Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: State reconstruction for composite systems of two spatial qubits   Pure entangled states of two spatial qudits have been produced by using the
momentum transverse correlation of the parametric down-converted photons [Phys.
Rev. Lett. \textbf{94} 100501]. Here we show a generalization of this process
to enable the creation of mixed states of spatial qudits and by using the
technique proposed we generate mixed states of spatial qubits. We also report
how the process of quantum tomography is experimentally implemented to
characterize these states. This tomographic reconstruction is based on the free
evolution of spatial qubits, coincidence detection and a filtering process. The
reconstruction method can be generalized for the case of two spatial qudits.

23
The categories of this paper are: solv-int
10
The categories of this paper are: q-bio
6
The categories of this paper are: astro-ph
26
The categories of this paper are: bayes-an
11
The categories of this paper are: hep-lat
16
The categories of this paper are: stat
29
The categories of this paper are: funct-an
0
The categories of this paper are: hep-ph
31
The categories of this paper are: ao-sci
17
The categories of this paper are: q-fin
14
The categories of this paper are: math-ph
37
The categories of this paper are: supr-con
30
The categories of this paper are: q-alg
8
The categories of this paper are: hep-ex
20
The categories of this paper are: acc-phys
21
The categories of this paper are: adap-org