Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Fluctuations in extractable work bound the charging power of quantum
  batteries   We study the connection between the charging power of quantum batteries and
the fluctuations of the extractable work. We prove that in order to have a
non-zero rate of change of the extractable work, the state $\rho_\mathcal{W}$
of the battery cannot be an eigenstate of a `\emph{free energy operator}',
defined by
$\mathcal{F}~\equiv~H_\mathcal{W}~+~\beta^{-1}\log(\rho_\mathcal{W})$, where
$H_\mathcal{W}$ is the Hamiltonian of the battery and $\beta$ is the inverse
temperature of a reference thermal bath with respect to which the extractable
work is calculated. We do so by proving that fluctuations in the free energy
operator upper bound the charging power of a quantum battery. Our findings also
suggest that quantum coherence in the battery enhances the charging process,
which we illustrate on a toy model of a heat engine.
  \
  \emph{Note: this version includes our Reply to a Comment by Cusumano and
Rudnicki, both published in Phys. Rev. Lett.}

18
The categories of this paper are: econ
10
The categories of this paper are: q-bio
30
The categories of this paper are: q-alg
33
The categories of this paper are: plasm-ph
1
The categories of this paper are: cs
20
The categories of this paper are: acc-phys
21
The categories of this paper are: adap-org
31
The categories of this paper are: ao-sci
36
The categories of this paper are: cmp-lg
5
The categories of this paper are: gr-qc
27
The categories of this paper are: comp-gas
6
The categories of this paper are: astro-ph
16
The categories of this paper are: stat
25
The categories of this paper are: patt-sol
0
The categories of this paper are: hep-ph
15
The categories of this paper are: nucl-ex