PhotoniQLAB

Introduction

PhotoniQLAB is a Python framework for simulating photonic quantum information processing (PQIP) experiments by an algebraic approach.

As we know, the scale and complexity of PQIP experiments grow rapidly. The time-consuming and error-prone analyzing process for these complex experiments keeps annoying researchers. Typically hours of time and cooperator’s rechecking is needed to verify the correctness of an analysis.

Here comes PhotoniQLAB, a systematic software solution for the pain point.

We have also achieved more appealing goals in PhotoniQLAB beyond its basic duty:

• 🔧 Virtual photonic-lab-style user experience. You can specify a experiment in the similar way of building up the experimental setup in a real lab.
• ♾️ Universality. More than 60 existing PQIP experiments involving multiple encoded degree of freedoms covering various subareas have been simulated by PhotoniQLAB.
• ⚡️ Being efficient enough for most near-term use cases. Because PhotoniQLAB’s creative operators manipulation system is strong but light-weight.

For more details of this project, please refer to our paper:

Wu, Z., Wu, J. & Huang, A. PhotoniQLAB: a framework for simulating photonic quantum information processing experiments. Quantum Science and Technology. 6, 024001 (2021)

Directory structure

- photoniqlab
 - experiments.......Usage cases covering various fields
 - performance.......Code for performance tests
 - photoniqlab.......Source code of PhotoniQLAB
 - test..............Code for unit tests

Installation

You can install our package by the following command under a Python 3.6 environment.

pip install -e .

Usage

To get started with PhotoniQLAB to simulate a PQIP experiment, you need to create a Python script, e.g. yourscript.py, and describe the target PQIP experiment according to the step-by-step tutorial in PhotoniQLAB paper shown in the section of citation.

You can run the Python script to perform the simulation by the following command.

python yourscript.py

After the simulation process finished, you can get some output pdf files containing the simulation results. The content of each file is described by the following table.

File name	Description
init_state.pdf	The initial state of the network
after_layerX.pdf	The quantum state after X layers
post_selected.pdf	The quantum state after post selection
experiment.pdf	The schematic diagram of the network

Simulate real-life examples

Hong-Ou-Mandel dip experiment

The experiment setup of Hong-Ou-Mandel dip experiment (see https://doi.org/10.48550/arXiv.1711.00080) is shown as follows.

The PhotoniQLAB code for simulate this experiment is shown as follows.

# -*- coding: utf-8 -*-

from photoniqlab.sympy_widget import *
from photoniqlab import Experiment, Photons, Detectors, BD, BS, HWP, PBS, POL, PS, QWP

expt = Experiment()

p1 = Photons(1, ['path'], co('p1'))
p2 = Photons(1, ['path'], co('p1'))

bs = BS()

expt.add_sources(p1, p2)
expt.add_elements(bs)

p1.o[0] = bs.i[0]
p2.o[0] = bs.i[1]

expt.build()
expt.simulate()

PhotoniQLAB draws a schematic diagram of the experiment setup to help you debug your description.

PhotoniQLAB outputs the final quantum state of this experiment into a PDF file by the representation of creative operators.

From the result we can verify that the cases of outputting two photons at two sides simultaneously have been cancelled out.

Quantum Bernoulli factory PQIP experiment

The experiment setup of the quantum Bernoulli factory (multiplication operation) PQIP implementation (see https://doi.org/10.1088/2058-9565/ac2061) is shown as follows.

The PhotoniQLAB code for simulate this experiment is shown as follows.

# -*- coding: utf-8 -*-

from photoniqlab.sympy_widget import *
from photoniqlab import Experiment, Photons, Detectors, BD, BS, HWP, PBS, POL, PS, QWP

expt = Experiment()

p = Photons(2, ['path', 'pol'], (1 / sqrt(2)) * co('p1', 'H') * co('p2', 'H') + (1 / sqrt(2)) * co('p1', 'V') * co('p2', 'V'))

pbs_1 = PBS()
pbs_2 = PBS()
bs_1 = BS()
bs_2 = BS()

hwp_1t = HWP(pi/4)
qwp_1t = QWP(0)
pol_1t = POL(0)

# h2 == 0
hwp_1r = HWP(pi/2)
qwp_1r = QWP(pi/2)
pol_1r = POL(pi/2)

hwp_2t = HWP(pi/4)
qwp_2t = QWP(0)

# h2 == 0
hwp_2r = HWP(pi/2)
qwp_2r = QWP(pi/2)
X = HWP(pi/4)  # B is X while A == C == I

pol_H = POL(0)
det = Detectors(2)

expt.add_sources(p)
expt.add_elements(pbs_1, pbs_2, bs_1, bs_2, hwp_1t, qwp_1t, pol_1t, hwp_1r, qwp_1r, pol_1r, hwp_2t, qwp_2t, hwp_2r, qwp_2r, X, pol_H)
expt.add_detectors(det)

p.o[0] = pbs_1.i[0]

pbs_1.o[0] = hwp_1r.i[0]
hwp_1r.o[0] = qwp_1r.i[0]
qwp_1r.o[0] = pol_1r.i[0]

pbs_1.o[1] = hwp_1t.i[0]
hwp_1t.o[0] = qwp_1t.i[0]
qwp_1t.o[0] = pol_1t.i[0]

pol_1r.o[0] = bs_1.i[0]
pol_1t.o[0] = bs_1.i[1]

bs_1.o[0] = det.i[0]

p.o[1] = pbs_2.i[0]

pbs_2.o[0] = hwp_2r.i[0]
hwp_2r.o[0] = qwp_2r.i[0]
qwp_2r.o[0] = X.i[0]
X.o[0] = bs_2.i[0]

pbs_2.o[1] = hwp_2t.i[0]
hwp_2t.o[0] = qwp_2t.i[0]
qwp_2t.o[0] = bs_2.i[1]

bs_2.o[0] = pol_H.i[0]
pol_H.o[0] = det.i[1]

expt.build()
expt.simulate()

PhotoniQLAB draws a schematic diagram of the experiment setup to help you debug your description.

PhotoniQLAB outputs the final quantum state of this experiment into a PDF file by the representation of creative operators, from which we can verify $\ket{h_1, 0}$ has been turned into $\ket{h_1 \cdot 0}$.

Citation

If PhotoniQLAB helps you in your research, please cite our paper :)

__special_katext_id_0__

About

PhotoniQLAB is maintained by the QUANTA lab.

The main maintainers are:

• Prof. Junjie Wu junjiewu@nudt.edu.cn junjiewu@quanta.org.cn
• Zhihao Wu zhihaowu@quanta.org.cn

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This project is under apache 2.0 license. PhotoniQLAB is free to use under the conditions specified in the license.