qubit-os

Overview

QubitOS is an open-source real-time kernel for quantum pulse optimization and hardware control. The project provides a production-grade infrastructure layer for quantum experiments, bridging the gap between high-level circuit descriptions and hardware-specific pulse sequences.

Key Design Goals:

• Deterministic, reproducible pulse optimization
• Backend independence (simulators and real hardware)
• Strict protocol contracts via Protocol Buffers
• Science-aware validation via AgentBible integration

Current Implementation Status

Key Results

Architecture

                           User Layer
   CLI (qubit-os) | Jupyter Notebooks | Python Scripts
                              |
              +---------------+---------------+
              |                               |
              v                               v
+-------------------------+     +-------------------------+
|   Pulse Optimization    |     |  Calibration Management |
|   (qubitos.pulsegen)    |     |  (qubitos.calibrator)   |
|   - GRAPE optimizer     |     |  - T1/T2 fitting        |
|   - DRAG pulses         |     |  - Fingerprinting       |
|   - Validation          |     |  - Policy enforcement   |
+------------+------------+     +------------+------------+
             |                               |
             +---------------+---------------+
                             | gRPC
                             v
               +-------------------------+
               |  Hardware Abstraction   |
               |  Layer (HAL)            |
               |  - Rust + tonic         |
               |  - Backend registry     |
               |  - Request validation   |
               +------------+------------+
                            |
            +---------------+---------------+
            |               |               |
            v               v               v
      +----------+   +----------+   +----------+
      |  QuTiP   |   |   IQM    |   |  Future  |
      | Backend  |   | Backend  |   | Backends |
      +----------+   +----------+   +----------+

Implementation Highlights

Protocol Buffers (qubit-os-proto)

• 7 proto files defining the complete API contract
• Message types: PulseShape, GateType, HamiltonianSpec, ExecutePulseRequest/Response
• QuantumBackendService gRPC service with 5 RPCs
• Python and Rust code generation via buf.gen.yaml

Rust HAL Server (qubit-os-hardware)

• 17 source files implementing the hardware abstraction layer
• gRPC server using tonic 0.12
• REST API facade using axum 0.7
• QuTiP Backend: Full implementation with PyO3 integration
  • mesolve() time evolution
  • Proper tensor product dimension handling
  • State vector extraction
• Backend registry with health checks
• Input validation and security (error message sanitization)

Python Library (qubit-os-core)

• 48 source files (including generated protos)
• GRAPE Optimizer (568 lines): Full gradient ascent pulse engineering with Adam-style adaptive learning rate
• HAL Client: Async + sync wrappers for gRPC
• Calibration System: YAML schema with fingerprinting, drift detection
• Validation Framework: Hermitian/unitary matrix validation, fidelity range checking
• CLI: qubit-os command with subcommands

Supported Operations (v0.1-alpha target)

Backends

• QuTiP Simulator: Default offline backend using Lindblad master equation
• IQM Garnet: Cloud hardware backend (20-qubit superconducting processor) — Phase 3

Roadmap

Design Principles

1. Single Responsibility - Each module has one well-defined job
2. Strict Contracts - All inter-module communication uses versioned protos
3. Backend Independence - Backends implement a common trait; no special-casing
4. Reproducibility First - Every result traces to code version, seed, and calibration
5. Fail Loud - Clear error semantics; no silent failures
6. Science-Aware Validation - Domain validators catch physics errors early

Technology Stack

Integration with Existing Work

QubitOS builds on my previous quantum projects:

• QubitPulseOpt: GRAPE optimization algorithms
• quantum-circuit-optimizer: Circuit compilation
• qco-integration: End-to-end fidelity analysis
• AgentBible: Scientific validation framework

Links

• GitHub Repository
• Design Document (v0.5.0)

License

Apache 2.0 - Keeping fundamental quantum experimentation open and non-proprietary.