Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Quantum probes for the cutoff frequency of Ohmic environments   Quantum probing consists of suitably exploiting a simple, small, and
controllable quantum system to characterize a larger and more complex system.
Here, we address the estimation of the cutoff frequency of the Ohmic spectral
density of a harmonic reservoir by quantum probes. To this aim, we address the
use of single-qubit and two-qubit systems and different kinds of coupling with
the bath of oscillators. We assess the estimation precision by the quantum
Fisher information of the sole quantum probe as well as the corresponding
quantum signal-to-noise ratio. We prove that, for most of the values of the
Ohmicity parameter, a simple probe such as a single qubit is already optimal
for the precise estimation of the cutoff frequency. Indeed for those values,
upon considering a two-qubit probe either in a Bell or in separable state, we
do not find improvement to the estimation precision. However, we also showed
that there exist few conditions where employing two qubits in a Bell state
interacting with a common bath is more suitable for precisely estimating the
cutoff frequency.

8
The categories of this paper are: hep-ex
1
The categories of this paper are: cs
2
The categories of this paper are: math
21
The categories of this paper are: adap-org
30
The categories of this paper are: q-alg
5
The categories of this paper are: gr-qc
18
The categories of this paper are: econ
14
The categories of this paper are: math-ph
34
The categories of this paper are: chem-ph
29
The categories of this paper are: funct-an
22
The categories of this paper are: chao-dyn
17
The categories of this paper are: q-fin
15
The categories of this paper are: nucl-ex
23
The categories of this paper are: solv-int
36
The categories of this paper are: cmp-lg
9
The categories of this paper are: nlin