Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Large-scale superconductivity-induced conductance suppression in
  mesoscopic normal-superconducting structures   Experiments on hybrid superconducting normal-metal structures have revealed
that even in the absence of tunnel junctions the onset of superconductivity can
lead to a decrease in the electrical conductance by an amount many orders of
magnitude greater than $e^2/h$. In this Letter we provide a theory of this
phenomenon which shows that it originates from an instability in 4 - probe
conductance measurements which is absent from 2-probe measurements. We compare
the zero-bias,zero-temperature 4-probe conductances $G_{N}$ and $G_{S}$ of a
normal diffusive metal in contact with a superconductor in both the normal (N)
and superconducting (S) states respectively. In the absence of tunnel barriers,
the ensemble average of the difference $\delta G=G_{S}-G_N$ vanishes, in
agreement with quasi-classical theory. However we also predict that there
exists macroscopic sample specific fluctuations in $\delta G$, which lie beyond
quasi-classical theory and allow large negative values of $\delta G$ to occur.

24
The categories of this paper are: dg-ga
25
The categories of this paper are: patt-sol
16
The categories of this paper are: stat
14
The categories of this paper are: math-ph
1
The categories of this paper are: cs
6
The categories of this paper are: astro-ph
27
The categories of this paper are: comp-gas
22
The categories of this paper are: chao-dyn
0
The categories of this paper are: hep-ph
10
The categories of this paper are: q-bio
30
The categories of this paper are: q-alg
36
The categories of this paper are: cmp-lg
23
The categories of this paper are: solv-int
15
The categories of this paper are: nucl-ex
7
The categories of this paper are: hep-th
20
The categories of this paper are: acc-phys