Monthly collaborative coding challenges from Quantum Collective — a 900+ member quantum computing community based in India.
Build real quantum tools. Learn by shipping.
Discord · WhatsApp · LinkedIn · YouTube
Quantum-Collective-Monthly-Projects/
│
├── 2026-05-circuit-simulator/ ← June 2026: Quantum Circuit Simulator (LIVE)
│ ├── qcsim/ ← Full reference implementation
│ │ ├── qcsim/ ← Core simulator source code
│ │ ├── examples/ ← Runnable examples (Bell, GHZ, Grover, etc.)
│ │ ├── tests/ ← 124 tests
│ │ ├── docs/adding-gates.md ← How to add new gates
│ │ └── README.md ← Full qcsim documentation
│ ├── circuit-library/ ← Community-submitted circuits
│ │ ├── examples/ ← Verified circuits (Bell, GHZ, etc.)
│ │ ├── search.py ← Search circuits by name/tags/difficulty
│ │ ├── add_circuit.py ← Submit your circuit
│ │ └── CONTRIBUTING-CIRCUITS.md ← How to submit circuits
│ ├── EXAMPLES.md ← Expected API patterns
│ └── README.md ← Challenge description + what to build
│
├── 2026-06-algorithm-visualizer/ ← July 2026: Quantum Algorithm Visualizer (LIVE)
│ └── qviz/ ← Reference implementation (depends on qcsim)
│
├── 2026-08-noise-simulator/ ← August 2026: Noisy Quantum Simulator (LIVE)
│ ├── qnoise/ ← Reference implementation (depends on qcsim)
│ │ ├── qnoise/ ← Engine: density matrix, channels, model, metrics
│ │ ├── examples/ ← Runnable examples (noisy Bell, sweep, custom model)
│ │ ├── tests/ ← 84 tests (incl. noise-off parity with qcsim)
│ │ └── docs/ ← Architecture, Channel-Development, Roadmap, API
│ └── README.md ← Challenge description + what to build
│
├── docs/
│ └── FAQ.md ← Frequently asked questions
│
├── CHANGELOG.md ← What changed and when
├── SECURITY.md ← How to report vulnerabilities
├── CONTRIBUTING.md ← How to participate and submit
└── README.md ← This file
Prefer a single launcher? From the repo root:
python hub.pyPick a product from the menu, use it, and land back at the menu when it exits — navigate between the circuit simulator, algorithm visualizer, and noise simulator without remembering three separate commands. The hub shows which tools are installed and prints the install steps for any that aren't.
A full quantum circuit simulator with an interactive visual builder and community circuit library.
Try it now — 3 commands:
git clone https://github.com/LochanPS/Quantum-Collective-Monthly-Projects.git
cd Quantum-Collective-Monthly-Projects/2026-05-circuit-simulator/qcsim
pip install -e . && qcsim-interactiveWhat's inside:
| Feature | Description |
|---|---|
| 🎮 Interactive TUI | Build circuits visually — no coding needed, up to 15 qubits |
| 🔗 25+ Gates | H, X, SXdg, CNOT, SWAP, Rx, Ry, Rz, Toffoli and more |
| 📊 Live Metrics | Depth, gate count, T-gate cost, entanglement |
| 🔍 Pattern Recognition | Recognizes Bell state, GHZ, and other known circuits |
| 📚 Circuit Library | Searchable community circuits |
| 🐍 Python API | Clean method chaining, Qiskit-compatible |
| 💪 Dual Backends | Kronecker (readable) + Tensor (scales to 20+ qubits) |
| 📤 Code Export | Export as Qiskit .py, OpenQASM 2.0/3.0, Cirq, or Quil — run on IBM Quantum, Cirq, Braket, Rigetti |
| ✅ Tested | 124 passing tests, Qiskit-compatible output |
Jump straight to:
- → Full documentation — API, TUI guide, architecture
- → Add a gate — Contribute new gates
- → Submit a circuit — Add to library
- → Circuit library — Browse community circuits
- → Challenge description — What to build + feature ideas
Step through a quantum algorithm one gate at a time and watch the state vector evolve — instead of only seeing the final answer. Built on top of qcsim (imports it as a library), terminal-only.
Try it now:
git clone https://github.com/LochanPS/Quantum-Collective-Monthly-Projects.git
cd Quantum-Collective-Monthly-Projects/2026-06-algorithm-visualizer/qviz
pip install -e ../../2026-05-circuit-simulator/qcsim # install qcsim first
pip install -e . && qviz-stepAlready have the repo (or an older qcsim)? Pull and refresh both editable installs:
cd Quantum-Collective-Monthly-Projects && git pull origin main
cd 2026-06-algorithm-visualizer/qviz
pip install -e ../../2026-05-circuit-simulator/qcsim # refresh qcsim
pip install -e . # refresh qviz
git pullalone picks up source edits (both packages install with-e); re-run the installs if entry points or dependencies changed. Ifqviz-stepisn't found afterward, re-runpip install -e ..
