Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Imaging a Coupled Quantum Dot - Quantum Point Contact System   We performed measurements on a quantum dot and a capacitively coupled quantum
point contact by using the sharp metallic tip of a low-temperature scanning
force microscope as a scanned gate. The quantum point contact served as a
detector for charges on the dot or nearby. It allowed us to distinguish single
electron charging events in several charge traps from charging events on the
dot. We analyzed the tip-induced potential quantitatively and found its shape
to be independent of the voltage applied to the tip within a certain range of
parameters. We estimate that the trap density is below 0.1% of the doping
density and that the interaction energy between the quantum dot and a trap is a
significant portion of the dot's charging energy. Possibly, such charge traps
are the reason for frequently observed parametric charge rearrangements.

18
The categories of this paper are: econ
8
The categories of this paper are: hep-ex
2
The categories of this paper are: math
37
The categories of this paper are: supr-con
7
The categories of this paper are: hep-th
1
The categories of this paper are: cs
26
The categories of this paper are: bayes-an
34
The categories of this paper are: chem-ph
36
The categories of this paper are: cmp-lg
15
The categories of this paper are: nucl-ex
9
The categories of this paper are: nlin
22
The categories of this paper are: chao-dyn
6
The categories of this paper are: astro-ph
33
The categories of this paper are: plasm-ph
19
The categories of this paper are: eess
24
The categories of this paper are: dg-ga