View source for Giorgio Parisi

'''Giorgio Parisi''' (born August 4, 1948) is an Italian [[theoretical physicist]], whose research has focused on [[quantum field theory]], [[statistical mechanics]], and [[complex systems]].

== Biography ==

His best known contributions are:

* The [[Quantum chromodynamics]] evolution equations for parton densities known as the Altarelli-Parisi or DGLAP equations
* The exact solution of the Sherrington-Kirkpatrick model of [[spin glasses]]
* The [[Kardar–Parisi–Zhang equation]] describing dynamic scaling of growing interfaces
* The study of whirling flocks of birds - see [[Flocking (behavior)]]

== Flocking mathematics ==

Parisi has studied whirling flocks of birds (circa 2006):

<blockquote>Starlings are very interesting because they make very fast movements in the air. They move very straight, very fast, and this is done by thousands and thousands of them. One of the problems is how do they communicate in order to have this collective movement done together?</blockquote>

Parisi estimates having taken approximately 100,000 photographs of starling flocks in the air. 

Starling flocks provide a convenient, measurable example of a complex system.

Parisi:

<blockquote>They may seem very far from [[spin glasses]], but there is something in common.  What they share, and what is very interesting, is how complex behaviors arise. This is a theme recurrent in physics and biology, and most of the research that I have done is to get at this thing: how complex collective behavior may arise from elements that each have a simple behavior."</blockquote>

Source: http://www.pnas.org/content/103/21/7945.full

== See also ==

* [[Flocking (behavior)]]
* [[Kardar–Parisi–Zhang equation]]
* [[Spin glass]]

== External links ==

* [https://en.wikipedia.org/wiki/Giorgio_Parisi Giorgio Parisi] @ Wikipedia
* [http://www.pnas.org/content/103/21/7945.full Profile of Giorgio Parisi]

[[Category:Mathematicians]]
[[Category:People]]
[[Category:Theoretical physicists]]