26,064 research outputs found

    Higher-order components dictate higher-order dynamics in hypergraphs

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    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

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    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 Q=βˆ’1/3(1/3)Q=-1/3(1/3) and Q=βˆ’4/3(4/3)Q=-4/3(4/3) is suppressed by an internal cancellation due to contributions from different sources. We exhibit the mechanism for an SU(5) model with 45H+45Λ‰H45_H+\bar{45}_H Higgs multiplets in addition to the usual Higgs structure of the minimal model. This model contains both Q=βˆ’1/3(1/3)Q=-1/3(1/3) and Q=βˆ’4/3(4/3)Q=-4/3(4/3) 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 144H+144Λ‰H144_H+\bar{144}_H representations.The SU(5) decomposition of 144H+144Λ‰H144_H+\bar{144}_H contains 5H+5Λ‰H5_H+\bar 5_H and 45H+45Λ‰H45_H+\bar{45}_H 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

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    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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