English (United Kingdom)

https://curated-unify.zendy.io/wp-json/zendy-region/v1/featured_content/oa?rat=en

https://curated-unify.zendy.io/wp-json/zendy-region/v1/highlighted_journal/

Global: Zendy Plus annual

Presents the access of premium content as premium feature

Premium Content

Presents the keyphrase highlighting as premium feature

Keyphrase Highlighting

Presents the summarisation as premium feature

Summarisation

Insights

Presents the pdf analysis as premium feature

PDF Analysis

Presents the zaia usage as premium feature

ZAIA

Global: Zendy Tools annual

Global: Zendy Free Plan

Global: Zendy Tools monthly

Global: Zendy Plus monthly

The ground state energy and energy gap to the first excited state arecalculated for the attractive Hubbard model in one dimension using both theBethe Ansatz equations and the variational BCS wavefunction. Comparisons areprovided as a function of coupling strength and electron density. While theground state energies are always in very good agreement, the BCS energy gap issometimes incorrect by an order of magnitude, particularly at half-filling.Finite size effects are also briefly discussed for cases where an exactsolution in the thermodynamic limit is not possible. In general, the BCS resultfor the energy gap is poor compared to the exact result.Comment: 25 pages, 5 Postscript figure

Evaluation of the BCS approximation for the attractive Hubbard model in one dimension