images by Clément Meignant

This repository has be made during the 2019 edition of the Pan-European Quantum Internet Hackathon — Paris Node, on November 5th and 6th, 2019.

It deals with Distributing Graph States Over Arbitrary Quantum Networks using Simulaqron.

The paper can be found at the following URL: https://arxiv.org/pdf/1811.05445.pdf

This project uses Simulaqron, an application level simulator for a quantum internet: https://www.simulaqron.org/

The package needs Simulaqron to work properly PYTHONPATH should be in the Simulaqron directory

git clone https://github.com/francois-marie/StarExpanders
cd StarExpanders
export PYTHONPATH=$(pwd):$PYTHONPATH
python network.py
python network2local.py
./start.sh
./run.sh

network.py generates a json file descriptive of the directional network with specific id and a specific folder for the protocol execution id_network.json Creates the protocol for the execution of the nodes to go from the network to a GHZ of specified nodes id_protocol.json TODO: generate protocol automatically from the network and the list of target nodes

network2local.py Generated two bash scripts

• To start the simulacron network start.sh
• To execute the protocol on the nodes run.sh

start.sh

run.sh calls run_node.py to generate the CQCConnection for each node and execute the protocol for star expansions.

{"alpha": {                 # Node number 1
    "my_name": "alpha",     # Node name
    "target": ["beta"],     # Node number 1 sends one qubit of EPR pair to Nodes in "target" list
    "receivers": 2          # Node number 1 receives one qubit of EPR pair sent by 2 receivers. (port_A) identifies the sender
    },
    ...
    }

Create GHZ state

[
    {
        "place": "gamma",       # Node at which GHZ state preparation takes place. Node isolated in the final GHZ state
        "source": "delta",      # Center node in the final GHZ state
        "targets": ["gamma"]    # Nodes connected in the GHZ state to the center node
    },
    ...
]

locally using CZ gates at each node

and its connections: Measure Z

CZ+Y_Y

Implement local corrections for GHZ star expansion

Generate automatically the protocol to get GHZ from a graph given a list of targets

This example was created at the Pan-European Quantum Internet Hackathon — Paris Node, on November 5th and 6th, 2019.

The team members were:

• Frederic Grosshans
• Shraddha Singh
• Georg Harder
• Sivasothy Shanmugalingam
• Francois-Marie Le Régent

You can play a demo of the final run of the protocol using the following command:

sudo apt-get install ttyrec
sudo apt-get install imagemagick
sudo apt-get install python-opster
ttyplay ttyrecord

Make sure ttyrecord is in your present working directory