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Homometric point sets and inverse problems

Grimm, Uwe and Baake, Michael (2008). Homometric point sets and inverse problems. Zeitschrift für Kristallographie, 223(11-12) pp. 777–781.

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The inverse problem of diffraction theory in essence amounts to the reconstruction of the atomic positions of a solid from its diffraction image. From a mathematical perspective, this is a notoriously difficult problem, even in the idealised situation of perfect diffraction from an infinite structure.

Here, the problem is analysed via the autocorrelation measure of the underlying point set, where two point sets are called homometric when they share the same autocorrelation. For the class of mathematical quasicrystals within a given cut and project scheme, the homometry problem becomes equivalent to Matheron´s covariogram problem, in the sense of determining the window from its covariogram. Although certain uniqueness results are known for convex windows, interesting examples of distinct homometric model sets already emerge in the plane.

The uncertainty level increases in the presence of diffuse scattering. Already in one dimension, a mixed spectrum can be compatible with structures of different entropy. We expand on this example by constructing a family of mixed systems with fixed diffraction image but varying entropy. We also outline how this generalises to higher dimension.

Item Type: Journal Article
Copyright Holders: 2008 Oldenbourg Wissenschaftsverlag, Mu¨nchen
ISSN: 0044-2968
Project Funding Details:
Funded Project NameProject IDFunding Body
Combinatorics of Sequences and Tilings and its ApplicationsEP/D058465/1EPSRC (Engineering and Physical Sciences Research Council)
Academic Unit/Department: Mathematics, Computing and Technology > Mathematics and Statistics
Item ID: 14992
Depositing User: Uwe Grimm
Date Deposited: 23 Feb 2009 14:08
Last Modified: 23 Mar 2014 15:37
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