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Weyl spinors are a solution to the Dirac equation derived by Hermann Weyl, called the Weyl equation. [3] For example, one-half of a charged Dirac fermion of a definite chirality is a Weyl fermion. [4] Weyl fermions may be realized as emergent quasiparticles in a low-energy condensed matter system.
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 physics, particularly in quantum field theory, the Weyl equation is a relativistic wave equation for describing massless spin-1/2 particles called Weyl fermions. The equation is named after Hermann Weyl. The Weyl fermions are one of the three possible types of elementary fermions, the other two being the Dirac and the Majorana fermions.
In condensed matter physics, a quasiparticle is a concept used to describe a collective behavior of a group of particles that can be treated as if they were a single particle. Formally, quasiparticles and collective excitations are closely related phenomena that arise when a microscopically complicated system such as a solid behaves as if it ...
The concept goes back to Majorana's suggestion in 1937 [2] that electrically neutral spin- 1 / 2 particles can be described by a real-valued wave equation (the Majorana equation), and would therefore be identical to their antiparticle, because the wave functions of particle and antiparticle are related by complex conjugation, which leaves the Majorana wave equation unchanged.
A chiral phenomenon is one that is not identical to its mirror image (see the article on mathematical chirality). The spin of a particle may be used to define a handedness , or helicity, for that particle, which, in the case of a massless particle, is the same as chirality.
While the Weyl equation was originally derived for odd spatial dimensions, the generalization of a 3D Weyl fermion state in 2D leads to a distinct topological state of matter, labeled as 2D Weyl semimetals. 2D Weyl semimetals are spin-polarized analogues of graphene that promise access to topological properties of Weyl fermions in (2+1)-dim ...
crystal lattice Phoniton: A theoretical quasiparticle which is a hybridization of a localized, long-living phonon and a matter excitation [15] phonon Phonon: Vibrational modes in a crystal lattice associated with atomic shifts crystal lattice Phonon polariton: A coupling between phonon and photons. optical phonon, photon Plasmariton