Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Dynamical Quantum Memories   We propose a dynamical approach to quantum memories using an
oscillator-cavity model. This overcomes the known difficulties of achieving
high quantum input-output fidelity with storage times long compared to the
input signal duration. We use a generic model of the memory response, which is
applicable to any linear storage medium ranging from a superconducting device
to an atomic medium. The temporal switching or gating of the device may either
be through a control field changing the coupling, or through a variable
detuning approach, as in more recent quantum memory experiments. An exact
calculation of the temporal memory response to an external input is carried
out. This shows that there is a mode-matching criterion which determines the
optimum input and output mode shape. This optimum pulse shape can be modified
by changing the gate characteristics. In addition, there is a critical coupling
between the atoms and the cavity that allows high fidelity in the presence of
long storage times. The quantum fidelity is calculated both for the coherent
state protocol, and for a completely arbitrary input state with a bounded total
photon number. We show how a dynamical quantum memory can surpass the relevant
classical memory bound, while retaining a relatively long storage time.

12
The categories of this paper are: nucl-th
36
The categories of this paper are: cmp-lg
14
The categories of this paper are: math-ph
24
The categories of this paper are: dg-ga
34
The categories of this paper are: chem-ph
2
The categories of this paper are: math
4
The categories of this paper are: cond-mat
8
The categories of this paper are: hep-ex
11
The categories of this paper are: hep-lat
6
The categories of this paper are: astro-ph
30
The categories of this paper are: q-alg
0
The categories of this paper are: hep-ph
29
The categories of this paper are: funct-an
1
The categories of this paper are: cs
28
The categories of this paper are: alg-geom
7
The categories of this paper are: hep-th