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- G Foltin, S Gnutzmann, U Smilansky
- 2004

In this paper we investigate the properties of nodal structures in random wave fields, and in particular we scrutinize their recently proposed connection with short-range percolation models. We propose a measure which shows the difference between monochromatic random waves, which are characterized by long-range correlations, and Gaussian fields with… (More)

- Georg Foltin
- 2003

We consider the signed density of extremal point of (two-dimensional) scalar fields with a Gaussian distribution. We assign a positive unit-charge to the maxima and minima of the function and a negative one to its saddles. At first, we compute the average density for a field in half-space with Dirichlet boundary conditions. Then we calculate the… (More)

- Georg Foltin
- 2001

We extend a Gaussian model for the two-dimensional Coulomb gas by a term which models the increase of charge fluctuations in the presence of an internal electrical field. The resulting Hamiltonian, expressed as a functional of the internal potential, has a surprising large scale limit: The additional term simply counts the number of maxima and minima of the… (More)

- Georg Foltin
- 1999

We study orientational order, subject to thermal fluctuations, on a fixed curved surface. We derive, in particular, the average density of zeros of Gaussian distributed vector fields on a closed Riemannian manifold. Results are compared with the density of disclination charges obtained from a Coulomb gas model. Our model describes the disordered state of… (More)

- G Foltin, S Gnutzmann, U Smilansky
- 2004

We study the distribution of shapes of nodal lines that appear in solutions of the Helmholtz wave equation. For this purpose, we define the density associated with a given shape of a nodal line, and consider its expectation value for Gaussian random fields. We compute the densities of some particular lines, and show that the densities obtained agree well… (More)

- Georg Foltin
- 2003

We consider the nodal domains of Gaussian random waves in two dimensions. We present a method to calculate the distribution of the number of nodal domains and the average connectivity with the help of auxiliary Potts-spins. An analytical approach could be helpful to decide whether the pattern of nodal domains belongs to the universality class of… (More)

- Georg Foltin
- 2003

We calculate correlation functions of the (signed) density of zeros of Gaussian distributed vector fields. We are able to express correlation functions of arbitrary order through the curvature tensor of a certain abstract Riemann Cartan or Riemannian manifold. As an application, we discuss one and two-point functions. The zeros of a two-dimensional Gaussian… (More)

- Y H Matsuda, N Abe, S Takeyama, H Kageyama, P Corboz, A Honecker +4 others
- Physical review letters
- 2013

The magnetization process of the orthogonal-dimer antiferromagnet SrCu2(BO3)2 is investigated in high magnetic fields of up to 118 T. A 1/2 plateau is clearly observed in the field range 84 to 108 T in addition to 1/8, 1/4, and 1/3 plateaus at lower fields. Using a combination of state-of-the-art numerical simulations, the main features of the high-field… (More)

- Georg Foltin
- 2002

We calculate correlation functions of the (charge) density of zeroes of Gaussian distributed vector fields. We are able to express correlation functions of arbitrary order through the curvature tensor of a certain abstract Riemann Cartan or Riemannian manifold. As an application, we discuss one and two point functions. The zeroes of a two dimensional… (More)

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