QUANTUM SCIENCE & ENGINEERING AT HRL

HRL Laboratories is a world leader in developing solid-state technology for quantum computing and networking. We are advancing a variety of technologies including silicon quantum-dot qubits, silicon carbide photonics, superconducting nanowire single photon detectors, chip-scale atom-optics components, and microwave-dot hybrid systems. These efforts build on our decades of experience in research and development and draw on robust collaborations with academia.

HRL’s campus in Malibu, CA is equipped with on-site epitaxial semiconductor growth tools, a state-of-the-art 10,000-square-foot nano-fabrication cleanroom facility, high-performance computational resources for theory and simulation, and cryogenic test and measurement laboratories. It is the same site that originated world-changing inventions such as the self-aligned gate MOSFET and the world’s first laser.

What differentiates HRL’s approach from other professional quantum efforts?

• Long-term strategy – The potential of quantum technology extends far beyond immediate applications, but will take time to realize.
• Collaborative – We organize around the fact that quantum engineering requires a highly diverse set of skills and backgrounds.
• Vertically integrated – We leverage the rapid development cycles made possible by on-site epitaxial semiconductor growth, device fabrication, software development, qubit testing, and theoretical analysis.
• Pioneering – Many of our technological approaches are not yet mainstream, but have demonstrated and compelling advantages.
• Experience – HRL has a long history as a leader in key enabling technologies such as materials growth and characterization, high-performance circuits, advanced packaging, and quantum information science.

Scientists, engineers, software developers, graduate students, and undergraduate students who are interested in quantum science and engineering are encouraged to apply to our open positions.

Careers in Quantum Science at HRL

Selected HRL Publications

We demonstrate universal logic operations with two EO qubits in silicon, including single-qubit gates, CNOT, CZ, and SWAP. We also demonstrate LCCZ, which is expected to reduce leakage spreading in future quantum processors.

"Universal logic with encoded spin qubits in silicon," A. J. Weinstein, Nature 615, 817 (2023). (arXiv) (Informational YouTube Video)

We demonstrate rapid, high-fidelity state preparation and measurement in exchange-only Si/SiGe triple-quantum-dot qubits.

"Fast and high-fidelity state preparation and measurement in triple-quantum-dot spin qubits," J. Z. Blumoff et al., Quantum 3, 010352 (2022). (arXiv)

We present an exchange-only Si qubit device platform that combines the throughput of CMOS-like wafer processing with the versatility of direct-write lithography.

"A flexible design platform for Si/SiGe exchange-only qubits with low disorder," Wonill Ha et al., Nano Lett.2022, 22, 3, 1443 (2021). (arXiv)

We design and train a convolutional neural network to quantify qualitative features affecting device functionality.

"Optimization of quantum-dot qubit fabrication via machine learning," Antonio B. Mei et al., Appl. Phys. Lett., 118, 204001 (2021). (arXiv)

DAPS allows us to systematically probe multiple valley and orbital states of individual dots in Si/SiGe QWs with varied widths and growth conditions.

"Detuning Axis Pulsed Spectroscopy of Valley-Orbital States in Si/SiGe Quantum Dots," E. Chen et al., Phys. Rev. Applied, 15, 044033 (2021). (arXiv)

Low-field T₂ in exchange-only qubits in the absence of magnetic field gradients results from electrical quadrupole effects from the ⁷³Ge nuclei.

"Magnetic Gradient Fluctuations from Quadrupolar ⁷³Ge in Si/SiGe Exchange-Only Qubits," J. Kerckhoff et al., PRX Quantum, 2, 010347 (2021). (arXiv)

Optimizing the coupling between a triple-quantum-dot qubit and a microwave resonator.

"Resonant exchange operation in triple-quantum-dot qubits for spin-photon transduction," A. Pan et al., Quantum Sci. and Tech. 5, 034005 (2020). (arXiv)

We describe an excited-state spectroscopy technique which directly measures singlet-triplet energy splitting and demonstrate this technique on a Si/SiGe double-dot, finding the singlet-triplet splitting to be highly tunable.

"Spin-Blockade Spectroscopy of Si/SiGe Quantum Dots," A. M. Jones et al., Phys. Rev. Applied 12, 014026 (2019). (arXiv)

Demonstrating randomized benchmarking of a triple-quantum-dot qubit in Si with proper treatment of leakage out of the encoded subspace.

"Quantifying error and leakage in an encoded Si/SiGe triple-dot qubit," R. W. Andrews et al., Nature Nanotechnology, 14, 747 (2019). (arXiv)

A proposal for making a fault-tolerant logical qubit out of a linear chain of quantum dots using a minimum of hardware and control resources.

"Logical Qubit in a Linear Array of Semiconductor Quantum Dots," C. Jones et al., Physical Review X, 8, 021058 (2018). (arXiv)

A proposal for entangling electrically controlled arrays of quantum dot qubits with flying photonic qubits.

"Optically Loaded Semiconductor Quantum Memory Register," D. Kim et al., Physical Review Applied, 5, 024014 (2016). (arXiv)

Demonstration of 'symmetric' mode operation to reduce susceptibility of exchange-based control to charge noise.

"Reduced Sensitivity to Charge Noise in Semiconductor Spin Qubits via Symmetric Operation," M. D. Reed et al., Physical Review Letters, 116, 110402 (2016). (arXiv)

Developing appropriate heterostructure stacks for highly performing silicon qubits.

"Metamorphic materials for quantum computing.," P. Deelman et al., MRS Bulletin, 41(3), 224 (2016).

Optimizing information transfer in faulty quantum networks.

"Design and analysis of communication protocols for quantum repeater networks," C. Jones et al., New Journal of Physics, 18, 083015 (2016). (arXiv)

Demonstration of two-axis coherent control of the first triple quantum dot in isotopically enhanced Si.

"Isotopically enhanced triple-quantum-dot qubit," K. Eng et al., Science Advances, 1, e1500214 (2015).

Demonstration of an improved gate and doping architecture for silicon qubits.

"Undoped accumulation-mode Si/SiGe quantum dots," M. G. Borselli et al., Nanotechnology 26, 375202 (2015). (arXiv)

First demonstration of coherent single-spin control in a Si/SiGe heterostructure.

"Coherent singlet-triplet oscillations in a silicon-based double quantum dot," B. M. Maune et al. Nature, 481, 344 (2012).

Full-permutation dynamical decoupling in triple-quantum-dot spin qubits.

"Full-permutation dynamical decoupling in triple-quantum-dot spin qubits," B. Sun et al., (2022). (arXiv)

Selected Collaborative Publications

We demonstrate a readout visibility greater than 99% and average single-qubit gate fidelities above 99.95% in a single-spin Loss-DiVincenzo (LD) qubit

"High-Fidelity State Preparation, Quantum Control, and Readout of an Isotopically Enriched Silicon Spin Qubit," A.R. Mills et al., Phys. Rev. Applied 18, 064028 (2022). (arXiv)

Demonstrated method for efficient loading of atoms into portable cold-atom microsystems.

"Active stabilization of alkali-atom vapor density with a solid-state electrochemical alkali-atom source," S. Kang, R. Mott, et al., Opt. Express, 26, 3696-3701 (2018).

Electron spins in silicon quantum dots are excellent qubits because they have long coherence times and high gate fidelities and are compatible with advanced semiconductor manufacturing techniques.

"Coherent spin-valley oscillations in silicon," X. Cai et al., Nat. Phys. (2023),

2023 APS March Meeting Presentations

2022 APS March Meeting Presentations

2020 APS March Meeting Presentations

Contact

Email: quantum[at]hrl.com