LILLIPUT: A Lightweight Low-Latency Lookup-Table Based Decoder for Near-term Quantum Error Correction

• URL: http://arxiv.org/abs/2108.06569v1
• Date: Sat, 14 Aug 2021 15:50:09 GMT
• Title: LILLIPUT: A Lightweight Low-Latency Lookup-Table Based Decoder for Near-term Quantum Error Correction
• Authors: Poulami Das, Aditya Locharla, Cody Jones
• Abstract summary: Quantum Error Correction (QEC) encodes logical qubits and distributes information using several physical qubits. LILLIPUT translates syndromes into error detection events that index into a Look-Up Table (LUT) whose entry provides the error information in real-time. LILLIPUT tolerates an error on any operation in the quantum hardware, including gates and measurement, and the number of tolerated errors grows with the size of the code.
• Score: 3.6532769050417997
• License: http://creativecommons.org/licenses/by/4.0/
• Abstract: The error rates of quantum devices are orders of magnitude higher than what is needed to run most quantum applications. To close this gap, Quantum Error Correction (QEC) encodes logical qubits and distributes information using several physical qubits. By periodically executing a syndrome extraction circuit on the logical qubits, information about errors (called syndrome) is extracted while running programs. A decoder uses these syndromes to identify and correct errors in real time, which is required to use feedback implemented in quantum algorithms. Unfortunately, software decoders are slow and hardware decoders are fast but less accurate. Thus, almost all QEC studies so far have relied on offline decoding. To enable real-time decoding in near-term QEC, we propose LILLIPUT-- a Lightweight Low Latency Look-Up Table decoder. LILLIPUT consists of two parts-- First, it translates syndromes into error detection events that index into a Look-Up Table (LUT) whose entry provides the error information in real-time. Second, it programs the LUTs with error assignments for all possible error events by running a software decoder offline. LILLIPUT tolerates an error on any operation in the quantum hardware, including gates and measurement, and the number of tolerated errors grows with the size of the code. It needs <7% logic on off-the-shelf FPGAs that allows it to be easily integrated alongside the control and readout circuits in existing systems. LILLIPUT incurs a latency of few nanoseconds and enables real-time decoding. We also propose Compressed LUTs (CLUTs) to reduce the memory needed by LILLIPUT. By exploiting the fact that not all error events are equally likely and only storing data for the most probable error events, CLUTs reduce the memory needed by up-to 107x (from 148 MB to 1.38 MB) without degrading accuracy.

