Lesson 08

Phase Defects and Boundaries

A system can be locally ordered while preserving a global mismatch.

Neighbouring phases can align smoothly while the system as a whole still contains a twist, discontinuity or defect. Boundaries strongly influence whether that mismatch remains or disappears.

Ring of phase nodesW = 0winding number

Live explanation

What is happening?

Most neighbouring phases are aligned. No net winding around the ring.

Controls

Shape the field

Periodic wraps around, fixed pins the edges to 0°, free lets edges evolve freely.

1.20
0.15

Controls how quickly the phase field adjusts. (This model has no velocity, so this is not physical damping.)

What to notice

  • Local alignment does not guarantee global uniformity.
  • A complete phase winding cannot always be removed by a small local adjustment.
  • Boundaries can trap or release defects.
  • Opposite defects may cancel.

Show the maths

Optional — the intuition already covers the important ideas.

W = (1 / 2π) ∮ dΦ

W counts the net number of phase turns around a closed path. On the ring, W is the integer number of complete twists visible around the circle.

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