Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: QED Vacuum Loops and Dark Energy   A QED--based "bootstrap" mechanism is suggested as an explanation for the
vacuum energy that furnished the initial impulse for Inflation, and continues
on to provide present day Dark Energy. Virtual vacuum fluctuations are assumed
to generate effective electromagnetic fields whose average value corresponds to
an effective c--number $A_{\mu}^{\rm vac}(x)$, which is itself equal to the
vacuum expectation value of the operator $A_{\mu}(x)$ in the presence of that
$A_{\mu}^{\rm vac}(x)$. Lorentz invariance is manifest, as every observer would
measure the same electric field in his or her own reference frame. The model
has one arbitrary parameter $\xi$, and fits the energy density of present day
Dark Energy for $\xi\sim O(1)$.

23
The categories of this paper are: solv-int
3
The categories of this paper are: physics
32
The categories of this paper are: atom-ph
15
The categories of this paper are: nucl-ex
18
The categories of this paper are: econ
29
The categories of this paper are: funct-an
34
The categories of this paper are: chem-ph
35
The categories of this paper are: mtrl-th
26
The categories of this paper are: bayes-an
14
The categories of this paper are: math-ph
10
The categories of this paper are: q-bio
5
The categories of this paper are: gr-qc
31
The categories of this paper are: ao-sci
27
The categories of this paper are: comp-gas
19
The categories of this paper are: eess
25
The categories of this paper are: patt-sol