Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Two-step hyperentanglement purification with the quantum-state-joining
  method   Hyperentanglement is a promising resource in quantum information processing,
especially for increasing the channel capacity of long-distance quantum
communication. Hyperentanglement purification is an important method to obtain
high-fidelity nonlocal hyperentangled states from mixed hyperentangled states
in a long-distance quantum communication process with noisy channels. Here, we
present a two-step hyperentanglement purification protocol for nonlocal mixed
hyperentangled states with polarization bit-flip errors and spatial-mode
phase-flip errors, resorting to polarization-spatial phase-check quantum
nondemolition detectors and the quantum-state-joining method (QSJM). With QSJM,
the protocol can preserve the states that are discarded in the previous
hyperentanglement purification protocols. It has the advantage of a high
efficiency, and it is useful for improving the entanglement of photon systems
with several degrees of freedom in long-distance high-capacity quantum
communication.

14
The categories of this paper are: math-ph
4
The categories of this paper are: cond-mat
19
The categories of this paper are: eess
22
The categories of this paper are: chao-dyn
24
The categories of this paper are: dg-ga
30
The categories of this paper are: q-alg
36
The categories of this paper are: cmp-lg
15
The categories of this paper are: nucl-ex
20
The categories of this paper are: acc-phys
34
The categories of this paper are: chem-ph
17
The categories of this paper are: q-fin
10
The categories of this paper are: q-bio
12
The categories of this paper are: nucl-th
11
The categories of this paper are: hep-lat
7
The categories of this paper are: hep-th
3
The categories of this paper are: physics