Physics:Quantum Spontaneous symmetry breaking
Quantum spontaneous symmetry breaking occurs when the equations or energy function of a system have a symmetry, but the state chosen by the system does not display that full symmetry. The idea is central to condensed matter physics and quantum field theory.[1]
In many systems, the symmetric state is unstable or energetically disfavored. The system settles into one of several equivalent lower-energy states, each of which breaks the original symmetry in a particular direction.
Order and fields
A common picture is the Mexican-hat potential: the top is symmetric, but the stable ground states form a ring of choices. Once one point on the ring is selected, the symmetry is no longer visible in the realized state.
In quantum field theory, spontaneous symmetry breaking explains how fields can acquire nonzero vacuum values. In the electroweak theory, this idea is connected with the Higgs mechanism and the masses of weak gauge bosons.
Physical examples
Examples include magnetization in ferromagnets, crystal formation, superfluid phases, superconductivity, and the Higgs field. The broken symmetry often gives rise to collective modes, domain structures, or special low-energy excitations.
The concept helps explain how simple symmetric laws can produce structured and asymmetric physical worlds.
See also
- Physics:Quantum Field Theory Gauge symmetry
- Physics:Quantum scalar field
- Physics:Quantum Electroweak theory
- Biography:Peter Higgs
References
Source attribution: Physics:Quantum Spontaneous symmetry breaking