Photons have negligible wave vectors and therefore the band extremes have to be in the same position of the Brillouin zone.
22.
The translational diffusion coefficient may be derived at a single angle or at a range of angles depending on the wave vector.
23.
In particular, if a finite wave vector is supposed to be the most unstable one, the Jacobian must have the signs
24.
One dimensional signals are expressed in terms of a single domain while multidimensional signals are represented in wave vector and frequency spectrum.
25.
A parallel beam, with wave vector \ mathbf { k } _ i is incident on a square lattice of parameter a.
26.
This early research included the relationship of the phase velocity to group velocity and the relationship of the wave vector and Pointing vector.
27.
Where F is the electric field, E ( k ) is the energy dispersion relation, and k is the momentum wave vector.
28.
Because the technique is sensitive to the angle of the emitted electrons one can determine the spectrum for different wave vectors on the Fermi surface.
29.
The z-averaged translational diffusion coefficient may be derived at a single angle or at a range of angles depending on the wave vector.
30.
Where " kc " } } and, } } are photon annihilation and creation operators for the mode with wave vector and polarization.
