A quantum computing testbed available to the research community
QSCOUT is a quantum computing testbed based on trapped ions that is available to the research community as an open platform for a range of quantum computing applications.
C. Campbell, F. T. Chong, D. Dahl, P. Frederick, P. Goiporia, P. Gokhale, B. Hall, S. Issa, E. Jones, S. Lee, A. Litteken, V. Omole, D. Owusu-Antwi, M. A. Perlin, R. Rines, K. N. Smith, N. Goss, A. Hashim, R. Naik, E. Younis, D. Lobser, C. G. Yale, B. Huang, J. Liu. “Superstaq: Deep Optimization of Quantum Programs,”2023 IEEE International Conference on Quantum Computing and Engineering (QCE), pp. 1020-1032 (2023)
P. Richerme, M. C. Revelle, C. G. Yale, D. Lobser, A. D. Burch, S. M. Clark, D. Saha, M. A. Lopez-Ruiz, A. Dwivedi, J. M. Smith, S. A. Norrell, A. Sabry, S. S. Iyengar. “Quantum Computation of Hydrogen Bond Dynamics and Vibrational Spectra.” The Journal of Physical Chemistry Letters14, 7256-7263 (2023)
View a complete listing of up to date QSCOUT publications. (denoted by QSCOUT icon)
“The goal of QSCOUT is to build, maintain, and provide access to a quantum processor based on trapped ions to the larger scientific community”
Susan Clark
QSCOUT Principal Investigator, Sandia National Laboratories
Critical Need
Quantum information processing has reached an inflection point transitioning from proof of principle scientific experiments to small noisy quantum processors. To accelerate this process, it is necessary to provide the scientific community with access to testbed systems that provide full specifications, enable low-level access to native gate implementations, make vertical integration approaches possible, and provide ways to fully specify the scheduling of gates. Access to noisy intermediate-scale quantum (NISQ) systems is needed to understand and optimize the noise properties, learn how to characterize and validate quantum operation, and to incubate the development and optimization of quantum algorithms for scientific applications.
The Quantum Scientific Computing Open User Testbed (QSCOUT) is a DOE program funded by the Office of Science’s Advanced Scientific Computing Research (ASCR) to build a quantum testbed based on trapped ions that is available to the research community. As an open platform, it will not only provide full specifications and control for the realization of all high- level quantum and classical processes, it will also enable researchers to investigate, alter, and optimize the internals of the testbed and test more advanced implementations of quantum operations.
Beginning of computation, each qubit prepared in |0〉 state of the z-basis
End of computation, entire quantum register is measured in z-basis
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QSCOUT Hardware
The QSCOUT hardware will be realized as a trapped ion system. A chain of ytterbium ions will be stored in a Sandia surface ion trap, which offers excellent optical access for state preparation, detection and qubit manipulations. Qubits are encoded in the hyperfine clock states of each ytterbium-171 ion and a chain of ions serves as the qubit register. Single- and multi-qubit operations are implemented with optical Raman transitions using a 355nm pulsed laser. Imaging of an acousto-optical modulator (AOM) array onto the ion chain is used to realize individual addressing of qubits in the register. At the end of a computation, the quantum state of each qubit in the register will be read out and reported for each qubit and each detection event. This is achieved with standard fluorescence detection by imaging the chain of ions on an array of multi-mode fibers connected to an array of individual photomultiplier tubes.
The Roadmap
We have a variety of features that are coming online soon including: Entangling gates for >2 ions and mid circuit measurements. We are also always working on higher fidelities and more qubits – stay tuned!
System characterization
The system will be characterized using validation and verification methods developed by Sandia’s Quantum Performance team. This will include characterizations of single and two-qubit gates using Gate Set Tomography (GST). Special attention will be made to reduce non-Markovian errors such as drifts and context-dependent gate errors. The results of these characterizations will be made available to users.
Pulse-level access
In addition to a standard Gate Level access, QSCOUT will enable users to propose and use alternate pulse shapes to realize gates or enable them to realize additional native gates by specifying the pulse sequence needed for their implementation.
Pulse sequences are realized using a custom multi-tone Direct Digital Synthesizer (DDS) system where the frequency, phase and amplitude modulations of all tones can be specified as spline functions.
Pulse sequences can be streamed out in real time and enable the user to run an unlimited number of gate sequences efficiently. Users are encouraged to develop gate implementations as pulse shapes in close collaboration with Sandia scientists who will implement the pulse shapes on the testbed system.
Jaqal™ the Quantum Assembly Language for QSCOUT
Just Another Quantum Assembly Language (Jaqal) is the programming language used to specify programs executed on QSCOUT. This document contains a specification of Jaqal along with a summary of QSCOUT 1.0 capabilities, for example, Jaqal programs, and plans for possible future extensions.
“Jaqal is a quantum programming language that forces the quantum computer to do exactly what you want, exactly when you want it. Or to put it another way, a language for micro-managing control freaks”
Andrew Landahl
QSCOUT software team lead, Sandia National Laboratories
