JAQSI

Just another quantum simulator.

📜 About

JAQSI is a gate- and pulse-level quantum circuit simulator built on JAX.
Circuits are plain Python functions that record operations onto a tape; the Script class compiles and executes them, routing between statevector and density-matrix simulation automatically depending on whether noise channels are present. Everything is pure JAX, so circuits are differentiable, jit-able and vmap-able out of the box.

Beyond gate-level simulation, JAQSI simulates circuits at the pulse level by integrating the time-dependent Hamiltonian of each gate, and ships a quantum optimal control module to tune pulse parameters against target unitaries.

🚀 Getting Started

pip install jaqsi

to install our package from PyPI.

import jaqsi

def circuit(theta):
    jaqsi.Gates.RX(theta[0], wires=0)
    jaqsi.Gates.CX(wires=[0, 1])

script = jaqsi.Script(circuit, n_qubits=2)
script.execute(type="expval", obs=[jaqsi.PauliZ(wires=0)], args=(theta,))

You can find details on how to use it and further documentation on the corresponding Github Page.

Looking for quantum Fourier model tooling (ansaetze, expressibility, entangling capability, Fourier analysis) built on top of this simulator? See qml-essentials.

📦 Package Structure

The following diagram provides an overview on how the different components within this package depend on each other. Gates is the entry point for applying gates to a circuit and Script the one for executing it; everything below them is the machinery they dispatch to.

flowchart LR
    jaqsi([JAQSI])
    jaqsi --> jaqsi.gates([Gates])
    jaqsi --> jaqsi.script([Script])
    jaqsi --> jaqsi.qoc([Quantum Optimal Control])
    jaqsi --> jaqsi.math([Math])
    jaqsi --> jaqsi.paulis([Paulis])

    jaqsi.gates --> jaqsi.unitary([UnitaryGates])
    jaqsi.gates --> jaqsi.pulse([PulseGates])
    jaqsi.qoc --> jaqsi.gates

    jaqsi.script --> jaqsi.simulation([Simulation])
    jaqsi.script --> jaqsi.memory([Memory])
    jaqsi.script --> jaqsi.drawing([Drawing])

    jaqsi.pulse --> jaqsi.evolution([Evolution])
    jaqsi.pulse --> jaqsi.envelope([PulseEnvelope])
    jaqsi.pulse --> jaqsi.pparams([PulseParams])

    jaqsi.unitary --> jaqsi.gateset([Gateset])
    jaqsi.unitary --> jaqsi.noise([Noise])
    jaqsi.simulation --> jaqsi.gateset
    jaqsi.simulation --> jaqsi.noise
    jaqsi.paulis --> jaqsi.gateset
    jaqsi.evolution --> jaqsi.ops([Operations])
    jaqsi.math --> jaqsi.ops

    jaqsi.gateset --> jaqsi.ops
    jaqsi.noise --> jaqsi.ops
    jaqsi.ops --> jaqsi.tape([Tape])

    classDef l1 fill:#1f8f5a,stroke:#1f8f5a,color:#d4f7e8
    classDef l2 fill:#2fb170,stroke:#2fb170,color:#d4f7e8
    classDef l3 fill:#58e3a6,stroke:#58e3a6,color:#272a35
    classDef l4 fill:#a8f0d1,stroke:#a8f0d1,color:#272a35

    linkStyle default stroke-width:2px

    class jaqsi l1
    class jaqsi.gates,jaqsi.script,jaqsi.qoc,jaqsi.math,jaqsi.paulis l2
    class jaqsi.unitary,jaqsi.pulse,jaqsi.simulation,jaqsi.memory,jaqsi.drawing l3
    class jaqsi.gateset,jaqsi.noise,jaqsi.ops,jaqsi.tape,jaqsi.evolution,jaqsi.envelope,jaqsi.pparams l4

🚧 Contributing

Contributions are highly welcome! 🤗 Take a look at our Contribution Guidelines.

See our coverage report if you would like to contribute with further tests.