I’m building a research-grade quantum simulator in Python and need a robust codebase that can accurately model multi-qubit circuits, apply standard gate operations, and return state-vector or density-matrix outputs. Whether you prefer to work directly with NumPy/SciPy or leverage existing open-source frameworks such as Qiskit, Cirq, or QuTiP is completely up to you; the key requirement is clean, well-documented code that runs reliably under Python 3.11. Please provide: • A modular simulation engine capable of handling at least 10-15 qubits, with optional noise or decoherence modelling • A clear, Pythonic API for defining circuits, executing simulations, and extracting results (probabilities, expectation values, etc.) • Unit tests plus a concise README that covers setup, usage examples, and any external dependencies Acceptance criteria: the package installs with pip, passes the included tests, and reproduces benchmark results I will share to within 10 % accuracy. Source files, tests, and documentation should be delivered through a version-controlled repository so I can track progress and run automated checks.