Symmetry breaking

For other uses, see Symmetry breaking (disambiguation).
A ball is initially located at the top of the central hill (C). This position is an unstable equilibrium: a very small perturbation will cause it to fall to one of the two stable wells left (L) or right (R). Even if the hill is symmetric and there is no reason for the ball to fall on either side, the observed final state is not symmetric.

In physics, symmetry breaking is a phenomenon where a disordered but symmetric state collapses into an ordered, but less symmetric state.[1] This collapse is often one of many possible bifurcations that a particle can take as it approaches a lower energy state. Due to the many possibilities, an observer may assume the result of the collapse to be arbitrary. This phenomenon is fundamental to quantum field theory (QFT), and further, contemporary understandings of physics.[2] Specifically, it plays a central role in the Glashow–Weinberg–Salam model which forms part of the Standard model modelling the electroweak sector.

A (black) particle is always driven to lowest energy. In the proposed -Symmetric system, it has two possible (purple) states. When it spontaneously breaks symmetry, it collapses into one of the two states. This phenomenon is known as spontaneous symmetry breaking.
A 3D representation of a particle in a symmetric system (a Higgs Mechanism) before assuming a lower energy state

In an infinite system (Minkowski spacetime) symmetry breaking occurs, however in a finite system (that is, any real super-condensed system), the system is less predictable, but in many cases quantum tunneling occurs.[2][3] Symmetry breaking and tunneling relate through the collapse of a particle into non-symmetric state as it seeks a lower energy.[4]

Symmetry breaking can be distinguished into two types, explicit and spontaneous. They are characterized by whether the equations of motion fail to be invariant, or the ground state fails to be invariant.

  1. ^ Heylighen, Francis (2023). "Entanglement, Symmetry Breaking and Collapse: Correspondences Between Quantum and Self-Organizing Dynamics". Foundations of Science. 28. Brussels, Belgium: 85–107. doi:10.1007/s10699-021-09780-7. S2CID 4568832 – via SpringerLink.
  2. ^ a b Gross, David J. (1996-12-10). "The role of symmetry in fundamental physics". PNAS. 93 (25): 14256–14259. doi:10.1073/pnas.93.25.14256. PMC 34470. PMID 11607718.
  3. ^ Ohira, Ryutaro; Mukaiyama, Takashi; Toyoda, Kenji (2020-02-01). "Breaking rotational symmetry in a trapped-ion quantum tunneling rotor". Physical Review A. 101 (2). American Physical Society: 022106. arXiv:1907.07404. Bibcode:2020PhRvA.101b2106O. doi:10.1103/PhysRevA.101.022106.
  4. ^ Castellani, Elena; Teh, Nicholas; Brading, Katherine (2017-12-14). Edward, Zalta (ed.). "Symmetry and symmetry breaking". Stanford Encyclopedia of Philosophy (Fall 2021 ed.). Metaphysics Research Lab, Stanford University.