Related papers

• Demonstrating real-time and low-latency quantum error correction with superconducting qubits [52.08698178354922]
  We demonstrate low-latency feedback with a scalable FPGA decoder integrated into a superconducting quantum processor. We observe logical error suppression as the number of decoding rounds is increased. The decoder throughput and latency developed in this work, combined with continued device improvements, unlock the next generation of experiments.
  arXiv  Detail & Related papers  (2024-10-07T17:07:18Z)
• Fault-Tolerant Belief Propagation for Practical Quantum Memory [6.322831694506286]
  A fault-tolerant approach to reliable quantum memory is essential for scalable quantum computing. We propose a decoder that utilizes a space-time Tanner graph across multiple rounds of syndrome extraction with mixed-alphabet error variables. Our simulations demonstrate high error thresholds of 0.4%-0.87% and strong error-floor performance for topological code families.
  arXiv  Detail & Related papers  (2024-09-27T12:21:45Z)
• Quantum error correction below the surface code threshold [107.92016014248976]
  Quantum error correction provides a path to reach practical quantum computing by combining multiple physical qubits into a logical qubit. We present two surface code memories operating below a critical threshold: a distance-7 code and a distance-5 code integrated with a real-time decoder. Our results present device performance that, if scaled, could realize the operational requirements of large scale fault-tolerant quantum algorithms.
  arXiv  Detail & Related papers  (2024-08-24T23:08:50Z)
• Algorithmic Fault Tolerance for Fast Quantum Computing [37.448838730002905]
  We show that fault-tolerant logical operations can be performed with constant time overhead for a broad class of quantum codes. We prove that the deviation from the ideal measurement result distribution can be made exponentially small in the code distance. Our work sheds new light on the theory of fault tolerance, potentially reducing the space-time cost of practical fault-tolerant quantum computation by orders of magnitude.
  arXiv  Detail & Related papers  (2024-06-25T15:43:25Z)
• Ambiguity Clustering: an accurate and efficient decoder for qLDPC codes [0.0]
  We introduce Ambiguity Clustering (AC), an algorithm which seeks to divide measurement data into clusters which are decoded independently. AC is between one and three orders of magnitude faster than BP-OSD with no reduction in logical fidelity. Our CPU implementation of AC is already fast enough to decode the 144-qubit Gross code in real time for neutral atom and trapped ion systems.
  arXiv  Detail & Related papers  (2024-06-20T17:39:31Z)
• Deep Quantum Error Correction [73.54643419792453]
  Quantum error correction codes (QECC) are a key component for realizing the potential of quantum computing. In this work, we efficiently train novel emphend-to-end deep quantum error decoders. The proposed method demonstrates the power of neural decoders for QECC by achieving state-of-the-art accuracy.
  arXiv  Detail & Related papers  (2023-01-27T08:16:26Z)
• Overcoming leakage in scalable quantum error correction [128.39402546769284]
  Leakage of quantum information out of computational states into higher energy states represents a major challenge in the pursuit of quantum error correction (QEC) Here, we demonstrate the execution of a distance-3 surface code and distance-21 bit-flip code on a Sycamore quantum processor where leakage is removed from all qubits in each cycle. We report a ten-fold reduction in steady-state leakage population on the data qubits encoding the logical state and an average leakage population of less than $1 times 10-3$ throughout the entire device.
  arXiv  Detail & Related papers  (2022-11-09T07:54:35Z)
• Matching and maximum likelihood decoding of a multi-round subsystem quantum error correction experiment [1.2189422792863451]
  We perform quantum error correction on superconducting qubits connected in a heavy-hexagon lattice. Full processor can encode a logical qubit with distance three and perform several rounds of fault-tolerant syndrome measurements. We show that the logical error varies depending on the use of a perfect matching decoder.
  arXiv  Detail & Related papers  (2022-03-14T15:44:11Z)
• Improved decoding of circuit noise and fragile boundaries of tailored surface codes [61.411482146110984]
  We introduce decoders that are both fast and accurate, and can be used with a wide class of quantum error correction codes. Our decoders, named belief-matching and belief-find, exploit all noise information and thereby unlock higher accuracy demonstrations of QEC. We find that the decoders led to a much higher threshold and lower qubit overhead in the tailored surface code with respect to the standard, square surface code.
  arXiv  Detail & Related papers  (2022-03-09T18:48:54Z)
• Exponential suppression of bit or phase flip errors with repetitive error correction [56.362599585843085]
  State-of-the-art quantum platforms typically have physical error rates near $10-3$. Quantum error correction (QEC) promises to bridge this divide by distributing quantum logical information across many physical qubits. We implement 1D repetition codes embedded in a 2D grid of superconducting qubits which demonstrate exponential suppression of bit or phase-flip errors.
  arXiv  Detail & Related papers  (2021-02-11T17:11:20Z)
• A Scalable Decoder Micro-architecture for Fault-Tolerant Quantum Computing [2.617437465051793]
  We design a decoder micro-architecture for the Union-Find decoding algorithm. We optimize the amount of decoding hardware required to perform error correction simultaneously over all the logical qubits of the quantum computer.
  arXiv  Detail & Related papers  (2020-01-18T04:44:52Z)

This list is automatically generated from the titles and abstracts of the papers in this site.

This site does not guarantee the quality of this site (including all information) and is not responsible for any consequences.