Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Higher-order and fractional discrete time crystals in clean long-range
  interacting systems   Discrete time crystals are periodically driven systems characterized by a
response with periodicity $nT$, with $T$ the period of the drive and $n>1$.
Typically, $n$ is an integer and bounded from above by the dimension of the
local (or single particle) Hilbert space, the most prominent example being
spin-$1/2$ systems with $n$ restricted to $2$. Here we show that a clean
spin-$1/2$ system in the presence of long-range interactions and transverse
field can sustain a huge variety of different `higher-order' discrete time
crystals with integer and, surprisingly, even fractional $n > 2$. We
characterize these (arguably prethermal) non-equilibrium phases of matter
thoroughly using a combination of exact diagonalization, semiclassical methods,
and spin-wave approximations, which enable us to establish their stability in
the presence of competing long- and short-range interactions. Remarkably, these
phases emerge in a model with continous driving and time-independent
interactions, convenient for experimental implementations with ultracold atoms
or trapped ions.

29
The categories of this paper are: funct-an
24
The categories of this paper are: dg-ga
6
The categories of this paper are: astro-ph
5
The categories of this paper are: gr-qc
3
The categories of this paper are: physics
37
The categories of this paper are: supr-con
0
The categories of this paper are: hep-ph
20
The categories of this paper are: acc-phys
26
The categories of this paper are: bayes-an
27
The categories of this paper are: comp-gas
21
The categories of this paper are: adap-org
34
The categories of this paper are: chem-ph
7
The categories of this paper are: hep-th
15
The categories of this paper are: nucl-ex
25
The categories of this paper are: patt-sol
1
The categories of this paper are: cs