#QuantumSystemsAccelerator

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Quantum Systems Accelerator Grows Trapped-Ion Qubit Arrays

Accelerator for Quantum Systems

The Quantum Systems Accelerator has been forging new ground to hasten the development of flexible, reliable quantum computers with capabilities far beyond those of classical processors. Quantum system foundations have been known for decades, but precision engineering is still needed to construct machines that employ them. The same properties that make quantum computing strong at this scale also make it hard to employ.

National Quantum Information Science Research Centre is Quantum Systems Accelerator. It pursues new physics frontiers with a science-first strategy to answer large science questions that standard methodologies cannot handle. QSA co-designs cutting-edge quantum devices in superconducting circuits, trapped ions, and neutral atoms. A team of dozens of quantum engineering and manufacturing professionals led by Lawrence Berkeley National Laboratory (Berkeley Lab) and Sandia National Laboratories is called QSA. Its ultimate goal is to provide a quantum advantage in science.

The QSA fosters collaboration by sharing experimental methods, cutting-edge scalable technology, and quantum information theory across diverse application areas. Besides business and academic partners, this collaborative ecosystem includes 15 institutions globally and is vital for its cutting-edge investigations and quantum physics advancements.

Recent QSA research has advanced several aspects of quantum technology and basic physics, as outlined in numerous important:

Trapped-Ion Quantum Computing Advances

Trapped-ion quantum computing scales, works faster, and uses new measurements. The well-established platform of trapped-ion systems uses electric fields to transport and trap ions and lasers to change their quantum states to create extended chains of interconnected qubits with long coherence periods.

The “Enchilada Trap”: Jonathan Sterk led a Sandia National Laboratories QSA team that designed, built, and tested the groundbreaking ion trap chip. This trap holds 200 ions. Elevating RF electrodes and deleting insulating dielectric material reduce radiofrequency (RF) power dissipation, which can limit trap size and complexity. The trap's junction-connected operational zones pave the groundwork for future traps with orders of magnitude more qubits.

Paper on Parallel Gate Operations: Under Yingyue Zhu's supervision, a University of Maryland QSA team addressed a bottleneck in trapped-ion systems' sequential physical gate operations. They showed parallel quantum gate  operations. In previous installations, interference occurred because every gate employed the same motional modes.

The Zhu group solved this by commanding qubits in space in several directions at once, allowing simultaneous operations without overhead or interference. This idea allows quantum computing to scale, improve information flow, increase speed and processing power, and reduce decoherence through faster operations.

Large-Scale Entanglement Research: Chris Monroe's team's Or Katz led a Duke University QSA group that studied entangling numerous ions simultaneously to scale quantum processors. They invented “squeezing” to entangle several qubits at once.

This technology allows researchers to entangle the spins of several ions simultaneously instead of pairwise entanglement. It affects the scale of ions' motion or position in a spin-dependent manner. This novel method efficiently generates quantum entangling processes that would be difficult to build using standard paired methods, opening up new quantum information applications.

Mid-Circuit Measurements Study: Daiwei Zhu and colleagues at the University of Maryland's QSA research group examined mid-circuit measurements' unique capabilities. Many quantum computing designs struggle with the issue of measuring one qubit affecting neighbouring qubits if it is not properly isolated.

The scientists employed precision voltage modulation to spatially separate ion chain segments to shuttle isolated ions for measurement without disturbing neighbouring segments. This method allowed them to create two interactive protocols, one based on a Computational Bell Test and the other on the Learning With Errors (LWE) problem, to prove quantum advantage classically. This was the first computational definition of quantumness and a model for cryptographic methods that interact with a classical verifier. Mid-circuit measurements can also improve quantum operations and troubleshoot quantum structures.

Quantum Devices and Methods for Physics

The “QSA Harnesses Quantum Devices and Techniques to Explore Physics – QSA��� describes how QSA co-designs state-of-the-art quantum devices across several technologies to explore new physics frontiers.

An experimental team led by Principal Investigator Jun Ye and JILA (a joint institute at the University of Colorado Boulder and NIST) confirmed general relativity's validity by improving exact measurements. Over 100,000 ultracold strontium atoms in an optical lattice were utilised to study time dilation on a millimeter-scale atomic ensemble with unprecedented precision. This work detected minute gravity-induced time changes 50 times more accurately than previous clocks, setting a new standard for precision and quantum coherence. The team improved clock quantum state management by adjusting optical trap depth to optimise coherence times and measurement stability.

A JILA QSA team led by Professor James K. Thompson devised a strategy to improve a quantum sensor's accuracy by exceeding the standard quantum limit (SQL). In a typical matter-wave interferometer, atomic unpredictability limits SQL precision.

This research used quantum entanglement to link the quantum states of 700 ultracold rubidium atoms to improve interferometer results by 1.7 dB. They targeted rubidium atoms in a high-finesse optical cavity to improve light-atom interaction and enable complex quantum phenomena. Light was utilised to quantify and cancel quantum noise and as a shared quantum network for atoms to interact and be “quieter” by the team. This invention enables precise physics measurements.

The non-invasive screening method developed by Sandia National Laboratories' Andrew (Andy) Mounce, Pauli Kehayias, and Luca Bass uses a nitrogen-vacancy (NV)-based quantum sensor to monitor microwave frequency magnetic fields.

This method confirms quantum device behaviour compared to simulations and allows early, sensitive fault screening without device damage. This research builds on the same group's past work on localised electrical shorts in ion traps and measuring higher-frequency magnetic fields for superconducting and trapped-ion quantum computing platforms.

Lawrence Berkeley National Laboratory created the magnetoARPES technology, an adaption of Angle-Resolved Photoemission Spectroscopy (ARPES). When ARPES observed with a magnetic field, electron paths changed. Innovative magnetoARPES tackles this issue by restricting the magnetic field to a tiny layer 100 micrometres from the sample surface.

Berkeley Lab's top synchrotron light source produced powerful, concentrated X-ray beams on thin graphene samples that allowed photoelectrons to pass through the confined magnetic field with only slight deflection, enabling high-resolution electron energy and emission angle measurements. This technology improves quantum technology manufacturing by understanding how magnetic fields and quantum processes affect material electronic structure.

The QSA team is solving previously unsolvable issues quicker by pushing fundamental physics and improving quantum computers' efficiency, scalability, dependability, and interaction.