Symbol  Meaning 
set of real numbers 

norm of the argument 

modulus of the argument 

Landau symbol 

unit sphere 

colatitude (polar angle) 

longitude (azimuth) 

unit sphere surface element, 

,  unit vectors w.r.t. and 
Nabla operator 

Laplace operator 

matrices (capital letters, bold) 

vectors (lowercase, bold) 

real valued spherical harmonic of major index and minor index 

spherical harmonics expansion coefficient to of the quantity 

Kronecker delta 

delta distribution 

triangulation of the simulation domain 

Voronoi box grid of 

a box from the adjoint box grid 

dual box grid of 

a box from the box grid overlapping and 

interface area between boxes and 

volume fraction of the boxes and associated with 

surface unit normal vector of box pointing into 

number of degrees of freedom in space 

number of degrees of freedom in space 

number of discrete total energies 

spherical harmonics expansion order 

Symbol  Meaning 
Planck constant divided by 

Boltzmann constant 

permittivity (not to be confused with kinetic energy ) 

space charge 

elementary charge 

charge of a carrier (negative for electrons, positive for holes) 

effective mass 

kinetic energy (not to be confused with permittivity ) 

total energy 

time  
spatial coordinate within the device 

wave vector  
momentum vector 

(group) velocity 

force  
electric field 

quasielectrostatic potential 

scattering operator 

inscattering operator 

outscattering operator 

velocityrandomizing scattering operator 

index of the scattering process 

scattering coefficient 

symmetric scattering coefficient 

particle density (electron density) 

generalized density of states 

moment of the BTE with respect to the argument 

distribution function 

generalized energy distribution function 

generalized current density term 

spherical harmonics coupling term 

thermal voltage 

BTE  Boltzmann transport equation 
CPU  central processing unit 
GPU  graphics processing unit 
FET  field effect transistor 
MEDS  maximum entropy dissipation scheme 
MOSFET  metaloxidesemiconductor field effect transistor 
SHE  spherical harmonics expansion 
TCAD  technology computer aided design 