Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Probing the superconducting condensate on a nanometer scale   Superconductivity is a rare example of a quantum system in which the
wavefunction has a macroscopic quantum effect, due to the unique condensate of
electron pairs. The amplitude of the wavefunction is directly related to the
pair density, but both amplitude and phase enter the Josephson current : the
coherent tunneling of pairs between superconductors. Very sensitive devices
exploit the superconducting state, however properties of the {\it condensate}
on the {\it local scale} are largely unknown, for instance, in unconventional
high-T$_c$ cuprate, multiple gap, and gapless superconductors.
  The technique of choice would be Josephson STS, based on Scanning Tunneling
Spectroscopy (STS), where the condensate is {\it directly} probed by measuring
the local Josephson current (JC) between a superconducting tip and sample.
However, Josephson STS is an experimental challenge since it requires stable
superconducting tips, and tunneling conditions close to atomic contact. We
demonstrate how these difficulties can be overcome and present the first
spatial mapping of the JC on the nanometer scale. The case of an MgB$_2$ film,
subject to a normal magnetic field, is considered.

34
The categories of this paper are: chem-ph
35
The categories of this paper are: mtrl-th
12
The categories of this paper are: nucl-th
10
The categories of this paper are: q-bio
28
The categories of this paper are: alg-geom
9
The categories of this paper are: nlin
23
The categories of this paper are: solv-int
2
The categories of this paper are: math
27
The categories of this paper are: comp-gas
21
The categories of this paper are: adap-org
16
The categories of this paper are: stat
29
The categories of this paper are: funct-an
19
The categories of this paper are: eess
7
The categories of this paper are: hep-th
33
The categories of this paper are: plasm-ph
36
The categories of this paper are: cmp-lg