Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Observation of nonreciprocal wave propagation in a dynamic phononic
  lattice   Acoustic waves in a linear time-invariant medium are generally reciprocal;
however, reciprocity can break down in a time-variant system. In this Letter,
we report on an experimental demonstration of nonreciprocity in a dynamic
one-dimensional phononic crystal, where the local elastic properties are
dependent on time. The system consists of an array of repelling magnets, and
the on-site elastic potentials of the constitutive elements are modulated by an
array of electromagnets. The modulation in time breaks time-reversal symmetry
and opens a directional band gap in the dispersion relation. As shown by
experimental and numerical results, nonreciprocal mechanical systems like the
one presented here offer opportunities to create phononic diodes that can serve
for rectification applications.

22
The categories of this paper are: chao-dyn
35
The categories of this paper are: mtrl-th
34
The categories of this paper are: chem-ph
5
The categories of this paper are: gr-qc
16
The categories of this paper are: stat
1
The categories of this paper are: cs
2
The categories of this paper are: math
23
The categories of this paper are: solv-int
15
The categories of this paper are: nucl-ex
29
The categories of this paper are: funct-an
13
The categories of this paper are: quant-ph
14
The categories of this paper are: math-ph
33
The categories of this paper are: plasm-ph
36
The categories of this paper are: cmp-lg
9
The categories of this paper are: nlin
25
The categories of this paper are: patt-sol