QuMod: Parallel Quantum Job Scheduling on Modular QPUs using Circuit Cutting
Vinooth Kulkarni, Aaron Orenstein, Xinpeng Li, Shuai Xu, Daniel Blankenberg, Vipin Chaudhary
Abstract
The quantum computing community is increasingly positioning quantum processors as accelerators within classical HPC workflows, analogous to GPUs and TPUs. However, many real-world applications require scaling to hundreds or thousands of physical qubits to realize logical qubits via error correction. To reach these scales, hardware vendors employing diverse technologies -- such as trapped ions, photonics, neutral atoms, and superconducting circuits -- are moving beyond single, monolithic QPUs toward modular architectures connected via interconnects. For example, IonQ has proposed photonic links for scaling, while IBM has demonstrated a modular QPU architecture by classically linking two 127-qubit devices. Using dynamic circuits, Bell-pair-based teleportation, and circuit cutting, they have shown how to execute a large quantum circuit that cannot fit on a single QPU. As interest in quantum computing grows, cloud providers must ensure fair and efficient resource allocation for multiple users sharing such modular systems. Classical interconnection of QPUs introduces new scheduling challenges, particularly when multiple jobs execute in parallel. In this work, we develop a multi-programmable scheduler for modular quantum systems that jointly considers qubit mapping, parallel circuit execution, measurement synchronization across subcircuits, and teleportation operations between QPUs using dynamic circuits.
AI Impact Assessments
(3 models)Scientific Impact Assessment: QuMod: Parallel Quantum Job Scheduling on Modular QPUs using Circuit Cutting
1. Core Contribution
QuMod proposes a parallel quantum job scheduler for modular quantum processing unit (QPU) architectures that integrates circuit cutting with two operational modes: Local Operations (LO) and Local Operations with Classical Communication (LOCC). The scheduler jointly handles qubit mapping, parallel circuit execution, measurement synchronization across subcircuits, and teleportation operations between QPUs. The key novelty lies in combining multi-programming scheduling (running multiple quantum jobs in parallel) with adaptive circuit cutting decisions on modular, classically-interconnected QPU systems. The scheduler dynamically decides whether and how to cut circuits, grouping upstream and downstream subcircuits while respecting causal ordering constraints imposed by LOCC's feed-forward requirements.
2. Methodological Rigor
The paper presents algorithms for scheduling (Algorithm 1), circuit cutting mode selection (Algorithm 2), and grouping with LO/LOCC constraints (Algorithm 3). The formalization of feasibility constraints (Equation 4), cost functions (Equations 5-7), and slot computation (Equation 8) provides a reasonable mathematical framework.
However, the evaluation has significant limitations:
3. Potential Impact
The problem addressed—scheduling quantum jobs on modular QPU architectures—is genuinely important for the future of quantum cloud computing. As vendors like IBM, IonQ, and others move toward modular designs, schedulers that understand circuit cutting tradeoffs will become essential infrastructure.
However, the immediate practical impact is limited because:
4. Timeliness & Relevance
The paper is timely in the sense that modular quantum computing is an active research direction, and IBM's 2024 Nature demonstration of classically-linked QPUs validates the general premise. The quantum cloud scheduling problem will indeed become more important as quantum computing matures.
However, the paper arrives at an awkward time—modular architectures are still too early-stage for the scheduling problem to be practically pressing, yet the theoretical framework presented is not deep enough to provide lasting algorithmic insights.
5. Strengths & Limitations
Strengths:
Limitations:
Overall Assessment
QuMod addresses a valid problem in quantum systems research and presents a reasonable first-cut solution for scheduling on modular QPU architectures. However, the evaluation is too limited to convincingly demonstrate the approach's benefits, the lack of baselines beyond self-comparison (LO vs. LOCC) weakens the contribution, and the work appears incremental over the authors' prior scheduling papers. The paper would benefit substantially from hardware validation (even on IBM's two-QPU system), stronger baselines, and deeper analysis of the scheduling quality-fidelity tradeoff.
Generated Apr 14, 2026
Comparison History (43)
Paper 1 addresses a critical systemic bottleneck in quantum computing scalability: managing and scheduling resources across modular Quantum Processing Units (QPUs). As hardware vendors pivot to modular architectures to scale towards fault tolerance, effective job scheduling, circuit cutting, and interconnect management become essential. This systems-level contribution has broad implications for integrating quantum accelerators into classical HPC workflows. Paper 2 offers a practical but narrower data-processing optimization specifically for near-term quantum machine learning, limiting its overall infrastructural impact compared to Paper 1.
