SchroSIM

SchroSIM is a continuous-variable (CV) photonic quantum simulation stack for designing, compiling, and simulating hardware-like photonic quantum circuits. The open-source core combines an SDK for developer integration and a CLI for terminal-based circuit execution.

Built for students, researchers, and quantum foundry engineers, SchroSIM provides an exact-solution simulation path for tractable circuits and scalable backend options for larger workflows.

Documentation: Full project documentation is in SchroSIM Docs.

"SchroSIM core (compiler, runtime, SDK/CLI, docs, and public examples) is open source under MIT for research, education, and downstream studies. Enterprise-only capabilities (advanced UI, partner-specific integrations, and commercialization-focused IP) are developed in enterprise mode and are intended to live in a separate private distribution path. This boundary keeps reproducible scientific workflows public while allowing confidential enterprise delivery for hardware and industrial partners."

The enterprise UI is focused on:

1. project-scoped circuit workflows,
2. backend-aware execution policies,
3. analysis views for simulation and QEC outcomes.

Status: enterprise-track active development.

The Need

Photonic and CV workflows need fast iteration across modeling, backend selection, and error-correction validation. In practice, teams often lose time moving between disconnected tools for design, compilation, execution, and debugging.

SchroSIM is built to make those workflows practical in one platform, with reproducible runs and backend-aware execution policies that support both research and pre-hardware validation.

Circuit and Runtime Failure Modes (Why They Matter)

The failure modes below are workflow-level circuit/runtime issues common in photonic and CV pipelines. They are not, by default, indicators of defects in SchroSIM itself.

Even promising photonic circuit designs can fail at compile time or simulation time. Common failure modes include:

1. non-physical parameter sets (invalid squeezing ranges, inconsistent phase settings, or state assumptions),
2. backend/model mismatch (idealized circuits mapped to noisy or hardware-constrained targets without adaptation),
3. numerical limits (insufficient cutoff dimensions, precision issues, or unstable optimization settings),
4. hardware-like constraints (unsupported operations, timing/order conflicts, and foundry policy limits).

SchroSIM helps surface these issues early with backend-aware checks, reproducible runtime configuration, and analysis views that explain where and why execution failed.

Model-Exact Scope

SchroSIM provides model-exact simulation for tractable Gaussian CV workloads under the stated model assumptions. For larger, non-Gaussian-heavy, or more hardware-constrained cases, SchroSIM supports backend-aware execution paths that use controlled approximations for scalability and runtime practicality.

Use this rule of thumb:

1. use the model-exact Gaussian path for ground-truth studies, validation, and small-to-mid scale circuit analysis,
2. use scalable/hybrid/Fock policy-targeted paths as controlled approximations for larger experiments and pre-hardware iteration.

Design-to-Result Workflow

1. define a circuit in project JSON (public workflow) or design it in the enterprise UI (private track),
2. compile to backend-aware intermediate/runtime configuration,
3. run static checks for operation support and constraint compatibility,
4. execute simulation on selected path (model-exact Gaussian or controlled approximation backend path),
5. analyze observables, runtime metrics, and QEC outcomes,
6. iterate parameters, backend, and correction strategy with reproducible settings.

Failure Diagnostics in SchroSIM

Failure class	Typical symptom	Likely cause	Mitigation
Non-physical parameters	compile rejection or invalid state warning	squeezing/phase/state assumptions outside valid region	enforce parameter bounds and validate state configuration before execution
Backend mismatch	operator unsupported or policy violation	circuit authored for ideal model but run on constrained target	remap operations to backend-supported primitives and recompile
Numerical instability	divergent metrics or inconsistent repeated results	cutoff too small, unstable optimizer, precision loss	increase cutoff, tune solver/optimizer settings, fix deterministic seeds
Resource overrun	excessive runtime/memory	circuit scale exceeds selected method limits	switch backend mode, reduce circuit depth/modes, profile bottlenecks
Constraint conflict	schedule/order/timing failure	gate ordering violates foundry/runtime constraints	use compiler ordering hints and backend-specific scheduling policies

Hardware-Like and Foundry Constraints

SchroSIM is built for pre-hardware realism. Backend-aware compilation and runtime policy checks help teams identify unsupported operations, ordering constraints, and integration risks before tape-out or hardware queue submission.

Numerical Reliability and Reproducibility

For technical studies, use fixed seeds, pinned runtime configuration, and explicit cutoff/precision settings. This makes experiments repeatable and simplifies regression checks across backend changes.

Project Maturity

SchroSIM is under active development. Core workflows for circuit design, compilation, execution, and analysis are available, with ongoing expansion of backend coverage and diagnostics depth.

Toolchain Prerequisites

SchroSIM source workflows require Python, Swift, and Rust toolchains.

Verify your environment:

python3 --version
pip --version
swift --version
rustc --version
cargo --version

Quick Start

For the published Python package:

pip install schrosim
schrosim --help

The Python package provides the schrosim launcher and helper entry points. When run inside a source checkout (with Swift installed), it delegates to schrosim-cli.

For this source repository:

swift run schrosim-cli --help

Python 3 is required for helper scripts and packaging workflows.

CLI: Run Demos

Run Boson Sampling:

schrosim run examples/runtime_default_foundry.json --backend hybrid

Run Quantum Error Correction:

schrosim run examples/cv/qec_single_logical_gkp_memory_mvp.json --backend hybrid

Optional: Run from CLion

CLion is recommended for contributor workflows (debugging, stepping through code, and managing run configurations). Keep CLI commands as the primary execution path for reproducible runs and CI alignment.