What's inside:
| Feature | Description |
|---|---|
| ⏯️ Step-through engine | Replay any circuit gate-by-gate, snapshot state at every step |
| 🧮 Core four algorithms | QFT, Grover, Deutsch-Jozsa, Bernstein-Vazirani — purpose-annotated per gate |
| 🧭 Phased walkthrough | Preparation → Oracle → Diffusion progress bar, windowed circuit, plain-English state reading |
| 🎯 Measurement + summary | Sampled measurement histogram, then measured-vs-expected success/fail verdict |
| ⌨️ Interactive CLI | Step/back/jump/autoplay, Beginner ↔ Advanced modes, menu loop |
| 🧩 Extensible by design | Clear contributor tiers (Beginner → Expert) — add algorithms, views, and more |
| ✅ Tested | 54 passing tests, including non-palindromic bitstring cases |
Jump straight to:
- → Challenge description — What to build + contribution tiers
- → Package README — Usage, API, quick start
- → Documentation index — Architecture, Developer Guide, Roadmap, FAQ, and more
- → Roadmap — Beginner → Expert contribution ideas
Take any circuit and see what it actually does on a real, imperfect quantum
device. Built on top of qcsim (imports it as a library), terminal-only. Where
qcsim gives a perfect Bell state, qnoise evolves it as a density matrix
and applies realistic hardware noise — showing the gap between ideal and real
that quantum error correction exists to close.
Try it now:
git clone https://github.com/LochanPS/Quantum-Collective-Monthly-Projects.git
cd Quantum-Collective-Monthly-Projects/2026-08-noise-simulator/qnoise
pip install -e ../../2026-05-circuit-simulator/qcsim # install qcsim first
pip install -e . && qnoise-runWhat's inside:
| Feature | Description |
|---|---|
| 🎛️ Density-matrix engine | Evolves ρ: ρ→UρU† per gate, ρ→ΣKρK† per noise channel |
| 🌫️ 5 noise channels | Depolarizing, amplitude damping (T1), phase damping (T2), bit-flip, phase-flip |
| 🏭 Hardware presets | ibm_ish, ion_ish, light + custom NoiseModel builder |
| 📉 Readout error | Classical measurement error, per-qubit rates |
| 📊 Ideal vs noisy | Side-by-side ASCII histograms + fidelity / trace distance / TVD |
| 🔬 Noise sweep | Fidelity-vs-rate decay curve, built into the CLI |
| ✅ Parity guarantee | With noise off, reproduces qcsim's exact result — 84 passing tests |
Jump straight to:
- → Challenge description — what to build + minimum requirements
- → Package README — usage, API, quick start
- → Documentation index — architecture, guides
- → Roadmap — Beginner → Expert contribution ideas
- → Add a noise channel — easiest first contribution
| Month | Challenge | Status | Folder |
|---|---|---|---|
| June 2026 | Quantum Circuit Simulator | ✅ Live | 2026-05-circuit-simulator/ |
| July 2026 | Quantum Algorithm Visualizer | ✅ Live | 2026-06-algorithm-visualizer/ |
| August 2026 | Noisy Quantum Simulator | ✅ Live | 2026-08-noise-simulator/ |
We're students, researchers, builders, and professionals learning quantum computing together through hands-on projects, not just theory.
What we do:
- 🛠️ Monthly coding challenges — ship real quantum tools
- 📚 Weekly sessions — Every Sunday, 4:00 PM IST (learning + member showcases)
- 🎤 Expert talks — quantum algorithms, hardware, applications
- 💬 Active community — Discord for code help, WhatsApp for updates
Community values: Inclusive · Collaborative · Hands-on · Supportive · Open
| Week | What happens |
|---|---|
| Week 1 | Challenge released — read the README, ask questions in Discussions |
| Weeks 2–3 | Build in your own fork |
| Week 4 | Post in Discussions, get community feedback |
To submit: Fork → build → post in Submissions
No PRs to main repo needed. See CONTRIBUTING.md for details.
| Need | Where |
|---|---|
| Challenge questions | GitHub Discussions → Q&A |
| Code help | Discord #code-help |
| Submit your solution | GitHub Discussions → Submissions |
| Found a bug | GitHub Issues |
| New here? | docs/FAQ.md |
| Learn quantum basics | Qiskit Textbook (free) |
Top submissions featured on LinkedIn, YouTube, and weekly session showcases.
Apache-2.0 — Build freely, share openly.