In this repository, we will collaborate on building a quantum internet and developing applications for it. The repository is divided into five main sections, each concerned with one of the five --- they might increase or decrease later --- layers of the quantum internet stack.

If you're unfamiliar with the internet stack, this blog post by Axel, a PhD student at QuTech, is a great place to begin. To sum up the blog post, the components of the quantum internet are projected to fall into one of five categories or layers.

• The Applications Layer

  The stuff we are actually building the internet to be able to do: quantum key distribution, quantum anonymous voting, etc.

• The Transport Layer

  A set of protocols that together make sure qubits are reliably transmitted between two end nodes.

• The Network Layer

  A set of protocols that together make sure that nodes far away from each other remain connected (entangled) when needed.

• The Link Layer

  A set of protocols that together make sure that nodes close to each other remain connected (entangled) when needed.

• The Physical layer

  The hardware of the internet: optical fiber cables, quantum processors, quantum memories, etc.

Our approach will be to begin from the applications layer: what do we need a quantum internet for? Knowing the answer to this question will help us have a clear idea of the requirements that the other layers must satisfy. We will begin with a specific application (see next section), and while trying to design a quantum internet on which to run this application we will find/create solutions for the problems we will face. Example of a problem that we will need to find solution to: how are we going to send qubits over large distances if we will always have losses in the optical fibers --- or whatever other medium --- through which we are sending the qubits?

As a starting point, we will consider our application to be quantum key distribution using the BB84 protocol (see more in the applications layer folder). Precise initial goal: design a quantum internet that we can use to implement the BB84 protocol fast enough to share 64-bits of secret key in under an hour. This goal might be altered later if it turns out to be too complicated for an initial goal.

Simple: create a fork of the repository, edit the files in the fork, then create a pull request.

If you have a question, you may ask it in the form of an issue. To raise an issue, simply go to the issues tab and create a new issue. Try to create an issue only when necessary (see point 1 in the guidelines below!).

If you don't know how to begin contributing, have a look at the open issues and try to help with one of them. In fact, we recommend you start by doing that.

Open source projects with collaboration on the wide-scale we are going for here can become very messy. Surprisingly, they often don't! Good guidlines help maintain order. The following are a few such guidelines (feel free to propose more guidelines):

1- Help us avoid a mess.

• a) Be polite and thoughtful of others: Let you aim be to understand the other's person point of view, then to learn from them if they are right or to teach them if they are wrong.

• b) Write clearly and precisely, and add figures and videos where possible: helping others understand what's going on quickly helps us all make progress faster.

• c) Avoid redundancy: avoid adding stuff that has been added before, or working on the same thing that someone else is already working on --- help them instead of starting from scratch.

2- Do good science.

• a) Provide evidence.

• b) Be unusually honest about your work; lean over backwards to convey the truth, as Feynman would say.

3- Have fun!