Mathematics of quasicrystals - MathOverflow most recent 30 from http://mathoverflow.net 2013-06-19T02:36:19Z http://mathoverflow.net/feeds/question/99914 http://www.creativecommons.org/licenses/by-nc/2.5/rdf http://mathoverflow.net/questions/99914/mathematics-of-quasicrystals Mathematics of quasicrystals erkant 2012-06-18T16:26:23Z 2012-06-20T06:00:47Z <p>I want to study quasicrystals from mathematical point of view, but I'm having hard time finding materials about it. If you could suggest me some books, articles or papers, I would be glad.</p> http://mathoverflow.net/questions/99914/mathematics-of-quasicrystals/99915#99915 Answer by Joseph O'Rourke for Mathematics of quasicrystals Joseph O'Rourke 2012-06-18T16:41:37Z 2012-06-18T16:41:37Z <p><em>Quasicrystals and Geometry</em> by Marjorie Senechal. A bit dated (1996) but still a place to start. (<a href="http://www.amazon.com/Quasicrystals-Geometry-Marjorie-Senechal/dp/0521575419" rel="nofollow">Amazon link</a>). <br /> &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;<img src="http://cs.smith.edu/~orourke/MathOverflow/Senechal.jpg" alt="Senechal Figure"></p> http://mathoverflow.net/questions/99914/mathematics-of-quasicrystals/99921#99921 Answer by Jon Paprocki for Mathematics of quasicrystals Jon Paprocki 2012-06-18T17:14:51Z 2012-06-18T17:41:03Z <p>If you are interested in the non-commutative geometry side of things, there is an overview article, <em><a href="http://people.math.gatech.edu/~jeanbel/Publi/ncg02.pdf" rel="nofollow">The Noncommutative Geometry of Aperiodic Solids</a></em> (pdf link) by Jean Bellissard. He writes the paper building up from the most basic possible physical concepts and makes the use of noncommutative geometry to study quasicrystals seem quite natural, and it is done in a mathematically rigorous manner. Edit: I should emphasize that this paper is about the physical side of quasicrystals, written from a mathematical perspective. I wasn't sure if that was what you wanted, as opposed to just the mathematical study of quasicrystals without regard for any related physics.</p> http://mathoverflow.net/questions/99914/mathematics-of-quasicrystals/99967#99967 Answer by Igor Pak for Mathematics of quasicrystals Igor Pak 2012-06-19T03:58:00Z 2012-06-19T03:58:00Z <p>You might want to consider reading the following excellent introduction to the subject:<br> Charles Radin, "<a href="http://www.amazon.com/Miles-Tiles-Student-Mathematical-Library/dp/082181933X/ref=cm_cr_pr_product_top" rel="nofollow">Miles of tiles</a>", AMS, 1999.</p> http://mathoverflow.net/questions/99914/mathematics-of-quasicrystals/100013#100013 Answer by Algernon for Mathematics of quasicrystals Algernon 2012-06-19T15:18:39Z 2012-06-19T15:41:37Z <p>Here is a hard-to-find but worthy book from the point of view of statistical mechanics:</p> <ul> <li><a href="http://www.mimuw.edu.pl/~miekisz/" rel="nofollow">Jacek Miękisz</a>, Quasicrystals - Microscopic models of nonperiodic structure, Louven University Press, 1993.</li> </ul> <p>There has been some progress since the writing of the book, but the main question (the construction of a lattice-gas model with translation-invariant finite range interactions admitting a quasi-crystalline phase) remains open.</p> <p>If you don't like statistical mechanics, there is enormous literature on <a href="http://en.wikipedia.org/wiki/Aperiodic_tiling" rel="nofollow">aperiodic tilings</a>. The book</p> <ul> <li>B. Grunbaum, G. C. Shephard, <a href="http://www.goodreads.com/book/show/234991.Tilings_and_Patterns" rel="nofollow">Tilings and Patterns</a>, W. H. Freeman and Co., 1986</li> </ul> <p>has two chapters on aperiodic tilings. For a more up-to-date account, I would recommend the <a href="http://users.utu.fi/jkari/tilings/" rel="nofollow">lecture notes</a> of Jarkko Kari.</p> <p>If you tell us more specifically, which aspect of it you would like to study, maybe we could help better.</p> http://mathoverflow.net/questions/99914/mathematics-of-quasicrystals/100059#100059 Answer by Chris Gerig for Mathematics of quasicrystals Chris Gerig 2012-06-19T23:14:55Z 2012-06-19T23:14:55Z <p>My favorite paper on this stuff is <strong>Applications of Group Cohomology to the Classification of Quasicrystal Symmetries</strong> (by Fisher and Rabson)<br> <a href="http://iopscience.iop.org/0305-4470/36/40/005/pdf/0305-4470_36_40_005.pdf" rel="nofollow">http://iopscience.iop.org/0305-4470/36/40/005/pdf/0305-4470_36_40_005.pdf</a><br> They take the work of David Mermin and recast it in terms of cohomology, lattices, and fourier space. So they start from scratch and define what a quasicrystal is. At the end they give some examples where electron-degeneracy and diffraction patterns arise as certain homology classes.