414 research outputs found
New improvement to Falconer distance set problem in higher dimensions
We show that if a compact set has Hausdorff dimension
larger than , where , then
there is a point such that the pinned distance set has
positive Lebesgue measure. This improves upon bounds of Du-Zhang and
Du-Iosevich-Ou-Wang-Zhang in all dimensions . We also prove lower
bounds for Hausdorff dimension of pinned distance sets when , which improves upon bounds of Harris
and Wang-Zheng in dimensions .Comment: 36 page
Weighted refined decoupling estimates and application to Falconer distance set problem
We prove some weighted refined decoupling estimates. As an application, we
give an alternative proof of the following result on Falconer's distance set
problem by the authors in a companion work: if a compact set has Hausdorff dimension larger than
, where , then there is a
point such that the pinned distance set has positive
Lebesgue measure. Aside from this application, the weighted refined decoupling
estimates may be of independent interest.Comment: 28 pages. arXiv admin note: text overlap with arXiv:2309.0410
Ultrafast all-optical switching via coherent modulation of metamaterial absorption
We report on the demonstration of a femtosecond all-optical modulator
providing, without nonlinearity and therefore at arbitrarily low intensity,
ultrafast light-by-light control. The device engages the coherent interaction
of optical waves on a metamaterial nanostructure only 30 nm thick to
efficiently control absorption of near-infrared (750-1040 nm) femtosecond
pulses, providing switching contrast ratios approaching 3:1 with a modulation
bandwidth in excess of 2 THz. The functional paradigm illustrated here opens
the path to a family of novel meta-devices for ultra-fast optical data
processing in coherent networks.Comment: 5 pages, 4 figure
Intrinsic optical bistability in nanomechanical metamaterials at milliwatt power levels
We report the first demonstration of optical bistability in nanomechanical metamaterials - arrays of plasmonic or dielectric resonators on flexible nano-membranes. Bistability results from the nonlinearity of the near-field forces induced by light
Photonic Metamaterial Analogue of a Continuous Time Crystal
Time crystals are an eagerly sought phase of matter with broken
time-translation symmetry. Quantum time crystals with discretely broken
time-translation symmetry have been demonstrated in trapped ions, atoms and
spins while continuously broken time-translation symmetry has been observed in
an atomic condensate inside an optical cavity. Here we report that a classical
metamaterial nanostructure, a two-dimensional array of plasmonic metamolecules
supported on flexible nanowires, can be driven to a state possessing all of the
key features of a continuous time crystal: continuous coherent illumination by
light resonant with the metamolecules' plasmonic mode triggers a spontaneous
phase transition to a superradiant-like state of transmissivity oscillations,
resulting from many-body interactions among the metamolecules, characterized by
long-range order in space and time. The phenomenon is of interest to the study
of dynamic classical many-body states in the strongly correlated regime and
applications in all-optical modulation, frequency conversion and timing.Comment: 10 pages, 6 figure
Puzzling subunits of mitochondrial cytochrome reductase
The ubiquinol-cytochrome c reductase complex, like the other proton-pumping respiratory complexes of mitochondria, is an assembly of many different subunits. However, only a few of these subunits participate directly in the electron transfer and proton translocation. The roles of the other subunits are largely unknown. We discuss here some intriguing features of two of these subunits
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