130 research outputs found
Synthetic gauge fields enable high-order topology on Brillouin real projective plane
The topology of the Brillouin zone, foundational in topological physics, is
always assumed to be a torus. We theoretically report the construction of
Brillouin real projective plane () and the appearance of
quadrupole insulating phase, which are enabled by momentum-space nonsymmorphic
symmetries stemming from synthetic gauge fields. We show that
the momentum-space nonsymmorphic symmetries quantize bulk polarization and
Wannier-sector polarization nonlocally across different momenta, resulting in
quantized corner charges and an isotropic binary bulk quadrupole phase diagram,
where the phase transition is triggered by a bulk energy gap closing. Under
open boundary conditions, the nontrivial bulk quadrupole phase manifests either
trivial or nontrivial edge polarization, resulting from the violation of
momentum-space nonsymmorphic symmetries under lattice termination. We present a
concrete design for the quadrupole insulator based on acoustic
resonator arrays and discuss its feasibility in optics, mechanics, and
electrical circuits. Our results show that deforming the Brillouin manifold
creates opportunities for realizing high-order band topology.Comment: 5 pages,5 figure
Physical essence of propagable fractional-strength optical vortices in free space
Fractional-order vector vortex beams are recently demonstrated to be new
carriers of fractional-strength optical vortices. However, why can those new
vortex beams formed by the combination of both unstable states propagate stably
in free space? Here, we solve this scientific problem by revealing the physical
essence of propagable fractional-strength optical vortices in free space.Three
new understandings regarding those peculiar vortex beams are therefore
proposed, namely Abbe diffraction limit, phase evolution of vortex beam, and
phase binary time vector property.For the first one, owing to Abbe diffraction
limit, the inherent polarization modes are intertwined together, thereby
maintaining the entire peculiar vortex beams in free space. For the second one,
we demonstrate the phase evolution of vortex beam, which is the physical reason
of polarization rotation of fractional-order VVBs. For the third one, the phase
is not merely a scalar attribute of light beam, but manifests a binary time
vector property. This work provides entirely different physical viewpoints on
the phase of vortex beam and Abbe diffraction limit, which may deepen our
knowledge on the behavior of light beam in classical optics
Characterising User Transfer Amid Industrial Resource Variation: A Bayesian Nonparametric Approach
In a multitude of industrial fields, a key objective entails optimising
resource management whilst satisfying user requirements. Resource management by
industrial practitioners can result in a passive transfer of user loads across
resource providers, a phenomenon whose accurate characterisation is both
challenging and crucial. This research reveals the existence of user clusters,
which capture macro-level user transfer patterns amid resource variation. We
then propose CLUSTER, an interpretable hierarchical Bayesian nonparametric
model capable of automating cluster identification, and thereby predicting user
transfer in response to resource variation. Furthermore, CLUSTER facilitates
uncertainty quantification for further reliable decision-making. Our method
enables privacy protection by functioning independently of personally
identifiable information. Experiments with simulated and real-world data from
the communications industry reveal a pronounced alignment between prediction
results and empirical observations across a spectrum of resource management
scenarios. This research establishes a solid groundwork for advancing resource
management strategy development
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