Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Sequential feedback scheme outperforms the parallel scheme for
  Hamiltonian parameter estimation   Measurement and estimation of parameters are essential for science and
engineering, where the main quest is to find out the highest achievable
precision with given resources and design schemes to attain it. Two schemes,
the sequential feedback scheme and the parallel scheme, are usually studied in
quantum parameter estimation. While the sequential feedback scheme represents
the most general scheme, it remains unknown whether it can outperform the
parallel scheme for any quantum estimation tasks. In this Letter we show that
the sequential feedback scheme has a 3-fold improvement over the parallel
scheme for Hamiltonian parameter estimations on 2-dimensional systems, and an
order of $O(d+1)$ improvement for Hamiltonian parameter estimation on
$d-$dimensional systems. We also show that, contrary to the conventional
belief, it is possible to simultaneously achieve the highest precision for
estimating all three components of a magnetic field, which sets a benchmark on
the local precision limit for the estimation of a magnetic field.

27
The categories of this paper are: comp-gas
4
The categories of this paper are: cond-mat
8
The categories of this paper are: hep-ex
22
The categories of this paper are: chao-dyn
33
The categories of this paper are: plasm-ph
25
The categories of this paper are: patt-sol
19
The categories of this paper are: eess
11
The categories of this paper are: hep-lat
37
The categories of this paper are: supr-con
31
The categories of this paper are: ao-sci
1
The categories of this paper are: cs
15
The categories of this paper are: nucl-ex
7
The categories of this paper are: hep-th
23
The categories of this paper are: solv-int
34
The categories of this paper are: chem-ph
0
The categories of this paper are: hep-ph