Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Finite-system effects on high-harmonic generation: from atoms to solids   Using time-dependent density functional theory, high-harmonic generation
(HHG) is studied in one-dimensional structures of sizes from a single nucleus
up to hundreds of nuclei. The HHG cutoff is observed to extent linearly with
the system size from the well known atomic HHG cutoff and is found to converge
into the previously observed cutoffs for bulk solids only for large systems. A
change in the response from that of single atoms or small molecules is observed
from system sizes of $N$ $\approx$ 6 nuclei and becomes independent of system
size at $N \gtrsim 60$. The system-size dependence of the observed HHG cutoffs
is found to follow the limitations, set by the finite size solid, on the
classical motion of electron-hole pairs. Because of the relation between
recombination energy and electron-hole propagation length in the system,
high-energy recombination events are not possible in small systems but become
accessible for larger systems resulting in the change of the cutoff energies
with system size. When varying the field intensity we observe that the cutoffs
move linearly with the intensity even for small systems of $N\gtrsim 6$ that
are far from the limit of a bulk solid.

32
The categories of this paper are: atom-ph
26
The categories of this paper are: bayes-an
33
The categories of this paper are: plasm-ph
36
The categories of this paper are: cmp-lg
37
The categories of this paper are: supr-con
31
The categories of this paper are: ao-sci
35
The categories of this paper are: mtrl-th
17
The categories of this paper are: q-fin
18
The categories of this paper are: econ
30
The categories of this paper are: q-alg
0
The categories of this paper are: hep-ph
23
The categories of this paper are: solv-int
13
The categories of this paper are: quant-ph
12
The categories of this paper are: nucl-th
10
The categories of this paper are: q-bio
19
The categories of this paper are: eess