Physics – Condensed Matter – Mesoscale and Nanoscale Physics
Scientific paper
2008-12-17
Eur. Phys. J. B 68, 183 (2009)
Physics
Condensed Matter
Mesoscale and Nanoscale Physics
22 pages, 5 figures
Scientific paper
10.1140/epjb/e2009-00087-5
By using the composite many-body theory for Frenkel excitons we have recently developed, we here derive the ground state energy of $N$ Frenkel excitons in the Born approximation through the Hamiltonian mean value in a state made of $N$ identical $\mathbf{Q=0}$ excitons. While this quantity reads as a density expansion in the case of Wannier excitons, due to many-body effects induced by fermion exchanges between $N$ composite particles, we show that the Hamiltonian mean value for $N$ Frenkel excitons only contains a first order term in density, just as for elementary bosons. Such a simple result comes from a subtle balance, difficult to guess a priori, between fermion exchanges for two or more Frenkel excitons appearing in Coulomb term and the ones appearing in the $N$ exciton normalization factor - the cancellation being exact within terms in $1/N_{s}$ where $N_{s}$ is the number of atomic sites in the sample. This result could make us naively believe that, due to the tight binding approximation on which Frenkel excitons are based, these excitons are just bare elementary bosons while their composite nature definitely appears at various stages in the precise calculation of the Hamiltonian mean value.
Combescot Monique
Pogosov Walter V.
No associations
LandOfFree
Ground state energy of N Frenkel excitons does not yet have a rating. At this time, there are no reviews or comments for this scientific paper.
If you have personal experience with Ground state energy of N Frenkel excitons, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Ground state energy of N Frenkel excitons will most certainly appreciate the feedback.
Profile ID: LFWR-SCP-O-94475