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A Weyl semimetal is a solid state crystal whose low energy excitations are Weyl fermions that carry electrical charge even at room temperatures. [ 11 ] [ 12 ] [ 13 ] A Weyl semimetal enables realization of Weyl fermions in electronic systems. [ 9 ]
All its fermions are chiral Weyl fermions, which means that the charged weak gauge bosons W + and W − only couple to left-handed quarks and leptons. [ d ] Some theorists found this objectionable, and so conjectured a GUT extension of the weak force which has new, high energy W′ and Z′ bosons , which do couple with right handed quarks and ...
Indices which have hats are called Dirac indices, and are the set of dotted and undotted, or chiral and anti-chiral, indices. For example, if =,, ˙ = ˙, ˙ then a spinor in the chiral basis is represented as
A phonon is a collective excitation in a periodic, elastic arrangement of atoms or molecules in condensed matter, specifically in solids and some liquids.In the context of optically trapped objects, the quantized vibration mode can be defined as phonons as long as the modal wavelength of the oscillation is smaller than the size of the object.
In quantum field theory, a chiral gauge theory is a quantum field theory with charged chiral (i.e. Weyl) fermions. For instance, the Standard Model is a chiral gauge theory. For topological reasons, chiral charged fermions cannot be given a mass without breaking the gauge symmetry, which will lead to inconsistencies unlike a global symmetry.
A chiral molecule is a type of molecule that has a non-superposable mirror image. The feature that is most often the cause of chirality in molecules is the presence of an asymmetric carbon atom. [16] [17] The term "chiral" in general is used to describe the object that is non-superposable on its mirror image. [18]
The three first are Type-I Weyl semimetals, the last one is a Type-II Weyl semimetal. In quantum mechanics , Dirac cones are a kind of crossing-point which electrons avoid , [ 8 ] where the energy of the valence and conduction bands are not equal anywhere in two dimensional lattice k -space , except at the zero dimensional Dirac points.
An acoustic metamaterial, sonic crystal, or phononic crystal is a material designed to manipulate sound waves or phonons in gases, liquids, and solids (crystal lattices).By carefully controlling properties such as the bulk modulus β, density ρ, and chirality, these materials can be tailored to interact with sound in specific ways, such as transmitting, trapping, or amplifying waves at ...