Europhys. Lett.
Volume 75, Number 5, September 2006
Page(s) 695 - 701
Section General
Published online 21 July 2006
Europhys. Lett., 75 (5), pp. 695-701 (2006)
DOI: 10.1209/epl/i2006-10165-x

Molecular signatures in the structure factor of an interacting Fermi gas

R. Combescot1, S. Giorgini2 and S. Stringari2

1  Laboratoire de Physique Statistique, Ecole Normale Supérieure 24 rue Lhomond, 75231 Paris Cedex 05, France
2  Dipartimento di Fisica, Università di Trento and CNR-INFM BEC Center I-38050 Povo, Trento, Italy

received 19 May 2006; accepted 4 July 2006
published online 21 July 2006

The static and dynamic structure factors of an interacting Fermi gas along the BCS-BEC crossover are calculated at momentum transfer $\hbar{\bm k}$ higher than the Fermi momentum. The spin structure factor is found to be very sensitive to the correlations associated with the formation of molecules. On the BEC side of the crossover, even close to unitarity, clear evidence is found for a molecular excitation at $\hbar^2 k^2 /4m$, where m is the atomic mass. Both quantum Monte Carlo and dynamic mean-field results are presented.

03.75.Hh - Static properties of condensates; thermodynamical, statistical, and structural properties.
03.75.Ss - Degenerate Fermi gases.
05.30.Fk - Fermion systems and electron gas.

© EDP Sciences 2006