Peter Grassberger (born 17 May 1940) is a retired professor who worked in statistical and
particle physics
Particle physics or high energy physics is the study of fundamental particles and forces that constitute matter and radiation. The fundamental particles in the universe are classified in the Standard Model as fermions (matter particles) an ...
. He made contributions to
chaos theory, where he introduced the idea of
correlation dimension In chaos theory, the correlation dimension (denoted by ''ν'') is a measure of the dimensionality of the space occupied by a set of random points, often referred to as a type of fractal dimension.
For example, if we have a set of random points on t ...
, a means of measuring a type of
fractal dimension
In mathematics, more specifically in fractal geometry, a fractal dimension is a ratio providing a statistical index of complexity comparing how detail in a pattern (strictly speaking, a fractal pattern) changes with the scale at which it is me ...
of the
strange attractor.
Work
Grassberger's early work focused on particle phenomenology, in particular on the formulation of formally exact equations for three-body scattering and bound state scattering (Alt-Grassberger-Sandhas equation).
While working at
CERN, he realized that reggeon field theory can be viewed as a
contact process in the same
universality class
In statistical mechanics, a universality class is a collection of mathematical models which share a single scale invariant limit under the process of renormalization group flow. While the models within a class may differ dramatically at finite s ...
as
directed percolation
In statistical physics, directed percolation (DP) refers to a class of models that mimic filtering of fluids through porous materials along a given direction, due to the effect of gravity. Varying the microscopic connectivity of the pores, these ...
. After making this discovery, Grassberger turned his attention to the studies of
statistical physics
Statistical physics is a branch of physics that evolved from a foundation of statistical mechanics, which uses methods of probability theory and statistics, and particularly the mathematical tools for dealing with large populations and approxim ...
,
dynamical systems, sequential sampling algorithms, and
complex systems. His publications span a variety of topics including
reaction-diffusion systems,
cellular automata
A cellular automaton (pl. cellular automata, abbrev. CA) is a discrete model of computation studied in automata theory. Cellular automata are also called cellular spaces, tessellation automata, homogeneous structures, cellular structures, tessel ...
,
fractals
In mathematics, a fractal is a geometric shape containing detailed structure at arbitrarily small scales, usually having a fractal dimension strictly exceeding the topological dimension. Many fractals appear similar at various scales, as illus ...
,
Ising model
The Ising model () (or Lenz-Ising model or Ising-Lenz model), named after the physicists Ernst Ising and Wilhelm Lenz, is a mathematical model of ferromagnetism in statistical mechanics. The model consists of discrete variables that represent ...
, Griffiths phases,
self-organized criticality
Self-organized criticality (SOC) is a property of dynamical systems that have a critical point as an attractor. Their macroscopic behavior thus displays the spatial or temporal scale-invariance characteristic of the critical point of a phase ...
, and
percolation
Percolation (from Latin ''percolare'', "to filter" or "trickle through"), in physics, chemistry and materials science, refers to the movement and filtering of fluids through porous materials.
It is described by Darcy's law.
Broader applicatio ...
.
He held long-term positions at the
University of Wuppertal
The University of Wuppertal (''Universität Wuppertal'') is a German scientific institution, located in Wuppertal, in the state of North Rhine-Westphalia, Germany.
The university's official name in German is ''Bergische Universität Wuppertal'' ...
and at the
Forschungszentrum Jülich
Forschungszentrum Jülich (FZJ here for short) is a national research institution that pursues interdisciplinary research in the fields of energy, information, and bioeconomy. It operates research infrastructures with a focus on supercomputers. Cu ...
(Germany). Other positions that lasted between 2 years and 3 months were at
CERN, at the Universities of Kabul, Nice, Calgary, Rome and Utrecht, the
Weizmann Institute
The Weizmann Institute of Science ( he, מכון ויצמן למדע ''Machon Vaitzman LeMada'') is a public research university in Rehovot, Israel, established in 1934, 14 years before the State of Israel. It differs from other Israeli univ ...
, the
Max Planck Institute for the Physics of Complex Systems
The Max Planck Institute for the Physics of Complex systems is one of the 80 institutes of the Max-Planck-Gesellschaft, located in Dresden, Germany.
Research
The research at the institute in the field of the physics of complex systems rang ...
in Dresden, the in Florence, and at the
Institute for Advanced Studies in Basic Sciences
Institute for Advanced Studies in Basic Sciences (IASBS) (Persian: دانشگاه تحصیلات تکمیلی علوم پایه زنجان, ''Daneshgah-e Tehesilât-e Tekimili-ye Olum-e Paih-e Zanjaan'') also known as Zanjan Graduate Universit ...
in Zanjan, Iran.
In 2017 he received the
EPS Statistical and Nonlinear Physics Prize.
See also
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Complex network
In the context of network theory, a complex network is a graph (network) with non-trivial topological features—features that do not occur in simple networks such as lattices or random graphs but often occur in networks representing real ...
*
Epidemic models on lattices
Classic epidemic models of disease transmission are described in Compartmental models in epidemiology. Here we discuss the behavior when such models are simulated on a lattice.
Introduction
The mathematical modelling of epidemics was originally ...
*
Mutual information
In probability theory and information theory, the mutual information (MI) of two random variables is a measure of the mutual dependence between the two variables. More specifically, it quantifies the " amount of information" (in units such ...
*
Forecasting complexity
*
Kolmogorov entropy
In mathematics, a measure-preserving dynamical system is an object of study in the abstract formulation of dynamical systems, and ergodic theory in particular. Measure-preserving systems obey the Poincaré recurrence theorem, and are a special cas ...
Selected publications
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References
External links
Peter Grassberger's Homepage
Austrian physicists
People associated with CERN
Academic staff of the University of Calgary
Living people
1940 births
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