Paper 2 introduces a simple, broadly applicable technique (split-ensemble training) that improves near-term quantum machine learning without additional hardware cost. Its practical applicability across existing quantum hardware and algorithmic generality give it immediate impact. Paper 1 addresses an important but narrower scheduling problem for modular QPUs—a relevant engineering contribution, but its impact is constrained to a specific architectural paradigm still under development. Paper 2's low barrier to adoption, hardware validation, and relevance to the large near-term quantum computing community give it higher potential impact.
Paper 1 establishes a fundamental theoretical result about the light-cone structure of entanglement propagation, providing rigorous bounds applicable to a wide class of quantum systems. This type of foundational result in quantum information theory has broad and lasting impact across quantum computing, quantum networks, and condensed matter physics. Paper 2 addresses a practical but narrower engineering problem of scheduling quantum jobs on modular QPUs. While timely and useful, it represents an incremental contribution to quantum systems engineering rather than a fundamental advance with cross-disciplinary impact.
Paper 1 targets a near-term, high-leverage systems bottleneck: scheduling and resource allocation for modular, multi-user quantum accelerators, integrating mapping, synchronization, teleportation, and circuit cutting. This is timely given active vendor roadmaps toward modular QPUs and cloud/HPC integration, and its ideas can influence runtime stacks across platforms, benefiting many applications. Paper 2 is rigorous and valuable for fault-tolerant resource theory, but its impact is narrower (specific diagonal quadratic operators and encoding tradeoffs) and more contingent on future qudit hardware/compiler advances.
Paper 1 presents a rigorous theoretical advancement combining multilevel Monte Carlo methods with randomized Hamiltonian simulation, achieving a provable complexity improvement from O(ε⁻³) to O(ε⁻²log²(1/ε)). This addresses a fundamental bottleneck in quantum simulation with broad applicability across quantum chemistry, materials science, and quantum algorithms. The novelty of bridging MLMC with quantum computing is significant. Paper 2 addresses practical scheduling for modular QPUs, which is important engineering work but is more incremental and narrower in scope, focused on near-term system management rather than foundational algorithmic advances.
Paper 1 likely has higher scientific impact due to strong novelty and rigor: it provides optimal (tight) query complexities across three access models and establishes a strict hierarchy, resolving/settling complexity questions by matching known lower bounds. This is a clear theoretical milestone with durable relevance to quantum algorithms, property testing, and channel verification. Paper 2 targets an important applied systems problem (scheduling on modular QPUs) with near-term relevance, but impact depends more on engineering validation, benchmarks, and adoption; its conceptual advance appears less fundamental and may be superseded by hardware/platform-specific solutions.
Paper 2 likely has higher impact due to broader applicability and timeliness: scheduling and resource management for modular, cloud-accessible QPUs is a near-term bottleneck across hardware platforms. Its contributions (multi-job scheduling with mapping, synchronization, dynamic-circuit teleportation, and circuit cutting) can influence quantum OS/compilers, HPC integration, and cloud operations, affecting many users and vendors. Paper 1 is methodologically rigorous and valuable for fluxonium scalability, but its impact is narrower (specific hardware stack and coupler choice) and depends more on experimental adoption of DTC-based fluxonium architectures.
Paper 2 likely has higher scientific impact because it directly challenges a timely claim of heuristic quantum advantage with a concrete, efficient classical simulation method, potentially reshaping benchmarks and verification practices across quantum computing. Its approach (exploiting circuit structure, MPO cancellation, and “unswapping”) is a clear algorithmic contribution with immediate applicability to evaluating advantage experiments and designing more robust circuits. While Paper 1 addresses an important systems problem (scheduling for modular QPUs), its impact is more incremental and contingent on widespread modular-hardware deployment.
Paper 2 addresses a highly timely and critical bottleneck in scaling quantum computing: resource scheduling across modular QPUs. Its focus on integrating quantum processors into cloud and HPC workflows using practical techniques like circuit cutting provides broad, immediate applicability for major hardware vendors and cloud providers. While Paper 1 offers valuable theoretical insights into waveguide QED, Paper 2 has a significantly wider breadth of impact across computer science, quantum architecture, and systems engineering, making it more likely to drive real-world technological advancements.
Paper 2 addresses a critical systems-level bottleneck in scaling quantum computers by proposing a scheduling framework for modular QPUs. Its hardware-agnostic approach applies across various technologies (superconducting, trapped ions, etc.) and tackles practical challenges in cloud resource allocation, giving it broader real-world applicability. Paper 1 is highly innovative but its impact is constrained specifically to neutral atom architectures.
Paper 2 likely has higher near-term scientific impact due to strong timeliness and clear real-world applicability: scheduling and resource management for modular, cloud-accessible QPUs is an immediate bottleneck as systems scale beyond single devices. It integrates circuit cutting, teleportation, dynamic circuits, mapping, and synchronization into an HPC-style scheduler, potentially influencing both systems research and practical deployments across vendors. Paper 1 is mathematically novel and foundational (universality of time-independent impurity Hamiltonians), but its impact may be narrower and longer-term, with less direct path to deployment.