</p> <p>If you want to study <em>symmetries</em>, then there is Howard Hiller's note <strong>Crystallography and Cohomology of Groups</strong><br> <a href="http://mathdl.maa.org/images/upload_library/22/Ford/Hiller765-779.pdf" rel="nofollow">http://mathdl.maa.org/images/upload_library/22/Ford/Hiller765-779.pdf</a><br> which handles exactly that. Associated to this is the notion of a <em>crystallographic group</em> $\mathbb{Z}^n\rtimes\mathbb{Z}_p$.</p> http://mathoverflow.net/questions/99914/mathematics-of-quasicrystals/100067#100067 Answer by Mahmud for Mathematics of quasicrystals Mahmud 2012-06-20T01:09:28Z 2012-06-20T01:09:28Z <ul> <li><a href="http://www.ams.org/notices/200608/whatis-senechal.pdf" rel="nofollow">What is a quasicrystal?</a> (AMS paper by Senechal)</li> <li><a href="http://www.quasi.iastate.edu/Bib.html" rel="nofollow">A PartialBibliography of Literature on Quasicrystals</a> </li> <li><a href="http://arxiv.org/abs/math-ph/9901014" rel="nofollow">A guide to mathematical quasicrystals</a> (arXiv, author: Baake)</li> <li><a href="http://en.wikipedia.org/wiki/Quasicrystal" rel="nofollow">Quasicrystal</a> (Wikipedia)</li> <li><a href="http://xenon.phys.psu.edu/Quasicrystals.htm" rel="nofollow">Quasicrystal surfaces</a> (PennState)</li> <li><a href="http://www.tau.ac.il/~ronlif/quasicrystals.html" rel="nofollow">Quasicrystals - Introduction by Ron Lifshitz</a></li> <li><a href="http://www.jcrystal.com/steffenweber/qc.html" rel="nofollow">Introduction to Quasicrystals</a></li> <li><a href="http://www.nature.com/news/2007/070219/full/news070219-9.html" rel="nofollow">Islamic tiles reveal sophisticated maths</a></li> <li><a href="http://www.saudiaramcoworld.com/issue/200905/the.tiles.of.infinity.htm" rel="nofollow">The Tiles of Infinity</a> (Saudi Aramco World article)</li> <li><a href="http://www.oldenbourg-link.com/doi/abs/10.1524/zkri.219.7.391.35643" rel="nofollow">Twenty years of structure research on quasicrystals. Part I. Pentagonal, octagonal, decagonal and dodecagonal quasicrystals</a> by Walter Steurer</li> <li>An informal article titled: *<a href="http://www.myscience.cc/news/2012/quasicrystal_is_extraterrestrial_in_origin_princeton_researchers_find-2012-princeton" rel="nofollow">Quasicrystal is extraterrestrial in origin, Princeton researchers find</a>*in myScience website</li> <li><a href="http://met.iisc.ernet.in/~lord/webfiles/tcq.html" rel="nofollow">Tilings, coverings, clusters and quasicrystals</a></li> <li><a href="http://euler.phys.cmu.edu/widom/research/qc/quasi.html" rel="nofollow">Quasicrystals</a></li> <li><a href="http://www.crystallography.fr/mathcryst/pdf/ECM22-MaThCryst-Abstracts.pdf" rel="nofollow">Paper from European Crystallographic Meeting, 2004</a></li> <li><a href="http://www.goldennumber.net/quasi-crystals/" rel="nofollow">Quasi-crystals and the Golden Ratio</a></li> <li><a href="http://www.lassp.cornell.edu/lifshitz/quasicrystals.html" rel="nofollow">Quasicrystals</a> (another intro material from Cornell) </li> <li><a href="http://www.nobelprize.org/mediaplayer/index.php?id=1624&amp;view=7" rel="nofollow">Announcement of the 2011 Nobel Prize in Chemistry</a> (8 minute video) </li> <li><a href="http://nvlpubs.nist.gov/nistpubs/sp958-lide/300-302.pdf" rel="nofollow">Quasicrystals</a> (a two page article) </li> </ul> <p>and finally a technical paper:</p> <ul> <li><a href="http://euler.phys.cmu.edu/widom/pubs/PDF/MRS03_LL2.3.1.pdf" rel="nofollow">Quasicrystal approximants with novel compositions and structures</a></li> </ul> http://mathoverflow.net/questions/99914/mathematics-of-quasicrystals/100077#100077 Answer by Misha for Mathematics of quasicrystals Misha 2012-06-20T06:00:47Z 2012-06-20T06:00:47Z <p>The trouble with the <em>quasicrystals</em> is that the literature in this area is dominated by non-mathematical or pseudo-mathematical papers and books. In particular, just extracting a mathematical definition of a quasicrystal from this literature is not so easy. This situation is well-illustrated by the wikipedia article on quasicrystals and the MO discussion of this topic at <a href="http://mathoverflow.net/questions/98171/what-is-the-relation-between-quasicrystals-riemann-hypothesis-and-pv-numbers" rel="nofollow">http://mathoverflow.net/questions/98171/what-is-the-relation-between-quasicrystals-riemann-hypothesis-and-pv-numbers</a></p> <p>The two papers that I found most enlightening and mathematical, address this problem head-on (more on this below): </p> <p>[1]. A. Hof, "On diffraction by aperiodic structures", Commun. Math. Phys., 169 (1995), p. 25-43. </p> <p>[2]. J-B. Gouere, "Quasicrystals and almost periodicity", Commun. Math. Phys., 255 (2005), p. 655-681.