Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Turnstile behaviour of the Cooper-pair pump   We have experimentally studied the behaviour of the so-called Cooper pair
pump (CPP) with three Josephson junctions, in the limit of small Josephson
coupling EJ < EC. These experiments show that the CPP can be operated as a
traditional turnstile device yielding a gate-induced current 2ef in the
direction of the bias voltage, by applying an RF-signal with frequency f to the
two gates in phase, while residing at the degeneracy node of the gate plane.
Accuracy of the CPP during this kind of operation was about 3% and the
fundamental Landau-Zener limit was observed to lie above 20 MHz. We have also
measured the current pumped through the array by rotating around the degeneracy
node in the gate plane. We show that this reproduces the turnstile-kind of
behavior. To overcome the contradiction between the obtained e-periodic
DC-modulation and a pure 2e-behaviour in the RF-measurements, we base our
observations on a general principle that the system always minimises its
energy. It suggests that if the excess quasiparticles in the system have a
freedom to tunnel, they will organize themselves to the configuration yielding
the highest current.

22
The categories of this paper are: chao-dyn
26
The categories of this paper are: bayes-an
28
The categories of this paper are: alg-geom
0
The categories of this paper are: hep-ph
18
The categories of this paper are: econ
17
The categories of this paper are: q-fin
14
The categories of this paper are: math-ph
1
The categories of this paper are: cs
20
The categories of this paper are: acc-phys
16
The categories of this paper are: stat
30
The categories of this paper are: q-alg
2
The categories of this paper are: math
23
The categories of this paper are: solv-int
3
The categories of this paper are: physics
31
The categories of this paper are: ao-sci
15
The categories of this paper are: nucl-ex