Paper 1 introduces novel theoretical metrics (QCM, QCF, QCC) for characterizing quantum network connectivity, addressing a fundamental gap between classical topological metrics and actual quantum functionality. This provides broadly applicable tools for the entire quantum networking community. The insight that fully connected graphs can be functionally disconnected for quantum tasks is particularly impactful. Paper 2 addresses an important but more narrowly scoped engineering problem of job scheduling on modular QPUs. While practical, it is more incremental, combining existing techniques (circuit cutting, teleportation) into a scheduling framework with more limited theoretical contribution.
Paper 2 is more novel and broadly impactful: it proposes a formal link between Born-rule sampling and Bayesian posterior uncertainty, positioning quantum measurement as a principled UQ mechanism for physics-constrained learning. This spans quantum ML, uncertainty quantification, and scientific ML/PDE modeling, with timely relevance to trustworthy AI. It also presents comparative experiments and theoretical analysis. Paper 1 addresses an important systems problem (scheduling for modular QPUs) with clear practical value, but its impact is narrower (quantum systems/HPC scheduling) and more incremental relative to existing modular execution/circuit cutting work.
Paper 1 addresses a critical and immediate bottleneck in quantum computing: scaling up processors via modular architectures and integrating them into classical HPC workflows. Its focus on multi-programmable scheduling and resource allocation offers immense practical value and near-term real-world applications for cloud providers and hardware vendors. While Paper 2 presents interesting foundational work in quantum sensing, Paper 1's timely solutions to systems-level scaling challenges provide a broader and more immediate impact on the rapid development and deployment of practical quantum computers.
Paper 1 targets a near-term, well-defined bottleneck in scalable quantum computing: scheduling and resource management for modular QPUs with circuit cutting/teleportation and dynamic circuits. It has clear real-world applicability for cloud/HPC quantum services, is timely given active modular-hardware roadmaps, and can influence systems research, compilers, and quantum control. Paper 2 is ambitious and potentially profound, but reads as highly speculative theoretical unification with unclear empirical validation and higher risk of limited uptake. Overall, Paper 1 is more likely to yield actionable, broadly adopted results soon.
Paper 1 targets a timely, high-need systems problem for scaling quantum computing: scheduling and resource allocation on modular QPUs with circuit cutting/teleportation and dynamic-circuit constraints. If validated, it enables higher utilization, fairness, and throughput for multi-user quantum cloud/HPC workflows, with broad impact across quantum architectures and quantum/classical systems research. Paper 2 is conceptually striking and relevant to foundations/quantum imaging, but its applications are narrower and it likely advances understanding more than it unlocks scalable technology. Overall, Paper 1 has greater expected cross-field and practical impact.
Paper 2 addresses a critical and immediate bottleneck in quantum computing: scaling through modular QPUs. By introducing a novel multi-programmable scheduler that handles circuit cutting and teleportation, it provides a foundational systems-level innovation for quantum cloud infrastructure. While Paper 1 offers a valuable comprehensive review, Paper 2 proposes a concrete technical solution to an active engineering challenge, which is highly likely to spur extensive follow-up research in quantum computer architecture and HPC integration.
Paper 1 addresses a fundamental and notoriously difficult theoretical problem in quantum simulation: handling the unbounded and singular nature of Coulomb interactions. By providing rigorous error bounds and polynomial scaling for Trotterization, it significantly advances quantum chemistry and physics applications, which are considered the most promising near-term use cases for quantum computers. While Paper 2 offers a practical systems-level solution for modular QPUs, Paper 1 provides foundational mathematical guarantees that will durably impact the core algorithmic theory of quantum simulation across multiple disciplines.
Paper 1 addresses a critical and immediate bottleneck in scaling quantum computers: resource scheduling across modular QPUs. This has direct, broad implications for integrating quantum accelerators into HPC and cloud environments, aligning perfectly with current industry scaling efforts. While Paper 2 offers an innovative application of TDA to quantum thermodynamics, its focus on finite-time quantum heat engines is comparatively niche, limiting its near-term real-world impact relative to the foundational systems-level advancements proposed in Paper 1.
Paper 1 offers a theoretically grounded advance on a central bottleneck in variational quantum algorithms (barren plateaus), introducing a provably safe, adaptive expressibility expansion with explicit gradient-variance bounds and supporting empirical benchmarks with strong statistical significance. This combination of novelty (rigorous trajectory through trainability–expressibility), methodological rigor (theorems/lemmas + controlled experiments), and broad relevance to near-term quantum algorithms suggests high cross-field impact (quantum algorithms, optimization, physics-inspired ML). Paper 2 is timely and practically important for modular QPU operations, but appears more systems-engineering with less clear foundational novelty from the abstract alone.