</p> <p>Both papers prove some nontrivial mathematical theorems, on the basis of these theorems one can then form two, somewhat different, mathematical definitions of a (quasi)crystal. Senchal's 2-page long survey paper (see Mahmud's answer) or, better, her book (see Joseph's answer) is a good introduction, the trouble is that she does not prove anything in the book and that she could be sloppy with her definitions, for instance, she conflates functions, measures and distributions, which are needed for defining crystals. </p> <p>If you look in Senchal's book, you first get the following physical definitions of crystals: "A crystal is any solid with essentially discrete diffraction diagram." (This includes both traditional crystals and quasicrystals.) The word "essentially" will be the difference between different mathematical definitions, which one derives from [1] and [2]. </p> <p>A (mathematical) quasicrystal is a tiling $T$ of ${\mathbb R}^n$ by convex polytopes satisfying certain properties: </p> <ol> <li><p>Since general tilings are hard to work with, pretty much everybody assumes that $T$ is a Voronoi tiling of ${\mathbb R}^n$ based on a certain discrete subset $N\subset {\mathbb R}^n$, which a geometer would call a <em>separated net</em>. </p></li> <li><p>Unfortunately, just having a separated net is not enough in order to deal with the "diffraction" issue. There is a disagreement which tilings are allowed as crystals and which are not. There is a general agreement that at least all <em>periodic tilings</em> (the ones where $N$ is a finite union of orbits of a discrete group of translations) and certain tilings constructed by Penrose and others via <em>projection method</em>, should be counted as crystals and quasicrystals respectively. I will call these two classes of tilings as "standard." </p></li> </ol> <p>a. Here is Hof's definition of a crystal (Senchal's definition is taken from Hof's paper). Hof in [1] takes the <em>auto-correlation function</em> (actually, a distribution) $\gamma$ of $N$ and computes the (appropriately defined) Fourier transform $\hat\gamma$ of $\gamma$ (this is a mathematical interpretation of the "diffraction diagram"). Then $\hat\gamma$ is a measure $\mu$ which, in general, splits as a sum of two measures $\mu_d+\mu_c$: <em>Discrete</em> part $\mu_d$, which is supported on a certain countable subset of ${\mathbb R}^n$ and <em>continuous</em> part $\mu_c$. He proposes that "essentially discrete diffraction" means that $\mu_d$ is nonzero. Hof then proves that "standard" tilings indeed have nontrivial $\mu_d$ (According to [2], Hof even proves that $\mu_c=0$ in this case, but I did not check this). The trouble with this definition is that, as far as I can tell, there is no known purely geometric interpretation of the condition $\mu_d\ne 0$ in terms of the next $N$ itself (at least, none existed 6 years ago). </p> <p>b. Gouere [2] (his work is an extension of Hof's approach and of a work by Lagarias) works with a slightly different definition, i.e., that $\mu_c=0$ (such sets $N$ are called <em>Patterson sets</em>). His main result is a purely geometric interpretation (actually, several interpretations) of this condition, see Theorem 1.1 in [1]: Patterson sets are the sets which are almost periodic with respect to Besikovitch's metric. </p> <p>Remark 1. As far as I can tell from reading Freeman Dyson's paper <a href="http://www.math.ucdavis.edu/~oyounggo/books/dyson.pdf" rel="nofollow">here</a>, definition of a quasicrystal that Dyson proposes is the one with $\mu_c=0$. </p> <p>Remark 2. Gouere does not propose that a <em>Patterson set</em> is the right definition of a crystal, this is just my take on his paper. Condition $\mu_c=0$ is more limited, but, in view of [2], is geometric and also covers "standard" examples, while the condition $\mu_d\ne 0$ is more general, but is nongeometric. </p>