pennylane-maestro

A PennyLane plugin for the Maestro quantum simulator by Qoro Quantum.

Drop-in replacement for default.qubit — one line change, same code, faster results.

# Before
dev = qp.device("default.qubit", wires=20)

# After 
dev = qp.device("maestro.qubit", wires=20)

Why Maestro?

• Iterate Faster — Up to 20× faster statevector simulations for VQE/QAOA loops.
• Scale Up — Simulate 1000+ qubits using Maestro's optimized MPS backend.
• Sample from MPS — The only PennyLane MPS backend that supports shot-based sampling.
• GPU Ready — Fast GPU simulation on MPS workloads via cuQuantum.

Installation

pip install pennylane-maestro

That's it. This installs pennylane (≥0.38) and qoro-maestro (≥0.3.7) automatically.

Quick Start

import pennylane as qp
import numpy as np

dev = qp.device("maestro.qubit", wires=2)

@qp.qnode(dev)
def circuit(theta):
    qp.RX(theta, wires=0)
    qp.CNOT(wires=[0, 1])
    return qp.expval(qp.PauliZ(1))

print(circuit(np.pi / 4))

Performance

Benchmarked on PennyLane 0.44.1. Run examples/benchmark_lightning_vs_maestro.py to reproduce.

Statevector

MPS — Scaling to 1000+ Qubits

MPS Shot Sampling

🔥 Only Maestro supports this. Neither default.tensor nor Qiskit Aer MPS offer shot-based sampling through PennyLane.

Backends

All backends are selected via keyword arguments — no code changes needed:

# CPU Statevector (default)
dev = qp.device("maestro.qubit", wires=20)

# MPS for 100+ qubits
dev = qp.device("maestro.qubit", wires=100,
                simulation_type="MatrixProductState",
                max_bond_dimension=256)

# Stabilizer for Clifford circuits
dev = qp.device("maestro.qubit", wires=1000,
                simulation_type="Stabilizer")

# Finite shots
dev = qp.device("maestro.qubit", wires=10, shots=10_000)

# GPU (requires separate license — see below)
dev = qp.device("maestro.qubit", wires=28, simulator_type="Gpu")

Device options

Further keyword arguments map onto Maestro's SimulatorConfig:

# Double precision on GPU / Qiskit Aer
dev = qp.device("maestro.qubit", wires=28, simulator_type="Gpu",
                precision="double")

# Pauli propagation with truncation
dev = qp.device("maestro.qubit", wires=200,
                simulation_type="PauliPropagator",
                pp_max_pauli_weight=8, pp_gates_between_trims=10)

# Force gate fusion on; turn off pre-execution reductions
dev = qp.device("maestro.qubit", wires=20, gate_fusion=True,
                enable_causal_cone_reduction=False, auto_reduce=False)

use_double_precision=True/False is still accepted as shorthand for precision="double"/"single". The legacy names pp_pauli_weight_threshold (→ pp_max_pauli_weight) and pp_steps_between_trims (→ pp_gates_between_trims) still work but emit a DeprecationWarning.

Examples

Hamiltonian VQE

Hamiltonians are evaluated natively via Maestro's batched estimate() — all Pauli terms in a single C++ call:

import pennylane as qp
import numpy as np

n_qubits = 20
H = qp.Hamiltonian(
    [0.5] * (n_qubits - 1) + [0.3] * n_qubits,
    [qp.PauliZ(i) @ qp.PauliZ(i+1) for i in range(n_qubits - 1)] +
    [qp.PauliX(i) for i in range(n_qubits)]
)

dev = qp.device("maestro.qubit", wires=n_qubits)

@qp.qnode(dev, diff_method="parameter-shift")
def vqe_circuit(params):
    for i in range(n_qubits):
        qp.RY(params[i], wires=i)
    for i in range(n_qubits - 1):
        qp.CNOT(wires=[i, i + 1])
    return qp.expval(H)

params = np.random.random(n_qubits)
energy = vqe_circuit(params)
gradient = qp.grad(vqe_circuit)(params)

100-Qubit Ising Quench with MPS Shot Sampling

See examples/ising_phase_transition.py for a full demo that simulates a 100-qubit transverse-field Ising model and uses Maestro's exclusive MPS shot sampling to extract magnetization distributions and spatial correlations. Runs in ~30 seconds.

Supported Operations

PennyLane automatically decomposes any unsupported gate (e.g. Rot) into Maestro's native gate set. No manual intervention needed.

🚀 GPU Acceleration

For large-scale workloads, Maestro supports CUDA-accelerated simulation (statevector, MPS, tensor network) via NVIDIA cuQuantum.

dev = qp.device("maestro.qubit", wires=28, simulator_type="Gpu")

GPU Benchmark — Fermi-Hubbard MPS (48 qubits, χ=256)

Larger instances failed to run on some platforms, limiting comparison.

→ Request GPU access & free trial at maestro.qoroquantum.net

Citation

If you use pennylane-maestro in your research, please cite:

@misc{pennylane_maestro,
  author       = {{Qoro Quantum}},
  title        = {PennyLane-Maestro: High-Performance C++ Backend for PennyLane},
  year         = {2026},
  publisher    = {GitHub},
  howpublished = {\url{https://github.com/QoroQuantum/pennylane-maestro}}
}

Authors & License

Maintained by Qoro Quantum (team@qoroquantum.de).

Licensed under GPL-3.0. See the LICENSE file for details.