247 research outputs found
Infinite Matrix Product States for long range SU(N) spin models
We construct 1D and 2D long-range SU(N) spin models as parent Hamiltonians
associated with infinite matrix product states. The latter are constructed from
correlators of primary fields in the SU(N) level 1 WZW model. Since the
resulting groundstates are of Gutzwiller-Jastrow type, our models can be
regarded as lattice discretizations of fractional quantum Hall systems. We then
focus on two specific types of 1D spin chains with spins located on the unit
circle, a uniform and an alternating arrangement. For an equidistant
distribution of identical spins we establish an explicit connection to the
SU(N) Haldane-Shastry model, thereby proving that the model is critical and
described by a SU(N) level 1 WZW model. In contrast, while turning out to be
critical as well, the alternating model can only be treated numerically. Our
numerical results rely on a reformulation of the original problem in terms of
loop models.Comment: 37 pages, 6 figure
Task swapping networks in distributed systems
In this paper we propose task swapping networks for task reassignments by
using task swappings in distributed systems. Some classes of task reassignments
are achieved by using iterative local task swappings between software agents in
distributed systems. We use group-theoretic methods to find a minimum-length
sequence of adjacent task swappings needed from a source task assignment to a
target task assignment in a task swapping network of several well-known
topologies.Comment: This is a preprint of a paper whose final and definite form is
published in: Int. J. Comput. Math. 90 (2013), 2221-2243 (DOI:
10.1080/00207160.2013.772985
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