There is a class of electronic liquids in dimensions greater than one, which show all essential properties of one dimensional electronic physics. These are topological liquids correlated electronic systems with a spectral flow. Compressible topological electronic liquids are superfluids. In this paper we present a study of a conventional model of a topological superfluid in two spatial dimensio...

We prove nonlinear stability in L 1 of planar shock front solutions to a viscous conservation law in two spatial dimensions, and obtain an expression for the asymptotic form of small perturbations. The leading-order behavior is shown rigorously to be governed by an eeective diiusion coeecient depending on forces transverse to the shock front. The proof is based on a spectral analysis of the lin...

We numerically perform a spectral analysis of a quasi-periodically driven spin 1/2 system, the spectrum of which is Singular Continuous. We compute fractal dimensions of spectral measures and discuss their connections with the time behaviour of various dynamical quantities, such as the moments of the distribution of the wave packet. Our data suggest a close similarity between the information di...

This paper addresses the design of arrayed waveguide grating (AWG) devices from the viewpoint of –3dB bandwidth and free spectral range. A straightforward numerical method of obtaining the physical dimensions of a real device for given – 3dB bandwidth and free spectral range is presented. The paper assesses also the influence of the –3dB bandwidth of the AWG on the performance of a dense wavele...

In the past few years we have been involved in the development and implementation of parallel finite element and pseudo-spectral methods for porous media flow. In this paper we present a brief review of our methods and show several examples of highly nonlinear simulations in two and three-dimensions, on different current high performance computers. New issues on finite element techniques and ps...

We prove that Nelson’s massless scalar field model is infrared divergent in three dimensions. In particular, the Nelson Hamiltonian has no ground state in Fock space and thus it is not unitarily equivalent with the Hamiltonian obtained from Euclidean quantization. In contrast, for dimensions higher than three the Nelson Hamiltonian has a unique ground state in Fock space and the two Hamiltonian...

We show that the Nonlinear Schrödinger Equation and the related Lax pair in 1+1 dimensions can be derived from 2+1 dimensional Chern-Simons Topological Gauge Theory. The spectral parameter, a main object for the Loop algebra structure and the Inverse Spectral Transform, has appear as a homogeneous part (condensate) of the statistical gauge field, connected with the compactified extra space coor...

A new (scalar) spectral decomposition is found for the Dirac system in two dimensions associated to the focusing Davey–Stewartson II (DSII) equation. Discrete spectrum in the spectral problem corresponds to eigenvalues embedded into a two-dimensional essential spectrum. We show that these embedded eigenvalues are structurally unstable under small variations of the initial data. This instability...

A generalization of the negative Camassa-Holm hierarchy to 2 + 1 dimensions is presented under the name CHH(2+1). Several hodograph transformations are applied in order to transform the hierarchy into a system of coupled CBS (Calogero-Bogoyavlenskii-Schiff) equations in 2 + 1 dimensions that pass the Painlevé test. A non-isospectral Lax pair for CHH(2+1) is obtained through the above mentioned ...

COMPUTATIONAL CAMERAS At Columbia University’s Computer Vision Laboratory, we have developed several types of computational cameras. As the “Related Research” sidebar describes, several research groups around the world are working on the development of computational cameras and related technologies. Imaging can be viewed as having several dimensions, including spatial resolution, temporal resol...