There’s a war raging in Silicon Valley right now, and it’s attracting everyone from Google to IBM to Microsoft, along with a flock of ambitious new startups. Despite what you might expect, they’re not fighting over social media, mobile games, or e-commerce; they’re after something downright otherworldly: parallel universes.
Despite sounding like the premise of a Black Mirror episode, this is actually a pretty fair way to describe the current holy grail being sought after by the world’s tech giants. The rapidly-developing field of quantum computing promises to bring changes that are both profound and unnoticeable. For reference, traditional computers use “bits,” which can be either a zero or a one, in order to represent information. By contrast, quantum computers represent information using quantum bits, also known as “qubits.” By taking advantage of quantum mechanics, these qubits can be both zero and one at the same time. One of the field’s pioneers, a British physicist named David Deutsch, described this effect as processing information “in collaboration between parallel universes,” owing to the fact that multiple realities are simultaneously superimposed on the quantum state. Yeah, this stuff gets heady real quick. Basically, by carefully controlling how these realities interfere with each other, phenomena like this can enable computers to solve a whole new set of applications entirely beyond anything a classical computer could do. That said, these machines aren’t going to affect most people’s lives in any overt way. They aren’t built to run Red Dead Redemption 2 any better and they certainly don’t speed up Chrome. What they will do is redefine a few key problems behind the scenes, so if everything goes right, your life will get a little bit better, even though you’ll probably never realize it. Thus, as the quantum revolution draws increasingly imminent, it seems apparent that quantum technologies are poised to be the quietest disruptive technology in decades.
So what can these machines actually do? Surprisingly, despite the billions of dollars being dumped into their research right now, I could count the number of well-defined applications for quantum computers on my left hand. Hell, I can list some right now: break encryption, search databases, model quantum states (shocker), optimize complex systems, and advance machine learning. That’s it — just five things. What’s fascinating to me is that even though the number of applications is low, the impact of solving each of these problems is incredibly high. Even though we’ll surely find other uses for them in the future, these devices already have a solid collection of killer applications. For example, consider the impact of quantum computers on encryption. There’s a particular algorithm called Shor’s Algorithm which can factor large numbers efficiently, whereas this problem quickly becomes infeasible on a classical computer. This might be a simple mathematical curiosity if it weren’t for the fact that the most prevalent form of encryption, RSA, relies on the assumption that factoring large numbers is practically impossible. If someone were to build a computer with a couple thousand qubits, they could decrypt and read virtually all online traffic. That’s banking transactions, private photos, social security numbers, and more. Essentially, any piece of information you wouldn’t tell a stranger could be exposed in seconds. Cases like this demonstrate how, if you follow a couple stages of cause and effect, seemingly innocent applications of quantum computers quickly become all too real.
However, returning to the encryption example, it is important to note that all hope of privacy is not lost. While quantum computers may pose an existential threat to classical cryptography, a related field called quantum communication may offer a powerful remedy. Similar to quantum computing, this technique substitutes quantum states for zeros and ones in order to exploit the strange effects that occur on quantum scales. In particular, quantum communication leverages the fact that quantum states can look different depending on how they are measured. Measuring also changes the quantum state being observed with high probability. Additionally, quantum states are protected by the no-cloning theorem, which holds that unknown quantum states cannot be perfectly duplicated. The combination of these three effects means that if two people are communicating with quantum states, an eavesdropper would be unable to intercept their communications successfully and would expose themselves in the process. In contrast to traditional encryption, this security is not derived from computational complexity. Rather, the communication is impregnable due to the most fundamental laws of physics. Even though quantum technology presents challenges like this in every area it affects, more often than not, it provides a solution which is even stronger than what we had before. I can hardly think of a better criterion for cutting-edge technology than something which solves its own problems. As such, it seems incomprehensible to me to call quantum technologies anything less than revolutionary.
If current trends are any indication of this industry’s future, that revolutionary inflection point is a lot closer than you might think. In my opinion, it won’t be more than a decade before we start to see rudimentary quantum devices come into production. While we really can’t do much with the small scale models we have now, I believe that we’re on the cusp of turning academic curiosities into commercial realities. Rigetti Computing, an emerging player in the field, has made particularly impressive strides in creating chips that utilize superconductivity to build quantum circuits. One key advantage of their approach is that their fabrication processes utilize existing manufacturing techniques that have been used for decades to produce traditional silicon computer chips. However, in this case, they’re adding a few key elements and freezing the whole thing to make quantum states out of a continuously looping electric current. It’s a bit like having a roller coaster that never speeds up and never slows down; it just keeps on going around the track forever without any energy input. The direction of this flow can itself be a quantum superposition, flowing both one way and the other at the same time. I know this is some seriously bizarre shit, but all of that is to say that they’re building quantum chips that would be pretty feasible to mass produce if they can push their research just a bit further. That said, there are certainly a number of challenges in the way of stable quantum computation, including many that you might not expect. Essentially, such issues all revolve around the fact that quantum states are incredibly delicate creatures, yet nature is aggressively unsympathetic.
