26,269 research outputs found
Higher-order components dictate higher-order dynamics in hypergraphs
The presence of the giant component is a necessary condition for the
emergence of collective behavior in complex networked systems. Unlike networks,
hypergraphs have an important native feature that components of hypergraphs
might be of higher order, which could be defined in terms of the number of
common nodes shared between hyperedges. Although the extensive higher-order
component (HOC) could be witnessed ubiquitously in real-world hypergraphs, the
role of the giant HOC in collective behavior on hypergraphs has yet to be
elucidated. In this Letter, we demonstrate that the presence of the giant HOC
fundamentally alters the outbreak patterns of higher-order contagion dynamics
on real-world hypergraphs. Most crucially, the giant HOC is required for the
higher-order contagion to invade globally from a single seed. We confirm it by
using synthetic random hypergraphs containing adjustable and analytically
calculable giant HOC.Comment: Main: 6 pages, 4 figures. Supplementary Material: 7 pages, 7 figure
Suppression of Higgsino mediated proton decay by cancellations in GUTs and strings
A mechanism for the enhancement for proton lifetime in
supersymmetric/supergravity (SUSY/SUGRA) grand unified theories (GUTs) and in
string theory models is discussed where Higgsino mediated proton decay arising
from color triplets (anti-triplets) with charges and
is suppressed by an internal cancellation due to contributions
from different sources. We exhibit the mechanism for an SU(5) model with
Higgs multiplets in addition to the usual Higgs structure of
the minimal model. This model contains both and
Higgs color triplets (anti-triplets) and simple constraints allow for a
complete suppression of Higgsino mediated proton decay. Suppression of proton
decay in an SU(5) model with Planck scale contributions is also considered. The
suppression mechanism is then exhibited for an SO(10) model with a unified
Higgs structure involving representations.The SU(5)
decomposition of contains and
and the cancellation mechanism arises among these
contributions which mirrror the SU(5) case. The cancellation mechanism appears
to be more generally valid for a larger class of unification models.
Specifically the cancellation mechanism may play a role in string model
constructions to suppress proton decay from dimension five operators. The
mechanism allows for the suppression of proton decay consistent with current
data allowing for the possibility that proton decay may be visible in the next
round of nucleon stability experiment.Comment: 26 pages, no figures. Revtex 4. To appear in Physical Review
Scanning tunneling spectroscopic studies of the pairing state of cuprate superconductors
Quasiparticle tunneling spectra of both hole-doped (p-type) and electron-doped (n-type) cuprates are studied using a low-temperature scanning tunneling microscope. The results reveal that neither the pairing symmetry nor the pseudogap phenomenon is universal among all cuprates, and that the response of n-type cuprates to quantum impurities is drastically different from that of the p-type cuprates. The only ubiquitous features among all cuprates appear to be the strong electronic correlation and the nearest-neighbor antiferromagnetic Cu2+-Cu2+ coupling in the CuO2 planes
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