5 research outputs found
TISCC: A Surface Code Compiler and Resource Estimator for Trapped-Ion Processors
We introduce the Trapped-Ion Surface Code Compiler (TISCC), a software tool
that generates circuits for a universal set of surface code patch operations in
terms of a native trapped-ion gate set. To accomplish this, TISCC manages an
internal representation of a trapped-ion system where a repeating pattern of
trapping zones and junctions is arranged in an arbitrarily large rectangular
grid. Surface code operations are compiled by instantiating surface code
patches on the grid and using methods to generate transversal operations over
data qubits, rounds of error correction over stabilizer plaquettes, and/or
lattice surgery operations between neighboring patches. Beyond the
implementation of a basic surface code instruction set, TISCC contains corner
movement functionality and a patch translation that is implemented using ion
movement alone. Except in the latter case, all TISCC functionality is
extensible to alternative grid-like hardware architectures. TISCC output has
been verified using the Oak Ridge Quasi-Clifford Simulator (ORQCS).Comment: 10 pages, 5 figures. Software to be released at
https://github.com/ORNL-QCI/TISC
Control Requirements and Benchmarks for Quantum Error Correction
Reaching useful fault-tolerant quantum computation relies on successfully
implementing quantum error correction (QEC). In QEC, quantum gates and
measurements are performed to stabilize the computational qubits, and classical
processing is used to convert the measurements into estimated logical Pauli
frame updates or logical measurement results. While QEC research has
concentrated on developing and evaluating QEC codes and decoding algorithms,
specification and clarification of the requirements for the classical control
system running QEC codes are lacking. Here, we elucidate the roles of the QEC
control system, the necessity to implement low latency feed-forward quantum
operations, and suggest near-term benchmarks that confront the classical
bottlenecks for QEC quantum computation. These benchmarks are based on the
latency between a measurement and the operation that depends on it and
incorporate the different control aspects such as quantum-classical
parallelization capabilities and decoding throughput. Using a dynamical system
analysis, we show how the QEC control system latency performance determines the
operation regime of a QEC circuit: latency divergence, where quantum
calculations are unfeasible, classical-controller limited runtime, or
quantum-operation limited runtime where the classical operations do not delay
the quantum circuit. This analysis and the proposed benchmarks aim to allow the
evaluation and development of QEC control systems toward their realization as a
main component in fault-tolerant quantum computation.Comment: 21+9(SM) pages, 6+3(SM) figure
Real-Time Decoding for Fault-Tolerant Quantum Computing: Progress, Challenges and Outlook
Quantum computing is poised to solve practically useful problems which are
computationally intractable for classical supercomputers. However, the current
generation of quantum computers are limited by errors that may only partially
be mitigated by developing higher-quality qubits. Quantum error correction
(QEC) will thus be necessary to ensure fault tolerance. QEC protects the
logical information by cyclically measuring syndrome information about the
errors. An essential part of QEC is the decoder, which uses the syndrome to
compute the likely effect of the errors on the logical degrees of freedom and
provide a tentative correction. The decoder must be accurate, fast enough to
keep pace with the QEC cycle (e.g., on a microsecond timescale for
superconducting qubits) and with hard real-time system integration to support
logical operations. As such, real-time decoding is essential to realize
fault-tolerant quantum computing and to achieve quantum advantage. In this
work, we highlight some of the key challenges facing the implementation of
real-time decoders while providing a succinct summary of the progress to-date.
Furthermore, we lay out our perspective for the future development and provide
a possible roadmap for the field of real-time decoding in the next few years.
As the quantum hardware is anticipated to scale up, this perspective article
will provide a guidance for researchers, focusing on the most pressing issues
in real-time decoding and facilitating the development of solutions across
quantum and computer science
Pauli Frames for Quantum Computer Architectures
Quantum computers hold the promise to solve problems that are intractable to classical computers. Since qubits suffer from extremely short lifetime and unreliable operations, Quantum Error Correction (QEC) forms a vital part of a quantum computer to enable Fault-Tolerant quantum computing. The usage of a Pauli frame can relax the time constraints on QEC by keeping track of detected errors in classical logic. For the first time, in the background of a heterogeneous quantum computer architecture, we clarified the input/output and working principles of a Pauli frame, which can soon be mapped to a hardware implementation. We proposed the first functional quantum computer architecture simulation platform, QPDO, which can connect to different quantum simulators, such as QX Simulator or CHP, and is used to verify the logical operations of a Surface Code 17 (SC17) logical qubit. Finally, by using QPDO we found that a Pauli frame does not improve the Logical Error Rate (LER) of a SC17 logical qubit, which is opposite to previous understanding. By further reasoning, we also expect no improvement in LER by using a Pauli frame for surface codes with a larger distance. Nevertheless, the usage of a Pauli frame is still crucial for relaxing the timing constraints on QEC.Electrical Engineering, Mathematics and Computer ScienceComputer Engineerin