480 likes | 635 Views
Emerging Complexity in Physics How does Physical Complexity arise from Basic Particles and Simple Principles? Ronald Westra Dep. Mathematics Maastricht University November , 2005. Part 1 Simple versus Complex. Emergent Complexity in Physics UCM Course LS213 –2005/2006.
E N D
Emerging Complexity in Physics How does Physical Complexity arise from Basic Particles and Simple Principles? Ronald Westra Dep. Mathematics Maastricht UniversityNovember, 2005
Part 1 Simple versus Complex
Emergent Complexity in Physics UCM Course LS213 –2005/2006
Emergent Complexity in Physics UCM Course LS213 –2005/2006
Emergent Complexity in Physics UCM Course LS213 –2005/2006
ABOUT “COMPLEXITY” … ‘complexity’ : synonym with difficult, problematical, and tough, opposite to ‘simplicity’. ‘complexity’ : fuzzy and relative; differing from person to person and theory and praxis. In science the concept of complexity in some cases assumes a more tangible meaning.
COMPLEXITY in science In the mathematical context complexity often correlates to the notion of computability. Mathematical complexity theory: the ‘combinatorial complexity’ of an algorithm is precisely defined in terms of algorithmic iterations and the size of the problem.
COMPLEXITY in science In Computer Science there is an objective measure of the complexity of an object : The Kolmogorov-Chaitin complexity: ~ the number of symbols required to specify an object in any conceivable formal language.
COMPLEXITY in science In natural sciences the concept of complexity is not precisely defined. What are the characteristics and conditions for complexity in physics? How does complexity originate? Can complexity evolve from simplicity? Can we distinguish conditions and laws for complexity?
TYPES of COMPLEXITY intrinsic versus extrinsic complexity. compare the physical world of interacting elementary particles to a classical theater with various dramatis personae ‘intrinsic’ complexity refers to the complexity of one specific player or the plot of the play, ‘extrinsic’ complexity refers to the complexity that stems from increasing the number of actors involved in our drama. Can complex systems evolve from merely increasing the number of effectively simple agents?
What is ‘complexity’ ??? Intrinsic Complexity?
(NON) LINEARITY Linear system : any combination of subsystems behaves exactly similar, and any linear scaling results in a similar system. Linear system : time evolution result in similar systems. Linear system : open for mathematical scrutiny, hence understanding, hence predictability. Linear systems are systems that obey the superpositionprinciple; any two solutions of the system van be added together to form a valid new solution. In contrast, two solutions of a nonlinear equationcannot be added together to form another solution.
Linear dynamics: laminar flow Non-linear dynamics: turbulent flow
GUIDING PRINCIPLES in NATURE The laws physical systems for evolution towards complexity. Examples : Self-organization, Self-Organized Criticality. Conservation Laws: Energy, Momentum, Angular Momentum, Particle-type
GUIDING PRINCIPLES in NATURE The laws of Nature: Are there laws of Nature ???
CHALLENGES IN CURRENT PHYSICS • The most complete theoriy in physics, the Standard Model, is incomplete (does not include gravity) and phenomenological (contains free parameters) and does not have an appealing mathematical structure. • From Astronomy it has becone clear that there is much more mass in the Universe than we can observe. • We now observe that the expansion of the Universe defies the models for Cosmology.
Emergent Complexity in Physics UCM Course LS213 –2005/2006
Emergent Complexity in Physics UCM Course LS213 –2005/2006
Emergent Complexity in Physics UCM Course LS213 –2005/2006
Emergent Complexity in Physics UCM Course LS213 –2005/2006
Emergent Complexity in Physics UCM Course LS213 –2005/2006
Emergent Complexity in Physics UCM Course LS213 –2005/2006
Inorganic molecules Organic molecules External energy Prebiotic Evolution Organisms Cycle of increasing complexity Biotic Evolution