Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Quantum walks of two correlated photons in a 2D synthetic lattice   Quantum walks represent paradigmatic quantum evolutions, enabling powerful
applications in the context of topological physics and quantum computation.
They have been implemented in diverse photonic architectures, but the
realization of a two-particle dynamics on a multi-dimensional lattice has
hitherto been limited to continuous-time evolutions. To fully exploit the
computational capabilities of quantum interference it is crucial to develop
platforms handling multiple photons that propagate across multi-dimensional
lattices. Here, we report a discrete-time quantum walk of two correlated
photons in a two-dimensional lattice, synthetically engineered by manipulating
a set of optical modes carrying quantized amounts of transverse momentum.
Mode-couplings are introduced via the polarization-controlled diffractive
action of thin geometric-phase optical elements. The entire platform is
compact, efficient, scalable, and represents a versatile tool to simulate
quantum evolutions on complex lattices. We expect that it will have a strong
impact on diverse fields such as quantum state engineering, topological quantum
photonics, and Boson Sampling.

8
The categories of this paper are: hep-ex
30
The categories of this paper are: q-alg
36
The categories of this paper are: cmp-lg
2
The categories of this paper are: math
16
The categories of this paper are: stat
29
The categories of this paper are: funct-an
19
The categories of this paper are: eess
20
The categories of this paper are: acc-phys
35
The categories of this paper are: mtrl-th
7
The categories of this paper are: hep-th
22
The categories of this paper are: chao-dyn
27
The categories of this paper are: comp-gas
9
The categories of this paper are: nlin
6
The categories of this paper are: astro-ph
11
The categories of this paper are: hep-lat
5
The categories of this paper are: gr-qc