Jonathan David Sterk

Scaling and suppression of anomalous heating in ion traps

We measure and characterize anomalous motional heating of an atomic ion confined in the lowest quantum levels of a novel rf ion trap that features moveable electrodes. The scaling of heating with electrode proximity is measured, and when the electrodes are cooled from 300 to 150 K, the heating rate is suppressed by an order of magnitude. This provides direct evidence that anomalous motional heating of trapped ions stems from microscopic noisy potentials on the electrodes that are thermally driven. These observations are relevant to decoherence in quantum information processing schemes based on trapped ions and perhaps other charge-based quantum systems.

Efficient photoionization loading of trapped ions with ultrafast pulses

Atomic cadmium ions are loaded into radiofrequency ion traps by photoionization of atoms in a cadmium vapor with ultrafast laser pulses. The photoionization is driven through an intermediate atomic resonance with a frequency-quadrupled mode-locked Ti:sapphire laser that produces pulses of either 100-fs or 1-ps duration at a central wavelength of 229 nm. The large bandwidth of the pulses photoionizes all velocity classes of the Cd vapor, resulting in a high loading efficiency compared to previous ion trap loading techniques. Measured loading rates are compared with a simple theoretical model, and we conclude that this technique can potentially ionize every atom traversing the laser beam within the trapping volume. This may allow the operation of ion traps with lower levels of background pressures and less trap electrode surface contamination. The technique and laser system reported here should be applicable to loading most laser-cooled ion species.

Assembling a ring-shaped crystal in a microfabricated surface ion trap

We report on experiments with a microfabricated surface trap designed for trapping a chain of ions in a ring. Uniform ion separation over most of the ring is achieved with a rotationally symmetric design and by measuring and suppressing undesired electric fields. After minimizing these fields the ions are confined primarily by an rf trapping pseudo-potential and their mutual Coulomb repulsion. The ring-shaped crystal consists of approximately 400 Ca

Ion-photon quantum interface : entanglement engineering.

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Demonstration of a scalable, multiplexed ion trap for quantum information processing

ions with an estimated average separation of 9

Robust self-consistent closed-form tomography of quantum logic gates on a trapped ion qubit.

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The Trap Technique

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Surface ion trap structures with excellent optical access for quantum information processing

Distributed quantum information processing requires a reliable quantum memory and a faithful carrier of quantum information. Trapped ion qubits are the leading realization for quantum information storage, and photonic qubits are the natural choice for the transport of quantum information. The capability to entangle photons with trapped ions in a highly efficient (scalable) fashion is an important achievement. Here, we leverage the active and successful development of micro-fabricated semiconductor ion traps at the Sandia National Laboratory MESA facility, and integrate micro optical components. Compared to current efforts in academic settings combining macro-sized ion traps and optics, a micro device will result in the dramatically increased speed and fidelity of ion-trap based quantum networking protocols. Integrating smaller components will directly allow for a stronger quantum coherent interface between a single trapped ion and a single photon. If successful, this technology could lead to new demonstrations of fundamental physics properties and would open new avenues for scalable quantum networking architectures.