Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Measurement of two-qubit states by quantum point contacts   We solve the master equations of two charged qubits measured by two serially
coupled quantum point contacts (QPCs). We describe two-qubit dynamics by
comparing entangled states with product states, and show that the QPC current
can be used for reading out results of quantum calculations and providing
evidences of two-qubit entanglement. We also calculate the concurrence of the
two qubits as a function of dephasing rate that originates from the
measurement. We conclude that coupled charge qubits can be effectively detected
by a QPC-based detector.

17
The categories of this paper are: q-fin
22
The categories of this paper are: chao-dyn
35
The categories of this paper are: mtrl-th
18
The categories of this paper are: econ
12
The categories of this paper are: nucl-th
21
The categories of this paper are: adap-org
7
The categories of this paper are: hep-th
26
The categories of this paper are: bayes-an
25
The categories of this paper are: patt-sol
6
The categories of this paper are: astro-ph
36
The categories of this paper are: cmp-lg
29
The categories of this paper are: funct-an
37
The categories of this paper are: supr-con
2
The categories of this paper are: math
20
The categories of this paper are: acc-phys
10
The categories of this paper are: q-bio