25-27 August 2008
Europe/Stockholm timezone
Search processes play an important role in physical, chemical, and biological systems, a prominent example playing the encounter of two molecules to perform a chemical reaction as quantified in the Smoluchowsky model. Recent interest is directed toward more complex search processes. In particular, gene regulation in biological cells has been very actively studied. Thus, transcription factors, specific DNA-binding proteins, need to search megabases of DNA in order to locate their specific binding site. According to the Berg-von Hippel model this occurs as a combination of volume (3D) search, 1D sliding diffusion along the DNA chain, and intersegmental transfers between remote segments of DNA brought close-by in the embedding space by DNA-looping. It has been argued that this looping gives rise to a Levy flight in the chemical coordinate along the DNA backbone. In vivo, addditional effects come into play, such as the observation that proteins actually subdiffuse. This could, inter alia, lead to a weak ergodicity breaking with potentially very beneficial effects for the efficiency and economy for the regulation process.

Search processes are also explored on a more general level. Levy flights have been identified to be a very efficient search strategy, as they combine local search and long excursions, as in the flight of the albatross or the walk of jackals. Intermittent search processes during which the searching agent switches between local diffusive search and relocations to a different local area, have been shown to optimize the search even further, in particular, when combined with Levy relocations.

This NORDITA workshop is intended to bring together leading scientists working on search models and exchange recent theoretical and experimental advances in the understanding and exploration of search processes from biochemical processes in cells up to the search of animals for food.
Roslagstullbacken 23 10691 Stockholm
Invited speakers (* confirmed):
Albert-Laszlo Barabasi* (Northeastern)
Olivier Benichou* (Paris)
Otto Berg* (Uppsala)
Dirk Brockmann* (Evanston)
Stas Burov* (Ramat Gan)
Edward Cox* (Princeton)
Maans Ehrenberg (Uppsala)
Johan Elf (Uppsala)
Ulrich Gerland* (Koeln)
John Hertz* (Copenhagen)
Joseph Klafter* (Tel Aviv)
Akihiro Kusumi (Kyoto University)
Michael Lomholt (Odense)
Jose Mateos* (Mexico City)
Ralf Metzler* (Munich)
Leonid Mirny (Cambridge MA)
Lene Oddershede* (Copenhagen)
Gleb Oshanin* (Paris)
Ingve Simonsen (Trondheim)
David Sims* (Plymouth, UK)
Igor Sokolov (Berlin)
Pieter Rein ten Wolde* (Amsterdam)
Matthias Weiss* (Heidelberg)
Bram van den Broek* (Amsterdam)
Sunney Xie (Cambridge MA)