Bench Talk

(Source: kras99 – stock.adobe.com)

As if the internet couldn’t get any more overwhelming, we have to go and add the word “quantum” in front of it. Why?

To answer this question, I recently sat down with Aharon Brodutch, CEO of Entangled Networks, to find out what the big deal is about the Quantum Internet, or if it’s even a deal to most of the general public at all.

Aharon, so, what even IS the Quantum Internet?

Quantum information is very different from classical information. When we transmit information over the internet, it is encoded in bits. Each bit can be either 0 or 1. Quantum mechanics allows systems to be in a superposition of states. A famous hypothetical experiment called Schrodinger's Cat showed that a quantum cat can be in a superposition of "dead" and "alive". That is, it can be in a state that is neither dead nor alive, something which is inconceivable outside the quantum world. This superposition state is very difficult to maintain. Going back to the cat, although it can be in this strange superposition state, when we try to observe it, we will destroy the superposition and see either a dead or a living cat. Similar to the cat, a quantum bit (qubit) can be in a superposition of 0 and 1, allowing a wide range of interesting applications. But again, like the cat, the superposition is very fragile, and all the quantum properties can be lost abruptly if the system is disturbed.

A quantum network is a network that allows quantum information to be transmitted between quantum nodes. These can be quantum computers, quantum sensors, or quantum cryptography modules. Small quantum networks are important for linking quantum computers and getting them to work together, similar to supercomputers. A quantum internet is a large quantum network that allows multiple users across the world to send quantum information from quantum nodes like quantum computers, quantum sensors, and quantum cryptography modules.

Right, so what I understand is that it’s not for sending cat memes to one another. Even Schrodinger’s Cat memes. Tell me then, what is it useful for?

The most prominent use cases for a quantum internet are centered around data security. The fact that the quantum system can exist in superposition (think of the cat that is neither dead nor alive) but cannot be observed in superposition (when we look at the cat, it is either dead or alive) makes it a great tool for data security. The simplest application in cryptography is distributing a secure key that can be used to encrypt information. A more interesting application is private computation where a user can run a program on a computer in the cloud without anyone else—including the computer—knowing what they are running. This is an incredibly important security paradigm in a world that is increasingly switching to cloud computing. Imagine being able to use Gmail without needing to trust Google to secure your information.

A second use case is sensing. Quantum sensors can be significantly more sensitive than classical sensors. Again, this is due to the ability to maintain a superposition. A quantum internet will allow multiple sensors to work together by having a shared state that can be in a superposition. This would enable unique situations like having a network of sensors across the globe act as if they were a single giant device. And if that were not enough, the security alluded to above would be a free feature that can be used to hide the information collected from unwanted eyes.

So, if you’re a digital sensor or you have major digital trust issues, QI might be for you! How else will it meaningfully change user experience?

This is a very difficult question to answer. Imagine asking what a worldwide network would be used for in the late 60s when ARPANET was being developed. Current use cases (like the ones we just discussed) are focused on power users such as government and large enterprises who need to protect data and use extremely accurate sensors.

From their perspective, the development would be an extension of existing developments in both security and sensing. The one exception is the ability to securely use quantum computers over the cloud. Quantum computers offer game-changing abilities to perform certain computations, but are expected to be expensive to build and maintain. The ability to use them securely but keep them in a centralized location would allow a much wider user base and offer immense computational resources.

Looking further into the future, a quantum internet in every home would allow an extreme level of security and anonymity. Again, imagine using Google without Google knowing who you are or what you are doing. The potential—both positive and negative—is immense.

So, we’ll finally be able to claw some anonymity back from the all-seeing, all-knowing tech behemoths, if we’re savvy enough. But not everyone will be savvy enough, I imagine, so there’ll probably be systems built to leverage it invisibly. Will people actually know if they're using it?

At the moment, anyone using any kind of quantum technology is very aware that they are using this technology. However, the dream from a developer's perspective is to make the user's experience as simple as possible. Usually, you are not aware if someone upgraded the security features on your computer or if your internet provider has upgraded the network. You might notice things are running faster, but you might not even know why. This is even true of the pinnacle of quantum technology, quantum computers. As a user, you might realize that you are able to run some programs that were simply impossible before, but you would not need to know why this is happening. Think as an example of the technologies required to allow streaming Netflix on your phone. Most users are unaware of the nature of the technological breakthrough; they just know that it works and perhaps realize their phone bill has changed.

Ok, but here’s a big one. There’s so much talk about quantum things, and has been for so long, but the reality seems to be hitting all kinds of walls. So, tell us, is the Quantum Internet actually possible?

Yes. There are many challenges associated with a quantum internet, but the underlying concepts are based on fundamental quantum mechanics, our most tested physical theory. If we find a reason that would make the Quantum Internet impossible, it would be the greatest scientific breakthrough of the last 100 years.

Good to know! I’m glad things seem to be progressing. Could you tell us more about who is building the Quantum Internet and how far along are we in that process?

Quantum communication has been studied as an academic discipline for the last 50 years, with a huge boost in the 21st century. However, it was—and still mostly is—in the realm of physicists and theoretical computer scientists. Over the last few years, there has been a shift toward industry, and some thought is being given to engineering. One particular reason this area is not as active (in industry) as quantum computing is that the most important use cases of a quantum internet would require some of the nodes to be quantum computers.

Recent US government initiatives have led to some work in industry, including a few startups that specialize in building quantum networking equipment. This is supplemented by various startups as well as large multinationals that are working on quantum cryptography. Demonstrations of quantum networks over long distances include networks across various cities as well as quantum communication with satellites.

Work on quantum computing—an emerging but fast-growing industry—is important to quantum networking. Most of the existing efforts in building quantum computers will require a networked architecture: many small quantum computers working together over a (local) quantum network. This is very similar to HPCs, which are built of many compute nodes (each node is a computer). While the networks required for quantum computers are different from a quantum internet, the basic building blocks are the same. Most quantum computing companies are either thinking or actively working on quantum networking. Over the last two years, a few quantum networking startups (e.g., Entangled Networks) have focused on the networking aspects of "multi-core" quantum computation. 

I’m so impatient! How far are we from the Quantum Internet being a reality?

A fully fledged (worldwide) quantum internet is still a dream, and it is difficult to predict when all the necessary ingredients will be ready for deployment. However, the need for quantum networking as a part of the intense efforts in building quantum computers is driving this dream closer to reality. This comes together with the very real need to protect data and the relative maturity of point-to-point quantum cryptography. Current industry timelines show a need for networked "multi-core" quantum computers sometime in the middle of this decade (see for example IBM's recent roadmap). These timelines suggest that the necessary components for a quantum internet will be ready before the end of the decade. It is then mostly a question of the maturity of use cases beyond cryptography and the need for quantum cryptography over a quantum internet that will drive industry and/or government in the direction of a quantum internet.