quasi-crystals
A newly discovered state of matter exhibiting forbidden symmetries, such as fivefold rotational symmetry, challenging classical crystallographic constraints.
1 chapter across 1 book
The Emperor's New Mind (1989)Roger Penrose
This chapter explores the limitations of determinism and computability in quantum mechanics, proposing that a new, non-algorithmic theory (CQG) may govern the quantum-classical boundary, allowing determinism without computability and potentially preserving free will. It also discusses the anthropic principle in both its weak and strong forms, evaluating its implications for consciousness and the universe. Finally, the chapter introduces quasi-crystals, highlighting their unusual fivefold symmetry that challenges classical crystallographic theorems and recounts their experimental discovery.