Josephson Junction Arrays with Bose-Einstein Condensates
F. S. Cataliotti,123
S. Burger,12
C. Fort,12
P. Maddaloni,124
F. Minardi,12
A. Trombettoni,25
A. Smerzi,25
M. Inguscio123*
We report on the direct observation of an oscillating atomic
current in a one-dimensional array of Josephson junctions realized with
an atomic Bose-Einstein condensate. The array is created by a laser
standing wave, with the condensates trapped in the valleys of the
periodic potential and weakly coupled by the interwell barriers. The
coherence of multiple tunneling between adjacent wells is continuously
probed by atomic interference. The square of the small-amplitude
oscillation frequency is proportional to the microscopic tunneling rate
of each condensate through the barriers and provides a direct
measurement of the Josephson critical current as a function of the
intermediate barrier heights. Our superfluid array may allow
investigation of phenomena so far inaccessible to superconducting
Josephson junctions and lays a bridge between the condensate dynamics
and the physics of discrete nonlinear media.
1 European Laboratory for Non-Linear
Spectroscopy (LENS) and
2 Istituto Nationale per la
Fisica della Materia (INFM), L.go E. Fermi 2, I-50125 Firenze, Italy.
3 Dipartimento di Fisica, Università di
Firenze, L.go E. Fermi 2, I-50125 Firenze, Italy.
4 Dipartimento di Fisica, Università di
Padova, via F. Marzolo 8, I-35131 Padova, Italy.
5 International School for Advanced Studies (SISSA),
via Beirut 2/4, I-34014 Trieste, Italy.
*
To whom correspondence should be addressed. E-mail:
inguscio@lens.unificit
