# name
Nonlocal exchange effects on the bulk plasmon dispersion relation

# metadata.dc.description.abstract[].value
Starting from the action principle, a bulk plasmon dispersion relation is obtained. We work with Slater determinants built of plane waves and consider a Hermitian generator of plasma oscillations (with well-defined q momentum) S=αQ-βP, where Q=
tsum
j
 cos(q⋅
x
j
) is a time-even Hermitian generator, P=scrB 
tsum
j
 [
p
j
⋅q sin(q⋅
x
j
)+sin(q⋅
x
j
)
p
j
⋅q] is a time-odd Hermitian generator, α(t) and β(t) are real time-dependent functions, and scrB is a real normalization constant. If the parameters α and β are small, the amplitude of the plasma oscillations generated by S is small. The quantum-mechanical action principle leads, in the harmonic approximation, to a quadratic Lagrangian 
L
(
2
)
(α,β) from which the dispersion relation is obtained. The nonlocal expression of the exchange contribution is explicitly obtained. The resulting bulk plasmon dispersion relation is related to the energy-weighted and cubic-energy-weighted sum rules. Finally, we compare our results with the experimental data.

# metadata.dc.relation.isformatof[].value
Reproducció digital del document publicat en format paper, proporcionada per PROLA i http://dx.doi.org/10.1103/PhysRevB.45.6935

# metadata.dc.source[].value
Articles publicats en revistes (Física Quàntica i Astrofísica)

# metadata.dc.title[].value
Nonlocal exchange effects on the bulk plasmon dispersion relation