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Inverse Scattering for Waveguides

Hiroshi Isozaki, Yaroslav Kurylev, Matti Lassas (2006/2007)

Séminaire de théorie spectrale et géométrie

We study the inverse scattering problem for a waveguide ( M , g ) with cylindrical ends, M = M c α = 1 N ( Ω α × ( 0 , ) ) , where each Ω α × ( 0 , ) has a product type metric. We prove, that the physical scattering matrix, measured on just one of these ends, determines ( M , g ) up to an isometry.

Inverse spectral results on even dimensional tori

Carolyn S. Gordon, Pierre Guerini, Thomas Kappeler, David L. Webb (2008)

Annales de l’institut Fourier

Given a Hermitian line bundle L over a flat torus M , a connection on L , and a function Q on M , one associates a Schrödinger operator acting on sections of L ; its spectrum is denoted S p e c ( Q ; L , ) . Motivated by work of V. Guillemin in dimension two, we consider line bundles over tori of arbitrary even dimension with “translation invariant” connections , and we address the extent to which the spectrum S p e c ( Q ; L , ) determines the potential Q . With a genericity condition, we show that if the connection is invariant under...

Involutive formulation and simulation for electroneutral microfluids

Bijan Mohammadi, Jukka Tuomela (2011)

ESAIM: Mathematical Modelling and Numerical Analysis - Modélisation Mathématique et Analyse Numérique

We study a microfluidic flow model where the movement of several charged species is coupled with electric field and the motion of ambient fluid. The main numerical difficulty in this model is the net charge neutrality assumption which makes the system essentially overdetermined. Hence we propose to use the involutive and the associated augmented form of the system in numerical computations. Numerical experiments on electrophoresis and stacking show that the completed system significantly improves...

Involutive formulation and simulation for electroneutral microfluids

Bijan Mohammadi, Jukka Tuomela (2011)

ESAIM: Mathematical Modelling and Numerical Analysis

We study a microfluidic flow model where the movement of several charged species is coupled with electric field and the motion of ambient fluid. The main numerical difficulty in this model is the net charge neutrality assumption which makes the system essentially overdetermined. Hence we propose to use the involutive and the associated augmented form of the system in numerical computations. Numerical experiments on electrophoresis and stacking show that the completed system significantly improves...

Involutivity of truncated microsupports

Masaki Kashiwara, Térésa Monteiro Fernandes, Pierre Schapira (2003)

Bulletin de la Société Mathématique de France

Using a result of J.-M. Bony, we prove the weak involutivity of truncated microsupports. More precisely, given a sheaf F on a real manifold and k , if two functions vanish on SS k ( F ) , then so does their Poisson bracket.

Isospectral deformations of closed riemannian manifolds with different scalar curvature

Carolyn S. Gordon, Ruth Gornet, Dorothee Schueth, David L. Webb, Edward N. Wilson (1998)

Annales de l'institut Fourier

We construct the first examples of continuous families of isospectral Riemannian metrics that are not locally isometric on closed manifolds , more precisely, on S n × T m , where T m is a torus of dimension m 2 and S n is a sphere of dimension n 4 . These metrics are not locally homogeneous; in particular, the scalar curvature of each metric is nonconstant. For some of the deformations, the maximum scalar curvature changes during the deformation.

Isospectral deformations of the Lagrangian Grassmannians

Jacques Gasqui, Hubert Goldschmidt (2007)

Annales de l’institut Fourier

We study the special Lagrangian Grassmannian S U ( n ) / S O ( n ) , with n 3 , and its reduced space, the reduced Lagrangian Grassmannian X . The latter is an irreducible symmetric space of rank n - 1 and is the quotient of the Grassmannian S U ( n ) / S O ( n ) under the action of a cyclic group of isometries of order n . The main result of this paper asserts that the symmetric space X possesses non-trivial infinitesimal isospectral deformations. Thus we obtain the first example of an irreducible symmetric space of arbitrary rank 2 , which is...

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