412,881 research outputs found
Faster Dynamic Range Mode
In the dynamic range mode problem, we are given a sequence a of length bounded by N and asked to support element insertion, deletion, and queries for the most frequent element of a contiguous subsequence of a. In this work, we devise a deterministic data structure that handles each operation in worst-case O?(N^0.655994) time, thus breaking the O(N^{2/3}) per-operation time barrier for this problem. The data structure is achieved by combining the ideas in Williams and Xu (SODA 2020) for batch range mode with a novel data structure variant of the Min-Plus product
Dynamic acousto-mechanical control of a strongly coupled photonic molecule
Two-dimensional photonic crystal membranes provide a versatile planar
architecture for integrated photonics to control the propagation of light on a
chip employing high quality optical cavities, waveguides, beamsplitters or
dispersive elements. When combined with highly non-linear quantum emitters,
quantum photonic networks operating at the single photon level come within
reach. Towards large-scale quantum photonic networks, selective dynamic control
of individual components and deterministic interactions between different
constituents are of paramount importance. This indeed calls for switching
speeds ultimately on the system's native timescales. For example, manipulation
via electric fields or all-optical means have been employed for switching in
nanophotonic circuits and cavity quantum electrodynamics studies. Here, we
demonstrate dynamic control of the coherent interaction between two coupled
photonic crystal nanocavities forming a photonic molecule. By using an
electrically generated radio frequency surface acoustic wave we achieve
optomechanical tuning, demonstrate operating speeds more than three orders of
magnitude faster than resonant mechanical approaches. Moreover, the tuning
range is large enough to compensate for the inherent fabrication-related cavity
mode detuning. Our findings open a route towards nanomechanically gated
protocols, which hitherto have inhibited the realization in all-optical
schemes.Comment: submitted manuscrip
Switch between critical percolation modes in city traffic dynamics
Percolation transition is widely observed in networks ranging from biology to
engineering. While much attention has been paid to network topologies, studies
rarely focus on critical percolation phenomena driven by network dynamics.
Using extensive real data, we study the critical percolation properties in city
traffic dynamics. Our results suggest that two modes of different critical
percolation behaviors are switching in the same network topology under
different traffic dynamics. One mode of city traffic (during nonrush hours or
days off) has similar critical percolation characteristics as small world
networks, while the other mode (during rush hours on working days) tends to
behave as a 2D lattice. This switching behavior can be understood by the fact
that the high-speed urban roads during nonrush hours or days off (that are
congested during rush hours) represent effective long-range connections, like
in small world networks. Our results might be useful for understanding and
improving traffic resilience.Comment: 8 pages, 4 figures, Daqing Li, Ziyou Gao and H. Eugene Stanley are
the corresponding authors ([email protected], [email protected],
[email protected]
Nanoscale surface relaxation of a membrane stack
Recent measurements of the short-wavelength (~ 1--100 nm) fluctuations in
stacks of lipid membranes have revealed two distinct relaxations: a fast one
(decay rate of ~ 0.1 ns^{-1}), which fits the known baroclinic mode of bulk
lamellar phases, and a slower one (~ 1--10 \mu s^{-1}) of unknown origin. We
show that the latter is accounted for by an overdamped capillary mode,
depending on the surface tension of the stack and its anisotropic viscosity. We
thereby demonstrate how the dynamic surface tension of membrane stacks could be
extracted from such measurements.Comment: 4 page
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