Extending with Surface Codes

Surface codes are the flagship model for scalable fault-tolerant quantum computing. OpenQStack is built to support their simulation, decoding, and visualization.

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Step 1: Create the SurfaceCode Class

Inside openqstack/surface_code/, create a new file surface_code.py:

class SurfaceCode:
    def __init__(self, distance=3):
        self.distance = distance
        self.lattice = self._initialize_lattice()

    def _initialize_lattice(self):
        # Create qubit/stabilizer map here
        pass

    def apply_noise(self, channel):
        # Inject noise to data qubits
        pass

    def extract_syndrome(self):
        # Simulate parity checks
        return syndrome

    def decode(self, syndrome):
        # Placeholder for MWPM or table-based decoder
        pass

    def recover(self, correction_ops):
        # Apply recovery to lattice
        pass

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Step 2: Create Visualization Hooks

Add plotting tools under visualize_surface.py, such as:

• plot_syndrome_grid()
• highlight_logical_path()
• animate_surface_cycle()

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Step 3: Build a Demo

Create examples/surface_blink.py:

from openqstack.surface_code.surface_code import SurfaceCode

code = SurfaceCode(distance=3)
code.apply_noise(channel)
syndrome = code.extract_syndrome()
correction = code.decode(syndrome)
code.recover(correction)

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Step 4: Add Decoders

Create decoder/ module with:

• mwpm.py
• lookup.py
• ml_decoder.py

Each decoder should expose a function:

def decode(syndrome, code_distance):
    return list_of_pauli_corrections

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Contributing Surface Code Modules

We are actively developing the surface code framework.
If you're interested in helping with:

• Syndrome logic
• Visualizations
• Benchmarking tools
• Advanced decoding

Open an issue or join our discussions.