SeQUeNCe is an open source, discrete-event simulator for quantum networks. As described in our paper, the simulator includes 5 modules on top of a simulation kernel:

• Hardware
• Entanglement Management
• Resource Management
• Network Management
• Application

These modules can be edited by users to define additional functionality and test protocol schemes, or may be used as-is to test network parameters and topologies.

SeQUeNCe requires an installation of Python 3.8 or later. This can be found at the Python Website. Then, simply download the package, navigate to its directory, and install with

$ pip install .

Or, using the included makefile,

$ make install

This will install the sequence library as well as the package dependencies.

Once SeQUeNCe has been installed as described above, simply run the gui.py script found in the root of the project directory

$ python gui.py

or

$ python3 gui.py

Please cite this work as follows:

• X. Wu, A. Kolar, J. Chung, D. Jin, T. Zhong, R. Kettimuthu and M. Suchara. "SeQUeNCe: A Customizable Discrete-Event Simulator of Quantum Networks." Quantum Science and Technology, 2021. DOI: https://doi.org/10.1088/2058-9565/ac22f6.

• X. Wu, A. Kolar, J. Chung, D. Jin, T. Zhong, R. Kettimuthu and M. Suchara. "SeQUeNCe: Simulator of QUantum Network Communication." GitHub repository, https://github.com/sequence-toolbox/SeQUeNCe, 2021.

Many examples of SeQUeNCe in action can be found in the example folder. These include both quantum key distribution and entanglement distribution examples.

Code for the experiments performed in our paper can be found in the file starlight_experiments.py. This script uses the starlight.json file (also within the example folder) to specify the network topology.

The example folder contains several scripts that can be run with jupyter notebook for easy editing and visualization. These files require that the notebook package be installed:

$ pip install notebook
$ pip install ipywidgets

To run each file, simply run

$ jupyter notebook <filename>

These examples include:

• BB84_eg.ipynb, which uses the BB84 protocol to distribute secure keys between two quantum nodes
• two_node_eg.ipynb, which performs entanglement generation between two adjacent quantum routers
• three_node_eg_ep_es.ipynb, which performs entanglement generation, purification, and swapping for a linear network of three quantum routers

The example directory contains an example json file starlight.json to specify a network topology, and the utils directory contains the script draw_topo.py to visualize json files. To use this script, the Graphviz library must be installed. Installation information can be found on the Graphviz website.

To view a network, simply run the script and specify the relative location of your json file:

$ python utils/draw_topo.py example/starlight.json

This script also supports a flag -m to visualize BSM nodes created by default on quantum links between routers.

This project includes a modified fork of the Quantum++ library version 2.6. Please see the Quantum++ LICENSE file for more information.