photon-catalysis

Code for "Photon catalysis for general multimode multi-photon quantum state preparation"
Andrei Aralov, Émilie Gillet, Viet Nguyen, Andrea Cosentino, Mattia Walschaers, and Massimo Frigerio
arXiv:2507.19397

---

Installation

Simply run this line to install the package using PIP

pip install -e git+https://github.com/EQ15T/photon-catalysis.git#egg=photon_catalysis

Usage Example

Using this software, one could obtain the set of linear forms in annihilation operator, such that their product, upon conditioning, corresponds to the desired core state. For exmaple, for the state

$$\ket{\psi} \propto \ket{2000} + \ket{0200} + \ket{0020} + \ket{0002}$$

the following code could be used:

from photon_catalysis.utils import kets_to_state_dict
from photon_catalysis.optimal_preparation import optimal_preparation

extra_photons = 2
state = kets_to_state_dict([(2, 0, 0, 0), (0, 2, 0, 0), (0, 0, 2, 0), (0, 0, 0, 2)])
for W, prob, fid in optimal_preparation(state, extra_photons, num_decompositions=10):
    print(W)

Rows of W define the linear forms, extra_photons is the number of catalysis photons. test_photon_catalysis contains tests that could serve as more complete usage examples.