Physics of Information
Physics 28A
Syllabus (Winter)
Instructor: Prof. Jim Crutchfield (chaos@ucdavis.edu; http://csc.ucdavis.edu/~chaos)
WWW: http://csc.ucdavis.edu/~chaos/courses/poci/
Contents
1 First Lecture: Overview
Readings (available via course website):
- Chaos, JP Crutchfield, JD Farmer, NH Packard, RS Shaw, Scientific American 255 (1986)
46–57.
- Odds, Stanislaw Lem, New Yorker 54 (1978) 38–54.
Topics:
- Introduction and motivations
- Physics of Information 256A: Dynamics, Self-Organization, Measurement Theory, Information
Theory
- Physics of Computation 256B
- Survey interests, background, and abilities
- Course logistics
- Exams
- CMPy Labs
2 Self-Organization
Reading: Nonlinear Dynamics and Chaos, Strogatz (NDAC), and Course Lecture Notes
Theme: Forms of Randomness, Order, and Intrinsic Instability
- Nonlinear Dynamics:
- Qualitative dynamics
- ODEs and maps
- Bifurcations
- Stability, instability, and chaos
- Quantifying (in)stability
- Pattern-forming systems:
- Instability and stabilization of patterns
- Cellular automata, map lattices, spin systems
2.1 Lecture 2: The Big Picture
Reading: NDAC, Chapters 1 and 2.
Topics:
- Pendulum demo
- Discuss Chaos and Odds readings and homework
- Qualitative dynamics: A geometric view of behavior
- State space
- Flows
- Attractors
- Basins
- Submanifolds
- Concrete, but simple example: One-dimensional flows
Homework: Assign Week 0’s homework today. Everyday unpredictability; see handout or website. Due in
one week, but be prepared to discuss at next meeting.
2.2 Lecture 3: Example Dynamical Systems
Reading: NDAC, Sections 6.0-6.7, 7.0-7.3, and 9.0-9.4.
Topics:
- Continuous-time ODEs
- 2D flows: Fixed points (Sec. 6.0-6.4)
- 2D flows: Limit cycles (Sec. 7.0-7.3)
- 3D flows: Chaos in Lorenz (Sec. 9.0-9.4)
- Simulation demo
- From continuous to discrete time (Sec. 9.4)
- Poincaré maps and sections
- Lorenz ODE to cusp map
- Rössler ODE to logistic map (pp. 376–379)
- Discrete-time maps
2.3 Lecture 4: The Big, Big Picture I
Reading: NDAC, Chapters 3 and 8 and Sec. 10.0-10.4.
Topics:
- Qualitative dynamics: Space of all dynamical systems
- Example: Bifurcations of one-dimensional flows
- Saddle node
- Transcritical
- Pitchfork
- Catastrophe theory
- Catastrophes: Fixed point to fixed point bifurcation
- Example: Cusp Catastrophe
- Catastrophe theory classification of fixed point bifurcations
Homework: Collect Week 0’s, assign Week 1’s today.
2.4 Lecture 5: The Big, Big Picture II
Reading: NDAC, Chapters 3 and 8 and Sec. 10.0-10.4.
Topics:
- Bifurcations in discrete-time maps: Logistic map
- Fixed point to limit cycle
- Phenomenon and calculation
- Limit cycle to limit cycle
- Phenomenon and calculation
- Routes to chaos: Period-doubling cascade
- Phenomenon and calculation
- Band-merging
- Periodic windows and intermittency
- Simulation demo
2.5 Lecture 6: Mechanism of Chaos: Stable Instability
Reading: NDAC, Sec. 12.0-12.3, 9.3, and 10.5.
Topics:
- Chaotic mechanisms: Stretch and fold
- Baker’s map
- Cat map (and stretch demo)
- Henon map: stretch-fold and self-similarity
- Roessler attractor branched manifold
- Dot spreading: Roessler and Lorenz ODEs
- Lyapunov characteristic exponents (LCEs)
- Time to unpredictability
- Dissipation rate
- Attractor LCE classification
- Chaos defined
Homework: Collect Week 1’s, assign Week 2’s today.
