4,762 research outputs found
Gluon quasidistribution function at one loop
We study the unpolarized gluon quasidistribution function in the nucleon at
one loop level in the large momentum effective theory. For the quark
quasidistribution, power law ultraviolet divergences arise in the cut-off
scheme and an important observation is that they all are subjected to Wilson
lines. However for the gluon quasidistribution function, we first point out
that the linear ultraviolet divergences also exist in the real diagram which is
not connected to any Wilson line. We then study the one loop corrections to
parton distribution functions in both cut-off scheme and dimensional
regularization to deal with the ultraviolet divergences. In addition to the
ordinary quark and gluon distributions, we also include the quark to gluon and
gluon to quark splitting diagrams. The complete one-loop matching factors
between the quasi and light cone parton distribution functions are presented in
the cut-off scheme. We derive the evolution equation for quasi parton
distribution functions, and find that the evolution kernels are identical
to the DGLAP evolution kernels.Comment: 26 pages,8 figures;accepted by Eur.Phys.J
Two-hole ground state wavefunction: Non-BCS pairing in a - two-leg ladder system
Superconductivity is usually described in the framework of the
Bardeen-Cooper-Schrieffer (BCS) wavefunction, which even includes the
resonating-valence-bond (RVB) wavefunction proposed for the high-temperature
superconductivity in the cuprate. A natural question is \emph{if} any
fundamental physics could be possibly missed by applying such a scheme to
strongly correlated systems. Here we study the pairing wavefunction of two
holes injected into a Mott insulator/antiferromagnet in a two-leg ladder using
variational Monte Carlo (VMC) approach. By comparing with density matrix
renormalization group (DMRG) calculation, we show that a conventional BCS or
RVB pairing of the doped holes makes qualitatively wrong predictions and is
incompatible with the fundamental pairing force in the - model, which is
kinetic-energy-driven by nature. By contrast, a non-BCS-like wavefunction
incorporating such novel effect will result in a substantially enhanced pairing
strength and improved ground state energy as compared to the DMRG results. We
argue that the non-BCS form of such a new ground state wavefunction is
essential to describe a doped Mott antiferromagnet at finite doping.Comment: 11 pages, 5 figure
GPSP: Graph Partition and Space Projection based Approach for Heterogeneous Network Embedding
In this paper, we propose GPSP, a novel Graph Partition and Space Projection
based approach, to learn the representation of a heterogeneous network that
consists of multiple types of nodes and links. Concretely, we first partition
the heterogeneous network into homogeneous and bipartite subnetworks. Then, the
projective relations hidden in bipartite subnetworks are extracted by learning
the projective embedding vectors. Finally, we concatenate the projective
vectors from bipartite subnetworks with the ones learned from homogeneous
subnetworks to form the final representation of the heterogeneous network.
Extensive experiments are conducted on a real-life dataset. The results
demonstrate that GPSP outperforms the state-of-the-art baselines in two key
network mining tasks: node classification and clustering.Comment: WWW 2018 Poste
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