To a quantum state, the universe is a terrifyingly turbulent place. At an atomic scale, things such as heat, light, and sound are like miniature hurricanes that can cause massive disruptions to these fragile beings. Whether that state is a photon, an ion, an electron, or something else entirely, it can’t take much of a hit before things go horribly wrong. Trying to run a quantum computer at room temperature is like trying to do calculus in the middle of a typhoon; even if you’re attempting to do things in an orderly way, your environment is terribly distracting, to say the least. That’s why a key component of building a functional quantum chip is being able to isolate it from everything else happening in the world. Oftentimes, that means getting it really, really cold. I’m not talking human cold here, I’m talking physics cold. To understand what exactly that means, consider the temperature at which water freezes. Now depending on your temperature scale, that’s either 32 degrees Fahrenheit or 0 degrees Celsius. Either way, you’ll probably want to layer up before going outside. However, by another temperature scale called the Kelvin scale, that’s a scorching 273.15 K. Unlike Fahrenheit or Celsius, Kelvin scale is an absolute temperature scale, which means that the coldest temperature physically possible is 0 K. So how low do quantum computers’ temperatures go? Usually down to about .015 K, a temperature which is far too cold for us to intuitively comprehend. For a point of reference, interstellar space, with no heat source around for many light years, is still about a thousand times hotter than these chips, on average. Achieving these low temperatures is an engineering marvel in and of itself. Add onto that challenge the difficulty of controlling something that breaks when you look at it, and you start to get a sense of why quantum computers are still very much a work in progress.
That said, there are lots of very smart people who have made tangible results in this seemingly impossible sector. The aforementioned Rigetti Computing released a promising 19-qubit chip last year, which dwarfed their previous 8-qubit chip. Google has been working on a very exciting superconducting chip consisting of a whopping 72-qubits. While other companies like Microsoft and IBM may not have the raw numbers to compete with these specs, they still have very promising research going on as well, primarily relating to small quantum devices. As someone who does his best to keep up with the field, I have to say that the sheer number of new techniques being published every week is promising in and of itself.
When you combine the sheer number of attempts with a few outstanding cases of success, it certainly feels like the industry is just waiting for that one key development to make everything else fall into place at the snap of a finger. That key development, by the way, is finding a scalable qubit design. Error and noise can be accounted for with sufficiently powerful error correction methods, and new fabrication techniques will surely be developed if necessary. The key behind it all is being able to put a lot of qubits on the same chip and have them all talk to each other. In other words, scalability. Once that becomes feasible, quantum computers will become a reality overnight, and I mean that literally. The demand for them is just so unbelievably great due to the simple fact that the primary customers seeking out these devices are national governments and multinational corporations. If anyone has the deep pockets necessary to accelerate this technology’s development, it’s these guys, and for good reason. In an increasingly interconnected world, information is everything, and being able to process that information in more powerful ways than your enemy is a key strategic advantage. Whether that enemy is a rival company or a rival state, the principle remains the same.
Agencies like the NSA realize this, and subsequently have invested heavily into the development of quantum computers. China has done the same, and has actually gone further. In an example of rational foresight, they have preempted our research into quantum computers by developing their own quantum communication system to protect high level exchanges in a post-quantum world. They actually launched a satellite a few years ago which uses laser beams to shoot linked quantum states down to base stations, establishing an unbreakable encryption key between two parties. This works because the states are “entangled,” meaning that they will both give the same measurement instantaneously, no matter how far apart they are. By reading a sequence of these photons, parties can establish an invulnerable key and have a truly private conversation that not even the NSA can intercept. Again, by turning to examples like this, we are only scratching the surface of the impacts these machines will have on our modern world! This technology will have countless profound impacts that no single article could hope to explore, yet those impacts are still incredibly real. For example, these wonderful devices will help us rapidly simulate chemical interactions to expedite drug development, totally reshaping the medical sector as a result. Of course, we could turn our quantum powers to the energy sector as well. Armed with a network of sensors, one chip could optimize power grids on a national level, increasing energy efficiency and lowering emissions. Alternatively, if you fed one of these chips a dataset, it could advance scientific research by exposing imperceptible patterns in way that existing computers simply can’t. On top of all that, it might even make your Google searches just a tiny bit better than they already are.
With so many features looming just over the horizon, it’s an undeniably thrilling time to be involved with this branch of technology. The impacts it’ll have are simply colossal, both in terms of breadth and in depth. Despite all of this, however, you’ll still probably never truly realize its full impact on your life. Besides hearing “quantum” used as a buzzword, you’re unlikely to own or even see a quantum computer, in my opinion. This isn’t even necessarily due to technological reasons, but rather to economic ones. A quantum computer just isn’t a consumer product. The kinds of problems they’re built to solve are important, yet boring. Though necessary, such solutions live behind the scenes of our daily technology interactions. Consider this: how many people do you think know what kind of database search algorithms their favorite websites use? Probably not a lot. Why, then, would things be any different in a post-quantum world? The beauty of our information ecosystem is that it is complex enough to do what we want, yet simple enough that the average person can use it to great effect. By allowing a few key individuals to manage that ecosystem, the rest of us can use it to affect society in powerful ways. That being said, every now and then it can be interesting to take a peek behind the curtain and see the digital cogs that power our world. Of course, when we look at quantum technologies, we might be peeking just a little bit into the future as well. And unlike a quantum state, this reality isn’t poised to change whenever we examine it; it’s here to stay for a long time to come.