Day 28 - Hallmarks of Chaos

Conceptualizing the Lyapunov Exponent

Trajectories diverge exponentially in time

Announcements

  • Midterm 1 is graded
  • Homework 7 is due Friday
    • No homework next week
  • Midterm 2 will be assigned next Monday (due 18 April)
    • Second project check-in

Seminars This Week

WEDNESDAY, March 26, 2025

  • Astronomy Seminar, 1:30 pm, 1400 BPS, Bryan Terrazas, Oberlin College, Galaxy evolution and feedback modeling
  • FRIB Nuclear Science Seminar, 3:30pm., FRIB 1300 Auditorium, Dr. Jacklyn Gates of Lawrence Berkeley National Laboratory, Toward Pursuing New Superheavy Elements

Seminars This Week

THURSDAY, March 27, 2025

  • Special FRIB/MSU Nuclear Science Seminar with
    Colloquium
    , 3:30 pm, 1415 BPS, Mandie Gehring, LANL, Measuring Intense X-ray Spectra and an Overview of Space Research at Los Alamos National Laboratory

FRIDAY, March 28, 2025

  • IReNA Online Seminar, 2:00 pm, In Person and Zoom, FRIB 2025 Nuclear Conference Room, Jordi José, Technical University of Catalonia, UPC (Barcelona, Spain), Classical novae at the crossroads of nuclear physics, astrophysics and cosmochemistry

Hallmarks of a Classically Chaotic System

  1. Deterministic
  2. Sensitive to Initial Conditions
  3. Non-periodic Behavior
  4. Strange Attractors
  5. Parameter Sensitivity
  6. (Sometimes) Periodic Behavior

Limit Cycle

A limit cycle is a closed trajectory in phase space that is an attractor for a dynamical system.

The Van der Pol Oscillator exhibits a limit cycle.

Random initial conditions converge to a limit cycle. Modeled with .

The Lyapunov Exponent

is the separation vector between two trajectories in phase space .

Do trajectories diverge exponentially in time, ?

Each phase coordinate can change at a different rate: .

Largest ? Chaotic system.

Chen Attractor

Strange Attractors

A strange attractor is a set of points in phase space that a chaotic system approaches.

Chen Attractor

, , .

Interactive 3D Model

Example 1: Duffing Equation

Exhibits Periodic and Chaotic Behavior

Illustrates period doubling bifurcations as route to chaos

Example 2: Lorenz System

Exhibits sensitive dependence on initial conditions
Demonstrates the concept of a strange attractor