2.6 Lecture 7: Example Chaotic Maps (that you can analyze)
Reading: NDAC, Chapter 10.
Topics:
- Shift map
- LCEs for maps
- Tent map
- Logistic map
- LCE view of period-doubling route to chaos
- Period-doubling self-similarity
- Renormalization group analysis of scaling
2.7 Lecture 8: Pattern Formation I
Reading: Lecture Notes.
Topics:
- Review last lecture.
- Spatially Extended Dynamical Systems
- Synchronous Cellular Automata
- Lattice Maps: Logistic Lattice and Dripping Handrail
Homework: Collect Week 2’s, assign Week 3’s today.
2.8 Lecture 9: Pattern Formation II
Reading: Lecture Notes.
Topics:
- Review last lecture.
- Asynchronous Cellular Automata
- Spin Systems
3 From Determinism to Stochasticity
Reading: Lecture Notes.
Theme: Stochasticity and Measurement
- Probability Theory of Dynamical Systems
- Stochastic Processes
- Measurement Theory
3.1 Lecture 10: Probability Theory of Dynamical Systems
Reading: Lecture Notes.
Topics:
- Probability theory review
- Dynamical evolution of distributions
- Invariant measures
- Examples
Homework: Collect Week 3’s, assign Week 4’s today.
3.2 Lecture 11: Stochastic Processes
Reading: Lecture Notes.
Topics:
- Review last lecture.
- Processes
- Markov chains
- Statistical equilibrium
- Hidden Markov models
- Examples: Fair coin, periodic, golden mean, even, and others
3.3 Lecture 12: Measurement Theory I
Reading: Lecture Notes.
Topics:
- Review last lecture.
- State-space partitioning
- Orbit and sequence spaces
- Good instruments and informative measurements
Homework: Collect Week 4’s, assign Week 5’s today.
3.4 Lecture 13: Measurement Theory II
Reading: Lecture Notes.
Topics:
- Review last lecture.
- Markov partitions in 1D
- Generating partitions in 1D
- Example: 1D maps
- Generating partitions in 2D
- Example: 2D Cat map
4 Information Processing
Reading: Elements of Information Theory, Cover and Thomas (EIT), and Computational Mechanics
Reader, JPC (CMR)
Theme: Information, Uncertainty, and Memory
- Entropies
- Communication Channel (and coding theorems)
- Mutual Information and Information metric
- Excess Entropy
- Transient Information
- Connection to Dynamics: Entropy rate and LCEs
4.1 Lecture 14: Entropies
Reading: EIT, Chapters 1 and 2.
Topics:
- Motivation: Information ≠ Energy
- Information as uncertainty and surprise
- Information sources: Ignorance of forces or initial conditions, deterministic chaos, and ...?
- Axioms for a measure of information
- Entropy function
- Convexity
- Joint and Conditional Entropy
- Mutual information
- Examples
Homework: Collect Week 5’s, assign Week 6’s today.
4.2 Lecture 15: Information in Processes I
Reading: EIT, Sec. 5-5.4 and 8-8.5 and Chapter 4.
Topics:
- Communication channels
- Coding theorems
- Examples
4.3 Lecture 16: Information in Processes II
Reading: EIT, Sec. 5-5.4 and 8-8.5 and Chapter 4.
Topics:
- Entropy rates for Markov chains
- Entropies for times series
- Connection to Dynamics: Entropy rate and LCEs
Homework: Collect Week 6’s, assign Week 7’s today.
4.4 Lecture 17: Memory in Processes I
Reading: CMR article RURO.
Topics:
- Entropy convergence
- Excess entropy
- Examples
4.5 Lecture 18: Memory in Processes II
Reading: CMR article RURO.
Topics:
- Generalized synchronization
- Transient information
- Examples
Homework: Collect Week 7’s, assign Week 8’s today.
4.6 Lecture 19: Rate Distortion Theory I
Reading: EIT, Chapter 10.
Topics:
- Rate distortion theory
4.7 Lecture 20: Rate Distortion Theory II
Reading: EIT, Chapter 10.
Topics:
- Rate distortion theory
Homework: Collect Week 8’s.