MIT bag model. ... -
Exploration of the internal flux rope current density using a spacecraft constellation
(Universitat Politècnica de Catalunya, 2022-05)
Treball Final de Grau
Accés obert
Realitzat a/amb: Goddard Space Flight CenterDurant molts anys la comunitat científica ha estat treballant per entendre millor la topologia i les propietats físiques dels tubs de flux (flux ropes en anglès), car són una de les principals formes en les quals l’activitat ... -
Factorization of the Fourier transform of the pressure-Poisson equation using finite differences in colocated grids
(Wiley-VCH, 2012-02-29)
Article
Accés obertThe zero-divergence constraint on the velocity field in the numerical simulation of incompressible flows can be reduced, in certain cases, to a set of one-dimensional linear difference equations for the pressure. These ... -
Geometric Hamilton-Jacobi theory for higher-order autonomous systems
(2013-09-09)
Report de recerca
Accés obertThe geometric framework for the Hamilton-Jacobi theory is used to study this theory in the ambient of higher-order mechanical systems, both in the Lagrangian and Hamiltonian formalisms. Thus, we state the corresponding ... -
Geometric Quantization of real polarizations via sheaves
(2013-01)
Report de recerca
Accés obertIn 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 ... -
Global analysis of direct transfers from lunar orbits to sun-earth libration point regimes
(Springer Nature, 2021-04-01)
Article
Accés obertIn this paper we look forward to obtain a global picture of simple transfer opportunities from Lunar to Sun-Earth libration orbits, useful for a preliminary design of these mission scenarios. Considering the trajectory of ... -
Gravitational Particle Production in Massive Chaotic Inflation and the Moduli Problem
(2012-02)
Article
Accés restringit per política de l'editorialParticle 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
(2014)
Article
Accés restringit per política de l'editorialWe prove a Faà di Bruno formula for the Green function in the bialgebra of P-trees, for any polynomial endofunctor P. The formula appears as relative homotopy cardinality of an equivalence of groupoids. -
Groupoids and Faà di Bruno Formulae for green functions in bialgebras of trees
(2012-07)
Report de recerca
Accés obertWe prove a Faa di Bruno formula for the Green function in the bialgebra of P-trees, for any polynomial endofunctor P. The formula appears as relative homotopy cardinality of an equivalence of groupoids. For suitable choices ... -
Heterogenous mean-field analysis of a generalized voter-like model on networks
(Springer, 2012-03)
Article
Accés obertWe propose a generalized framework for the study of voter models in complex networks at the heterogeneous mean-field (HMF) level that (i) yields a unified picture for existing copy/invasion processes and (ii) allows for ... -
High order dynamical systems approaches for low-thrust station-keeping of libration point orbits
(2022-01-01)
Article
Accés obertWe derive two families of low-thrust station-keeping control procedures based on the dynamical properties of the phase space near libration point orbits. The first family is obtained as the limit of impulsive maneuvers, ...