Home

About

Advanced Search

Browse by Discipline

Scientific Societies

E-print Alerts

Add E-prints

E-print Network
FAQHELPSITE MAPCONTACT US


  Advanced Search  

 
Pairing fluctuations and pseudogaps in the attractive Hubbard model and A.-M. S. Tremblay1,2
 

Summary: Pairing fluctuations and pseudogaps in the attractive Hubbard model
B. Kyung,1
S. Allen,1
and A.-M. S. Tremblay1,2
1
De´partement de Physique and Centre de Recherche sur les Proprie´te´s E´lectroniques de Mate´riaux Avance´s,
Universite´ de Sherbrooke, Sherbrooke, Que´bec, Canada J1K 2R1
2
Institut Canadien de Recherches Avance´es, Universite´ de Sherbrooke, Sherbrooke, Que´bec, Canada J1K 2R1
Received 2 October 2000; revised manuscript received 2 March 2001; published 31 July 2001
The two-dimensional attractive Hubbard model is studied in the weak-to-intermediate-coupling regime by
employing a nonperturbative approach. It is shown that this approach is in quantitative agreement with Monte
Carlo calculations for both single-particle and two-particle quantities. Both the density of states and the
single-particle spectral weight show a pseudogap at the Fermi energy below some characteristic temperature
T*, also in good agreement with quantum Monte Carlo calculations. The pseudogap is caused by critical
pairing fluctuations in the low-temperature renormalized classical regime ( kBT) of the two-dimensional
system. With increasing temperature the spectral weight fills in the pseudogap instead of closing it, and the
pseudogap appears earlier in the density of states than in the spectral function. Small temperature changes
around T* can modify the spectral weight over frequency scales much larger than temperature. Several
qualitative results for the s-wave case should remain true for d-wave superconductors.

  

Source: Ahlers, Guenter - Department of Physics, University of California at Santa Barbara

 

Collections: Physics