Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: On-demand quantum storage of photonic qubits in an on-chip waveguide   Photonic quantum memory is the core element in quantum information processing
(QIP). For the scalable and convenient practical applications, great efforts
have been devoted to the integrated quantum memory based on various waveguides
fabricated in solids. However, on-demand storage of qubits, which is an
essential requirement for QIP, is still challenging to be implemented using
such integrated quantum memory. Here we report the on-demand storage of
time-bin qubits in an on-chip waveguide memory on the surface of a
$^{151}$Eu$^{3+}$:Y$_2$SiO$_5$ crystal, utilizing the Stark modulated atomic
frequency comb protocol. A qubit storage fidelity of $99.3\%\pm0.2\%$ is
obtained with a input of 0.5 photons per pulse, far beyond the highest fidelity
achievable using the classical measure-and-prepare strategy. The developed
integrated quantum memory with the on-demand retrieval capability, represents
an important step towards practical applications of integrated quantum nodes in
quantum networks.

33
The categories of this paper are: plasm-ph
35
The categories of this paper are: mtrl-th
16
The categories of this paper are: stat
3
The categories of this paper are: physics
24
The categories of this paper are: dg-ga
32
The categories of this paper are: atom-ph
4
The categories of this paper are: cond-mat
12
The categories of this paper are: nucl-th
36
The categories of this paper are: cmp-lg
1
The categories of this paper are: cs
19
The categories of this paper are: eess
21
The categories of this paper are: adap-org
27
The categories of this paper are: comp-gas
26
The categories of this paper are: bayes-an
17
The categories of this paper are: q-fin
9
The categories of this paper are: nlin