Qubit Simulator

A simple yet flexible statevector-based quantum circuit simulator for Python. It supports common single-, two-, and three-qubit gates (including parameterized gates), measurement (shot-based sampling), state resetting, and basic circuit visualization.

Features

• Statevector Simulation: Maintains a complex-valued statevector of size ( 2^n ).
• Common Gates: X, Y, Z, H, S, T, plus multi-qubit gates like CNOT, SWAP, Toffoli, Fredkin, etc.
• Parameterized Gates: General single-qubit rotation ( U(θ, φ, λ) ).
• Controlled Gates: Automatically construct controlled versions of single-qubit gates.
• Circuit Visualization: Generate a diagram of applied operations with .draw().
• Measurement: Returns shot-based measurement outcomes from the final state.
• Lightweight: Only requires NumPy. For plotting, install optional matplotlib.

Installation

Install Qubit Simulator via pip:

pip install qubit-simulator[visualization]

Usage

Initializing the Simulator

Create a simulator with a specified number of qubits:

from qubit_simulator import QubitSimulator

sim = QubitSimulator(num_qubits=2)

Applying Gates

Apply various quantum gates to the qubits:

sim.h(0)      # Hadamard gate
sim.t(0)      # π/8 gate
sim.cx(0, 1)  # Controlled-Not gate

Custom Gates

Define and apply custom gates using angles:

sim.u(1.2, 3.4, 5.6, 1)  # Arbitrary single-qubit gate

Circuit Drawing

Get a drawing of the circuit:

sim.draw()

Measurements

Measure the state of the qubits:

print(sim.run(shots=100))

{'000': 49, '001': 1, '100': 1, '101': 49}

Statevector Plot

Show the amplitude and phase of all quantum states:

sim.state()

Testing

Tests are included in the package to verify its functionality and provide more advanced examples:

python3 -m pytest tests/

License

This project is licensed under the MIT License.