Emily Mount

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.

Individual addressing of trapped 171Yb+ ion qubits using a microelectromechanical systems-based beam steering system

The ability to individually manipulate the increasing number of qubits is one of the many challenges towards scalable quantum information processing with trapped ions. Using micro-mirrors fabricated with micro-electromechanical systems technology, we focus laser beams on individual ions in a linear chain and steer the focal point in two dimensions. We demonstrate sequential single qubit gates on multiple 171Yb+ qubits and characterize the gate performance using quantum state tomography. Our system features negligible crosstalk to neighboring ions ( <3×10−4), and switching speed comparable to typical single qubit gate times (<2 μs).

Error compensation of single-qubit gates in a surface-electrode ion trap using composite pulses

The fidelity of laser-driven quantum logic operations on trapped ion qubits tend to be lower than microwave-driven logic operations due to the difficulty of stabilizing the driving fields at the ion location. Through stabilization of the driving optical fields and use of composite pulse sequences, we demonstrate high fidelity single-qubit gates for the hyperfine qubit of a

Scalable digital hardware for a trapped ion quantum computer

^{171}\text{Yb}^+

Application of OMEMS technology in trapped ion quantum computing

ion trapped in a microfabricated surface electrode ion trap. Gate error is characterized using a randomized benchmarking protocol, and an average error per randomized Clifford group gate of

Integrated Optical Systems Approach to Ion Trap Quantum Repeaters

3.6(3)\times10^{-4}

Scalable Quantum Information Processing with Trapped Ions

is measured. We also report experimental realization of palindromic pulse sequences that scale efficiently in sequence length.

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

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.

UV laser beam switching system for Yb trapped ion quantum information processing

Scalability is one of the main challenges of trapped ion based quantum computation, partly limited by the ability to manipulate the increasing number of quantum bits (qubits). For individual addressing of qubits, microelectromechanical systems (MEMS) technology allows one to design movable micromirrors to focus laser beams on individual ions and steer the focal point in two dimensions. This system is able to scale to multiple beams, has switching speeds comparable to typical single qubit gate times, and has negligible crosstalk on neighboring ions.

Single qubit manipulation in a microfabricated surface electrode ion trap.

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.