16,306 research outputs found
A Growing Self-Organizing Network for Reconstructing Curves and Surfaces
Self-organizing networks such as Neural Gas, Growing Neural Gas and many
others have been adopted in actual applications for both dimensionality
reduction and manifold learning. Typically, in these applications, the
structure of the adapted network yields a good estimate of the topology of the
unknown subspace from where the input data points are sampled. The approach
presented here takes a different perspective, namely by assuming that the input
space is a manifold of known dimension. In return, the new type of growing
self-organizing network presented gains the ability to adapt itself in way that
may guarantee the effective and stable recovery of the exact topological
structure of the input manifold
Sign-problem-free quantum Monte Carlo of the onset of antiferromagnetism in metals
The quantum theory of antiferromagnetism in metals is necessary for our
understanding of numerous intermetallic compounds of widespread interest. In
these systems, a quantum critical point emerges as external parameters (such as
chemical doping) are varied. Because of the strong coupling nature of this
critical point, and the "sign problem" plaguing numerical quantum Monte Carlo
(QMC) methods, its theoretical understanding is still incomplete. Here, we show
that the universal low-energy theory for the onset of antiferromagnetism in a
metal can be realized in lattice models, which are free from the sign problem
and hence can be simulated efficiently with QMC. Our simulations show Fermi
surface reconstruction and unconventional spin-singlet superconductivity across
the critical point.Comment: 17 pages, 4 figures; (v2) revised presentatio
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