Controlling fast transport of cold trapped ions
*
A. Walther , F. Ziesel, T. Ruster, S. T. Dawkins, K. Ott, M. Hettrich, K. Singer, F. Schmidt-Kaler and U.
Poschinger
QUANTUM, Institut für Physik, Universität Mainz, Staudingerweg 7, 55128 Mainz, Germany
*
email: andreas.walther@fysik.lth.se; current address: Department of Physics, Lund University, Box
118, 221 00 Lund, Sweden
Quantum information processing has the potential for a large impact on future technology,
exemplified by quantum computers that could solve certain difficult problems in exponentially fewer
steps compared to any known classical algorithm. The experimental search for a suitable
implementation is currently being conducted on a wide front, but the best results to date have been
obtained in systems of trapped single ions [1]. Currently about 10 qubits is possible in a single trap,
and one of the main ideas for moving significantly beyond this number is architectures that contain
multiple traps, together with physical transport of ions between sections [2]. In such a scheme the
transport operations necessarily needs to be very fast, on
the same timescale as the gates, but so far this has not
been achieved without significant heating of the ions.
Here, we present an experimental realization of
very fast
transport of ions between two segments
in a microtrap
[3], as shown in Fig. 1. The ions are
shuttled a distance of
more than 104 times its
wavefunction size during a time
that corresponds
to only 5 motional cycles of the trap
Fig 1. By fast sequences of voltages an ion is
(280 μm in
3.6 μs). Such fast transport is significantly
transported from one segment in a microtrap to
non-
adibatic, creating more than 100 phonons of
the next, in 3.6 μs, corresponding to only 5
motional energy; however, we show that with
very
internal motional cycles.
precise control of the transport ramps, the
internal
oscillations of the ions can be stopped simultaneously as
the shuttling, making the ions end up with only an additional 0.1 phonons of energy, in a state still
close to the motional ground state. In addition, we demonstrate that spin-motion entangled states
survive the transport.
[1] R. Blatt and D. Wineland, “Entangled states of trapped atomic ions”, Nature (London) 453, 1008
(2008)
[2] D. Kielpinski, C. Monroe and D. Wineland, “Architecture for a large-scale ion-trap quantum
computer”, Nature (London) 417, 709 (2002)
[3] A. Walther, F. Ziesel, T. Ruster, S. T. Dawkins, K. Ott, M. Hettrich, K. Singer, F. Schmidt-Kaler and U.
Poschinger, “Controlling Fast Transport of Cold Trapped Ions”, Phys. Rev. Lett. 109, 080501 (2012)