13 research outputs found
Optimal Phonon-to-Spin Mapping in a system of a trapped ion
We propose a protocol for measurement of the phonon number distribution of a
harmonic oscillator based on selective mapping to a discrete spin-1/2 degree of
freedom. We consider a system of a harmonically trapped ion, where a transition
between two long lived states can be driven with resolved motional sidebands.
The required unitary transforms are generated by amplitude-modulated
polychromatic radiation fields, where the time-domain ramps are obtained from
numerical optimization by application of the Chopped RAndom Basis (CRAB)
algorithm. We provide a detailed analysis of the scaling behavior of the
attainable fidelities and required times for the mapping transform with respect
to the size of the Hilbert space. As one application we show how the mapping
can be employed as a building block for experiments which require measurement
of the work distribution of a quantum process
Sideband cooling and coherent dynamics in a microchip multi-segmented ion trap
Miniaturized ion trap arrays with many trap segments present a promising
architecture for scalable quantum information processing. The miniaturization
of segmented linear Paul traps allows partitioning the microtrap in different
storage and processing zones. The individual position control of many ions -
each of them carrying qubit information in its long-lived electronic levels -
by the external trap control voltages is important for the implementation of
next generation large-scale quantum algorithms.
We present a novel scalable microchip multi-segmented ion trap with two
different adjacent zones, one for the storage and another dedicated for the
processing of quantum information using single ions and linear ion crystals: A
pair of radio-frequency driven electrodes and 62 independently controlled DC
electrodes allows shuttling of single ions or linear ion crystals with
numerically designed axial potentials at axial and radial trap frequencies of a
few MHz. We characterize and optimize the microtrap using sideband spectroscopy
on the narrow S1/2 D5/2 qubit transition of the 40Ca+ ion, demonstrate
coherent single qubit Rabi rotations and optical cooling methods. We determine
the heating rate using sideband cooling measurements to the vibrational ground
state which is necessary for subsequent two-qubit quantum logic operations. The
applicability for scalable quantum information processing is proven.Comment: 17 pages, 11 figure