Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Ultrafast dynamics of spin and orbital correlations in quantum
  materials: an energy- and momentum-resolved perspective   Many remarkable properties of quantum materials emerge from states with
intricate coupling between the charge, spin and orbital degrees of freedom.
Ultrafast photo-excitations of these materials hold great promise for
understanding and controlling the properties of these states. Here we introduce
time-resolved resonant inelastic X-ray scattering (trRIXS) as a means of
measuring charge, spin and orbital excitations out of equilibrium. These
excitations encode the correlations and interactions that determine the
detailed properties of the states generated. After outlining the basic
principles and instrumentation of tr-RIXS, we review our first observations of
transient antiferromagnetic correlations in quasi-two dimensions in a
photo-excited Mott insulator and present possible future routes of this
fast-developing technique. The increasing number of X-ray free electron laser
facilities not only enables tackling long-standing fundamental scientific
problems, but also promises to unleash novel inelastic X-ray scattering
spectroscopies

11
The categories of this paper are: hep-lat
29
The categories of this paper are: funct-an
3
The categories of this paper are: physics
14
The categories of this paper are: math-ph
34
The categories of this paper are: chem-ph
22
The categories of this paper are: chao-dyn
27
The categories of this paper are: comp-gas
18
The categories of this paper are: econ
16
The categories of this paper are: stat
5
The categories of this paper are: gr-qc
21
The categories of this paper are: adap-org
17
The categories of this paper are: q-fin
32
The categories of this paper are: atom-ph
8
The categories of this paper are: hep-ex
7
The categories of this paper are: hep-th
13
The categories of this paper are: quant-ph