Non-Kosterlitz-Thouless transitions for the q-state clock models
2010 (English)In: Physical Review E. Statistical, Nonlinear, and Soft Matter Physics, ISSN 1063-651X, E-ISSN 1095-3787, Vol. 82, no 3, 031102- p.Article in journal (Refereed) Published
The $q$-state clock model with the cosine potential has a single phasetransition for $q\leq4$ and two transitions for $q\geq5$. It is shown byMonteCarlo simulations that the helicity modulus for the five-state clock model($q=5$) does not vanish at the high-temperature transition. This is incontrast to the clock models with $q\geq6$ for which the helicity modulusvanishes. This means that the transition for the five-state clock modeldiffers from the Kosterlitz-Thouless (KT) transition. It is also shown thatthis change in the transition is caused by an interplay between the numberof angular directions and the interaction potential: by slightly modifyingthe interaction potential, the KT transition for $q=6$ turns into the samenon-KT transition. Likewise, the KT transition is recovered for $q=5$ whenthe Villain potential is used. Comparisons with other clock-model resultsare made and discussed.
Place, publisher, year, edition, pages
2010. Vol. 82, no 3, 031102- p.
clock model, Kosterlitz-Thouless transition, Villain approximation
Other Physics Topics
Research subject Theoretical Physics
IdentifiersURN: urn:nbn:se:umu:diva-35750DOI: 10.1103/PhysRevE.82.031102ISI: 000281451700004OAI: oai:DiVA.org:umu-35750DiVA: diva2:346727