Getting started

quantlop is a high-performance quantum simulator for evolving systems whose Hamiltonians can be expressed as sparse sums of Pauli words. It applies those operators directly to the state vector and uses a Krylov method to approximate the matrix-exponential action, avoiding the memory cost of constructing a dense Hamiltonian.

This page walks you through installing quantlop, defining a qubit Hamiltonian in the Pauli basis, preparing an initial state, and running your first matrix-free simulation.

Installation

Create or activate a Python virtual environment, then install the latest release from PyPI:

pip install quantlop

Working on quantlop itself?

Clone the repository and install the package with its development tools:

pip install -e .[dev]

Quick example

Here is a simple code example using quantlop native data structures:

import numpy as np
import quantlop as ql

num_qubits = 3

pwords = [
    ql.PauliWord(coeff=0.5, string="ZZI"),
    ql.PauliWord(coeff=0.2, string="YIX"),
]
ham = ql.Hamiltonian(pwords=pwords)

psi = np.zeros(2**num_qubits, dtype=complex)
psi[0] = 1.0

evolved_psi = ql.evolve(ham, psi)

The interface allows to import Hamiltonians from other quantum computing frameworks using from_pennylane() and from_qiskit().

Multi-threaded execution is also available by passing num_threads to the quantlop.evolve() function.