arXiv subjects

Ameya S. Bhave

Publications and source records attributed to Ameya S. Bhave.

3 recordsLinked to original sources

arXiv2026

DART-Q : A Deadline-Driven Framework for Real-Time QLDPC Decoding

Real-time quantum error correction places the classical decoder inside the fault-tolerant control loop under strict timing and memory constraints. For quantum low-density parity-check (QLDPC) codes, practical deployment therefore depends not only on correction performance, but also on timely decoding under deadlines, finite on-chip memory, and time-varying load. However, existing decoder studies primarily emphasize correction performance without exposing operational viability under these constraints. We present DART-Q, a real-time QLDPC decoding framework that treats windowed workloads as discrete arrival, queueing, service, and completion events. DART-Q models each decode request as a deadline-driven online service job with queueing and non-preemptive Earliest Deadline First scheduling. It supports configurable admission control, service times, and bounded rescue policies. Through controlled studies of the SRAM-fit transition, tail latency, overload, and a capacity-scaling extension, DART-Q isolates the effects of memory pressure, rescue selectivity, admission control, and pooled service capacity on timely decoding. Our results show that real-time decoder viability is governed by state organization, overload policy, and service capacity. A cached-summary state organization lowers the SRAM-fit boundary by 4x relative to an edge-centric baseline. Under overload, relaxing the backlog cap increases queued work by approximately 20.1x and worsens p99 latency by approximately 17.6x, with little gain in useful throughput. In contrast, doubling decoder capacity reduces the MissRate from 97.64% to 0.98% and improves p99 latency from 3.861ms to 10$μ$s. These results position DART-Q as a framework for exposing the regime changes that determine real-time QLDPC decoder viability under deadlines, finite memory, and time-varying load.

quant-ph↗

arXiv2026

BiBiEQ: Bivariate Bicycle Codes on Erasure Qubits

Erasure qubits reduce overhead in fault-tolerant quantum error correction (QEC) by converting dominant faults into detectable errors known as erasures. They have demonstrated notable improvements in thresholds and scaling in surface and Floquet code memories. In this work, we use erasure qubits on Bivariate Bicycle (BB) codes from the quantum low-density parity-check (QLDPC) regime. Owing to their sparse structure and favorable rate-distance trade-offs, BB codes are practical candidates for QEC. We introduce BiBiEQ, a novel framework that compiles a given BB code into an erasure-aware memory circuit C_E. This erasure circuit C_E comprises erasure checks (ECs), resets, and erasures spread over a user-specified erasure check schedule (2EC, 4EC). BiBiEQ converts this erasure circuit C_E into the stabilizer circuit C for general-purpose decoding. BiBiEQ provides two engines for this conversion, BiBiEQ-Exact and BiBiEQ-Approx. BiBiEQ-Exact preserves the joint-erasure correlations and serves as our accuracy benchmark, while BiBiEQ-Approx uses an independence approximation to accelerate large sweeps and expose accuracy-throughput trade-offs. Using BiBiEQ, we decode the stabilizer circuits to get a per-round logical error rate (LER) for the BB codes and quantify the effect of the EC schedules on the correctable operating region below the pseudo-threshold. The 4EC schedule keeps the accuracy of both engines close to one another, making BiBiEQ-Approx a reliable proxy for BiBiEQ-Exact for faster sweeps. Below the pseudo-threshold, the code distance (d) hop from distance (d) 6 to 10 yields a drop in LER by 10-17x larger than distance (d) 10 to 12, showing that most gains are realized by d=10.

quant-ph↗

arXiv2025

HyperNQ: A Hypergraph Neural Network Decoder for Quantum LDPC Codes

Quantum computing requires effective error correction strategies to mitigate noise and decoherence. Quantum Low-Density Parity-Check (QLDPC) codes have emerged as a promising solution for scalable Quantum Error Correction (QEC) applications by supporting constant-rate encoding and a sparse parity-check structure. However, decoding QLDPC codes via traditional approaches such as Belief Propagation (BP) suffers from poor convergence in the presence of short cycles. Machine learning techniques like Graph Neural Networks (GNNs) utilize learned message passing over their node features; however, they are restricted to pairwise interactions on Tanner graphs, which limits their ability to capture higher-order correlations. In this work, we propose HyperNQ, the first Hypergraph Neural Network (HGNN)- based QLDPC decoder that captures higher-order stabilizer constraints by utilizing hyperedges-thus enabling highly expressive and compact decoding. We use a two-stage message passing scheme and evaluate the decoder over the pseudo-threshold region. Below the pseudo-threshold mark, HyperNQ improves the Logical Error Rate (LER) up to 84% over BP and 50% over GNN-based strategies, demonstrating enhanced performance over the existing state-of-the-art decoders.

cs.LG↗