Mikko Alava

Complex Systems and Materials group at COMP, HUT

Research interests: physics of disordered and complex systems - see  our homepage.

My current research topics concentrate around strange shapes (or colors...)
in Nature. You can obtain one of these by simply tearing a sheet of paper
into two pieces.  The trail left by the "crack tip" is a self-affine fractal.  One of
the fundamental questions here is why is this so, and what is the Hurst exponent
that describes such a fractal.


The "experiment" results in crackling noise, typical of avalanching systems,
which we study both experimentally and theoretically.  Together by collaborators
Phani Nukala (Oak Ridge) and Stefano Zapperi (Roma, La Sapienza) we just finished
a review article on the theory of fracture:
Alava, M.J., Nukala, P.K.N.N., and Zapperi S., Statistical models of fracture, Advances in Physics 55, 349-476 (2006).
This is also on cond-mat, as this link shows (together with the abstract).

It is my intention to start to keep track of new developments on "statistical fracture",
and a suitable tool for this would of course be a BLOG.

I hope to be able to maintain it in the future, so as to include references to new publications et cetera.

An example of a crack in paper

Here is an example of the fracture surface from a sheet of paper. As is easy to see, it is a complicated thing. As is less easy to see, it does
have a "self-affine" nature: the fluctuations grow as the scale of observation is increased, and how strong those fluctuations around the
mean (position of the crack at a point) are, depends on the scale to a certain power - the roughness exponent.

I have also worked on things at the interface between statistical physics and combinatorial optimization and computer science, on non-equilibrium phenomena such as self-organized criticality and scale-free networks, and on applications such as the structure of disordered media (ie. paper). A recent review on that is this: Alava, M.J. and Niskanen, K.J., Physics of Paper, Reports on Progress in Physics 69, 669-724 (2006).

One particular research line has been the physics of imbibition (or multiphase flows) in random media,
and we wrote yet another review on that published as: Alava, Mikko, Dube, Martin, Rost, Martin,
Imbibition in Disordered Media, Advances in Physics 113, 83-176 (2004) which one can also find on cond-mat.

Finally, my publications are these days on the HUT/Laboratory of Physics web page, cond-mat etc...

Here are some links to scientific conferences I have organized recently:

In 2002,  THE HELSINKI-SPHINX WORKSHOP ON DISORDERED SYSTEMS

In 2003  A graduate course on Complexity Transitions in Optimization Problems

In 2004  The Sphinx-Nordita workshop on depinning at Nordita

In 2005  there was a little HU/HUT/Evergrow workshop in Helsinki on Networks and Algorithms

In 2006  I co-organized a symposium at the MMM2006 in Freiburg

In Oct. 2006  Then, we did a local fall school on Computer Science and Physics.

In 2007  there was  first a satellite to the 23rd Statphys in Perugia, Italy on Scaling and Fluctuations in Materials (me and Alberto Petri).

Then,  after the Statphys there was another satellite on the Physics of Distributed Information Systems (funded by Nordita and HUT), in Mariehamn, Aland.

In 2008,  I am a co-organizer for a program for the newly inaugurated Kavli Institute for Theoretical Physics, China in Beijing. This is on the physics of distributed ... (again)!

Then,  this will be followed by a similar program at Nordita, Stockhom (Sweden). Lots of good science expected....

Here are some talks that I have given recently:

First,  at Goettingen (2005) on Quantum Annealing (work published in JSTAT, 2006)

Then an ESF workshop in Turin, 2006  first, on crackling (1/f) noise in avalanching systems (related to the old SOC paradigm, JSTAT Lett. 2005)

and at the same meeting  on acoustic emission as a diagnostic of fracture physicsa

At Univ. des Saarlandes in 2005  I talked about theory of imbibition and fronts in that.

In Edinburg (Feb. 06)  I also talked about fracture (in paper) and its stat. mech. aspects.

At Plasticity 06 (Halifax)  I presented some recent work by Lasse Laurson and myself, on the stick-slip of a dislocation and a solute cloud.

Finally, at a MMM satellite in Wroclaw,   I talked about the theory of strength from the statistical mechanics viewpoint: what happens in particular in the presence of a defect and competing disorder.
This research is done often in collaboration; Phil Duxbury at Michigan State, Heiko Rieger at Saarbrucken, Joachim Krug (Cologen), Martin Dube (Trois-Rivieres), Cristian Moukarzel (Merida), Stefano Zapperi (Rome), Miguel Munoz (Granada), Ron Dickm an (Belo Horizonte), Martin Rost (Bonn), Phani Nukala (ORNL) are some of our foreign friends.

Jan Astrom (CSC), Tapio Ala-Nissila (HUT/HIP), Pekka Orponen (HUT/TCS)
Kaarlo Niskanen (KCL Paper Science Center), Juha Merikoski and Jussi Timonen
(Jyvaskyla)  are the 'local' ones in a random order.

Recent news: there is an European STREP project (FP6) called TRIGS, which started by January 1st 2007
to look at complexity, and, "triggering" in materials across many scales.

Teaching (2007):

Sometimes, sometimes not. Mostly I supervise my students...

The academic year I am responsible for the Kandidaattiseminaari, the 3rd year preparatory seminar for the candidate degree. If you are interested, here is the link.

If you need a thesis topic, or a MSc project, or a PhD project, here is a list of possible topics (contact me by email):

Hobbies:
Contact:

HUT/ Lab of Physics

358-9-451 3104, fax 451 3116, cell phone -050-4132 152

email mja@fyslab.hut.fi