Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Bipedal nanowalker by pure physical mechanisms   Artificial nanowalkers are inspired by biomolecular counterparts from living
cells, but remain far from comparable to the latter in design principles. The
walkers reported to date mostly rely on chemical mechanisms to gain a
direction; they all produce chemical wastes. Here we report a light-powered DNA
bipedal walker based on a design principle derived from cellular walkers. The
walker has two identical feet and the track has equal binding sites; yet the
walker gains a direction by pure physical mechanisms that autonomously amplify
an intra-site asymmetry into a ratchet effect. The nanowalker is free of any
chemical waste. It has a distinct thermodynamic feature that it possesses the
same equilibrium before and after operation, but generates a truly
non-equilibrium distribution during operation. The demonstrated design
principle exploits mechanical effects and is adaptable for use in other
nanomachines.

35
The categories of this paper are: mtrl-th
5
The categories of this paper are: gr-qc
1
The categories of this paper are: cs
30
The categories of this paper are: q-alg
17
The categories of this paper are: q-fin
27
The categories of this paper are: comp-gas
13
The categories of this paper are: quant-ph
18
The categories of this paper are: econ
7
The categories of this paper are: hep-th
9
The categories of this paper are: nlin
15
The categories of this paper are: nucl-ex
2
The categories of this paper are: math
32
The categories of this paper are: atom-ph
20
The categories of this paper are: acc-phys
29
The categories of this paper are: funct-an
8
The categories of this paper are: hep-ex