APS March Meeting 2014
Volume 59, Number 1
Monday–Friday, March 3–7, 2014;
Denver, Colorado
Session S34: Focus Session: AMO Quantum Information Processing: Photons and Atoms
8:00 AM–11:00 AM,
Thursday, March 6, 2014
Room: 704
Sponsoring
Units:
GQI DAMOP
Chair: Grant Biedermann, Sandia National Laboratories
Abstract ID: BAPS.2014.MAR.S34.8
Abstract: S34.00008 : Robust and Addressable Control of Atomic Qubits and Qudits
9:48 AM–10:24 AM
Preview Abstract
Abstract
Author:
Poul Jessen
(College of Optical Sciences and Center for Quantum Information and Control (CQuIC), University of Arizona)
The standard paradigm for quantum computation and simulation with neutral
atoms assumes that constituent atoms can be used as individually addressable
qubits. To accomplish this in optical lattices with sub-micron atom
separation, we have developed a resonance addressing scheme that combines a
position dependent light shift of the qubit transition with resonant
microwave ($\mu $w) pulses. In a proof-of-principle experiment, we show that
numerically optimized composite pulses can implement quantum gates on Cs
qubits at targeted lattice sites, with minimal cross-talk to neighboring
sites and significant robustness against uncertainty in the atom position.
Coherence is verified through two-pulse experiments, and the average gate
fidelity is measured to be 95$+$/-3{\%} [1]. Because most atoms have more
than two accessible levels, one might also consider if the existing toolbox
for qubit control can be extended to $d$-level systems (qudits). Over the past
several years we have used the 16-dimensional ground hyperfine manifold of
cold, untrapped Cs atoms as an experimental testbed for such work. Driving
the atoms with a combination of phase modulated radio frequency (rf) and
$\mu $w magnetic fields, we use numerical optimization techniques to design
control waveforms (rf and $\mu $w phases as function of time) that
accomplish a wide range of control tasks, from quantum state-to-state maps
[2] to full unitary transformations, with average fidelities that vary from
\textgreater 99{\%} for the former to $\sim$ 98{\%} for the latter.
We further show that tools for inhomogeneous control and dynamical
decoupling can be generalized to qudits, allowing transformations that are
robust to static as well as dynamic perturbations, and thus in principle
compatible with optical traps and the resonance addressing scheme
demonstrated for qubits.
\\[4pt]
[1] J. H. Lee et al., Nature Comm. \textbf{4}, Article no. 2027 (2013),
doi:10.1038/ncomms3027.\\[0pt]
[2] A. Smith et al, Phys. Rev. Lett. \textbf{111}, 170502 (2013).
To cite this abstract, use the following reference: http://meetings.aps.org/link/BAPS.2014.MAR.S34.8