Daniel Gaultney

Scattering cross-section of a transformation optics-based metamaterial cloak

We present experimental quantitative scattering cross-section (SCS) measurements for a metamaterial cloak. The cloak is nearly identical to that reported in 2006; however, quantitative experimental measurements have not yet been reported for such a structure. This cylindrically symmetric cloak is designed to operate at a frequency of 10 GHz and to reduce the SCS of a cylinder 50 mm in diameter. Despite being only a crude approximation of the ideal transformation optical design, the fabricated metamaterial cloak is shown to reduce the SCS of the cylinder over the frequency range from 9.91  to 10.14 GHz, a span of 230 MHz or a 2.3% bandwidth. The maximum reduction in the SCS is 24%. This result provides a useful experimental, quantitative benchmark that can form the basis for comparison of the performances of future improved cloaking structures.

High speed, high fidelity detection of an atomic hyperfine qubit

Fast and efficient detection of the qubit state in trapped ion systems is critical for implementing quantum error correction and performing fundamental tests such as a loophole-free Bell test. In this work we present a simple qubit state detection protocol for a (171)Yb+ hyperfine atomic qubit trapped in a microfabricated surface trap, enabled by high collection efficiency of the scattered photons and low background photon count rate. We demonstrate average detection times of 10.5, 28.1, and 99.8 μs, corresponding to state detection fidelities of 99%, 99.856(8)%, and 99.915(7)%, respectively.

Scalable digital hardware for a trapped ion quantum computer

Many of the challenges of scaling quantum computer hardware lie at the interface between the qubits and the classical control signals used to manipulate them. Modular ion trap quantum computer architectures address scalability by constructing individual quantum processors interconnected via a network of quantum communication channels. Successful operation of such quantum hardware requires a fully programmable classical control system capable of frequency stabilizing the continuous wave lasers necessary for loading, cooling, initialization, and detection of the ion qubits, stabilizing the optical frequency combs used to drive logic gate operations on the ion qubits, providing a large number of analog voltage sources to drive the trap electrodes, and a scheme for maintaining phase coherence among all the controllers that manipulate the qubits. In this work, we describe scalable solutions to these hardware development challenges.

Integrated Optical Systems Approach to Ion Trap Quantum Repeaters

A quantum communication node with high quality quantum memories and photonic interfaces capable of quantum logic operations provide a technology platform for realizing quantum repeaters. We will discuss a viable implementation in trapped ion systems.

Scalable Quantum Information Processing with Trapped Ions

We present a scalable approach to quantum information processing utilizing trapped ions and photons. Ions trapped in microfabricated surface traps provide a practical platform for realizing quantum networks of distributed computing nodes and quantum repeaters.

Long-lived ion qubits in a microfabricated trap for scalable quantum computation

We report state detection, single qubit coherent operations and Raman sideband cooling to near the motional ground state by trapping a single 171Yb+ ion in a surface trap designed and fabricated at Sandia National Laboratories.