Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Possible realization of an ideal quantum computer in Josephson junction
  array   We introduce a new class of Josephson arrays which have non-trivial topology
and exhibit a novel state at low temperatures. This state is characterized by
long range order in a two Cooper pair condensate and by a discrete topological
order parameter. These arrays have degenerate ground states with this
degeneracy 'protected' from the external perturbations (and noise) by the
topological order parameter. We show that in ideal conditions the low order
effect of the external perturbations on this degeneracy is exactly zero and
that deviations from ideality lead to only exponentially small effects of
perturbations. We argue that this system provides a physical implementation of
an ideal quantum computer with a built in error correction and show that even a
small array exhibits interesting physical properties such as superconductivity
with double charge, 4e, and extremely long decoherence times.

21
The categories of this paper are: adap-org
31
The categories of this paper are: ao-sci
33
The categories of this paper are: plasm-ph
22
The categories of this paper are: chao-dyn
30
The categories of this paper are: q-alg
19
The categories of this paper are: eess
10
The categories of this paper are: q-bio
29
The categories of this paper are: funct-an
3
The categories of this paper are: physics
18
The categories of this paper are: econ
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The categories of this paper are: dg-ga
23
The categories of this paper are: solv-int
14
The categories of this paper are: math-ph
20
The categories of this paper are: acc-phys
17
The categories of this paper are: q-fin
34
The categories of this paper are: chem-ph