Two interacting Hofstadter butterflies

Fractional quantum Hall effect in Hofstadter butterflies of Dirac fermions.

We report on the influence of a periodic potential on the fractional quantum Hall effect (FQHE) states in monolayer graphene. We have shown that for two values of the magnetic flux per unit cell (one-half and one-third flux quantum) an increase of the periodic potential strength results in a closure of the FQHE gap and appearance of gaps due to the periodic potential. In the case of one-half fl...

Hofstadter butterflies and magnetically induced band-gap quenching in graphene antidot lattices

Gap structure of the Hofstadter system of interacting Dirac fermions in graphene.

The effects of mutual Coulomb interactions between Dirac fermions in monolayer graphene on the Hofstadter energy spectrum are investigated. For two flux quanta per unit cell of the periodic potential, interactions open a gap in each Landau level with the smallest gap in the n=1 Landau level. For more flux quanta through the unit cell, where the noninteracting energy spectra have many gaps in ea...

Daily Activity Patterns of Two Co-Occurring Tropical Satyrine Butterflies

Adult males and females of many insect species are expected to adjust their daily activity pattern in order to avoid stressful climatic conditions and increase the chances to encounter sexual partners. Using scan sampling methods associated with focal individual observations it was found that two satyrine butterflies of similar size and morphology, Hermeuptychia hermes (Fabricius) (Leptidoptera...

Numerical results for two interacting

Much evidence has been collected to date which shows that repulsive electron-electron interaction can lead to the formation of particle pairs in a one-dimensional random energy landscape. The localization length 2 of these pair states is nite, but larger than the localization length 1 of the individual particles. After a short review of previous work, we present numerical evidence for this eeec...