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A theory that is asymmetric with respect to chiralities is called a chiral theory, while a non-chiral (i.e., parity-symmetric) theory is sometimes called a vector theory. Many pieces of the Standard Model of physics are non-chiral, which is traceable to anomaly cancellation in chiral theories.
The non-chiral Su–Schrieffer–Heeger model (=), can be associated with symmetry class BDI with an integer topological invariant due to gauge invariance. [6] [7] The problem is similar to the integer quantum Hall effect and the quantum anomalous Hall effect (both in =) which are A class, with integer Chern number.
It is possible to include both Dirac and Majorana mass terms in the same theory, which (in contrast to the Dirac-mass-only approach) can provide a “natural” explanation for the smallness of the observed neutrino masses, by linking the right-handed neutrinos to yet-unknown physics around the GUT scale [6] (see seesaw mechanism).
At low energies, type IIA string theory is described by type IIA supergravity in ten dimensions which is a non-chiral theory (i.e. left–right symmetric) with (1,1) d=10 supersymmetry; the fact that the anomalies in this theory cancel is therefore trivial.
Many other familiar objects exhibit the same chiral symmetry of the human body, such as gloves, glasses (sometimes), and shoes. A similar notion of chirality is considered in knot theory, as explained below. Some chiral three-dimensional objects, such as the helix, can be assigned a right or left handedness, according to the right-hand rule.
In physics, topological order [1] is a kind of order in the zero-temperature phase of matter (also known as quantum matter). Macroscopically, topological order is defined and described by robust ground state degeneracy [2] and quantized non-abelian geometric phases of degenerate ground states. [1]
Residues of correlation functions in Liouville theory can also be computed, and this led to the original derivation of the DOZZ formula for the three-point structure constant. [12] [13] In the case of free bosons, the introduction of screening charges can be used for defining nontrivial CFTs including conformal Toda theory. The symmetries of ...
In lattice field theory, the Nielsen–Ninomiya theorem is a no-go theorem about placing chiral fermions on a lattice.In particular, under very general assumptions such as locality, hermiticity, and translational symmetry, any lattice formulation of chiral fermions necessarily leads to fermion doubling, where there are the same number of left-handed and right-handed fermions.