Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Parameter-free quantum hydrodynamic theory for plasmonics: Electron
  density-dependent damping rate and diffusion coefficient   Plasmonics is a rapid growing field, which has enabled both fundamental
science and inventions of various quantum optoelectronic devices. An accurate
and efficient method to calculate the optical response of metallic structures
with feature size in the nanoscale plays an important role. Quantum
hydrodynamic theory (QHT) provides an efficient description of the
free-electron gas, where quantum effects of nonlocality and spill-out are taken
into account. In this work, we introduce a general QHT that includes diffusion
to account for the broadening, which is a key problem in practical applications
of surface plasmon. We will introduce a density-dependent diffusion coefficient
to give very accurate linewidth. It is a self-consistent method, in which both
the ground and excited states are solved by using the same energy functional,
with the kinetic energy described by the Thomas-Fermi and von Weizs\"{a}cker
(vW) formalisms. In addition, our QHT method is stable by introduction of an
electron density-dependent damping rate. For sodium nanosphere of various
sizes, the plasmon energy and broadening by our QHT method are in excellent
agreement with those by density functional theory and Kreibig formula. By
applying our QHT method to sodium jellium nanorods, we clearly show that our
method enables a parameter-free simulation, i.e. without resorting to any
empirical parameter, such as size-dependent damping rate and diffusing
coefficient. It is found that there exists a perfect linear relation between
the resonance wavelength and aspect radio. The width decreases with increasing
aspect ratio and height. The calculations show that our QHT method provides an
explicit and unified way to account for size-dependent frequency shifts and
broadening of arbitrarily shaped geometries. It is reliable and robust with
great predicability, and hence provides a general and efficient platform to
study plasmonics.

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The categories of this paper are: dg-ga
33
The categories of this paper are: plasm-ph
19
The categories of this paper are: eess
12
The categories of this paper are: nucl-th
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The categories of this paper are: comp-gas
5
The categories of this paper are: gr-qc
25
The categories of this paper are: patt-sol
1
The categories of this paper are: cs
10
The categories of this paper are: q-bio
15
The categories of this paper are: nucl-ex
9
The categories of this paper are: nlin
30
The categories of this paper are: q-alg
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The categories of this paper are: mtrl-th
8
The categories of this paper are: hep-ex
20
The categories of this paper are: acc-phys
26
The categories of this paper are: bayes-an