Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Resolving continua of fractional excitations by spinon echo in THz 2D
  coherent spectroscopy   We show that the new technique of terahertz 2D coherent spectroscopy is
capable of giving qualitatively new information about fractionalized spin
systems. For the prototypical example of the transverse field Ising chain, we
demonstrate theoretically that, despite the broad continuum of excitations in
linear response, the 2D spectrum contains sharp features that are a coherent
signature of a `spinon echo', which gives previously inaccessible information
such as the lifetime of the two-spinon excited state. The effects of disorder
and finite lifetime, which are practically indistinguishable in the linear
optical or neutron response, manifest in dramatically different fashion in the
2D spectra. Our results may be directly applicable to model quasi-1D transverse
field Ising chain systems such as CoNb$_2$O$_6$, but the concept can be applied
to fractionalized spin systems in general.

27
The categories of this paper are: comp-gas
9
The categories of this paper are: nlin
29
The categories of this paper are: funct-an
2
The categories of this paper are: math
32
The categories of this paper are: atom-ph
21
The categories of this paper are: adap-org
34
The categories of this paper are: chem-ph
10
The categories of this paper are: q-bio
0
The categories of this paper are: hep-ph
22
The categories of this paper are: chao-dyn
17
The categories of this paper are: q-fin
36
The categories of this paper are: cmp-lg
13
The categories of this paper are: quant-ph
15
The categories of this paper are: nucl-ex
37
The categories of this paper are: supr-con
14
The categories of this paper are: math-ph