Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Atom phase controlled noise-free photon echoes   Rephasing in photon echoes is a fundamental mechanism of retrieving optical
information stored in a collective ensemble of atoms or ions. With an extremely
weak quantum optical data, population inversion by the rephasing process is
inevitable resulting in serious quantum noise. Here, an inversion-free
rephasing method in photon echoes is presented by using deshelving-based atom
phase control. The present method makes photon echoes directly applicable to
quantum memories with benefits of extended photon storage time and nearly
perfect retrieval efficiency. In this revised version only the rephasing pulse
propagation direction is corrected to make a silent echo of E1 in Fig. 1.

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The categories of this paper are: cmp-lg
3
The categories of this paper are: physics
18
The categories of this paper are: econ
5
The categories of this paper are: gr-qc
34
The categories of this paper are: chem-ph
1
The categories of this paper are: cs
29
The categories of this paper are: funct-an
24
The categories of this paper are: dg-ga
2
The categories of this paper are: math
4
The categories of this paper are: cond-mat
14
The categories of this paper are: math-ph
23
The categories of this paper are: solv-int
33
The categories of this paper are: plasm-ph
31
The categories of this paper are: ao-sci
20
The categories of this paper are: acc-phys
0
The categories of this paper are: hep-ph