WTF Is Quantum Computing? A 5-Minute Primer

We’ve recently been diving deep on funding to quantum computing startups, working in a nascent industry that saw more than 100% growth in dollar investments last year, as well as notable increases in the number of investors and startups in the space.

But some of our newsletter readers pointed out that it would be helpful to have a primer with a high-level view on quantum computing. If this is you, here we go.

1) What are quantum computers? 

Quantum computers rely on naturally occurring quantum-mechanical phenomena — basically two important states of matter known as superposition and entanglement. These states of matter, when harnessed for computing purposes, can speed up our ability to perform computations on complex sets of data.

The important distinction here is that quantum computers are different from traditional computers, which are binary digital electronic computers that rely on transistors.

Transistors?

Transistors — there’s like billions in your smartphone — get switched from being 0 or 1, on or off, to compute information. Quantum computers do not use transistors (or classical bits), instead they use Qubits.

Qubits are the basic unit of information in a quantum computer.

Qubits can be either a -1 or a 1, or have properties of both of these values, which is called superposition. So, right away there’s a whole lot more possibilities for performing computations.

The most advanced quantum computing technology available today can make use of up to 1,000 Qubits.

Additionally, the Qubit can leverage a state known as quantum entanglement, whereby pairs or groups of quantum particles are linked so that each particle cannot be described independently of the others, even when the particles are separated by a large distance; opposite ends of the universe for example.

Einstein called this “spooky action at a distance” and it’s the theoretical basis for quantum teleportation.

At this point you may be wondering, what’s really in that pipe, Albert?

But don’t worry…

What matters (to those of us who aren’t quantum physicists) is that thanks to Qubits and the phenomena of superposition and entanglement, a quantum computer can process an immense amount of computations simultaneously, and much faster than a classical computer.

2. What are the practical applications of this stuff? 

First, a thought experiment. Imagine a phone book, and then imagine you have a specific number to look up in that phone book. A classical computer that uses transistors will search each line of the phone book, until it finds and returns the match. A quantum computer, because it has Qubits, can search the entire phone book instantaneously, by assessing each line simultaneously and returning the result much faster than a classical computer.

So, apply that to industry problems for which there are a seemingly infinite number of variables and combinations of those variables form a very large set of possible solutions. These massive variable problems are often called optimization problems.

For example, optimizing every airline route, airport schedule, weather data, fuel costs, and passenger information, etc. for everyone in North America, to get the most cost effective solution. Classical computers would take thousands of years to compute the optimum solution to that problem. Quantum computers, theoretically, can do it in a few hours, or less as the number of Qubits per quantum computer goes up, which is already happening …

Steve Jurveston, managing director of the investment firm Draper Fisher Jurvetson, and an early investor in D-Wave Systems, the company widely regarded as a quantum computing pioneer and standard bearer, dubbed the phenomenon of the increasing capacity of quantum computers as “Rose’s Law.” (Geordie Rose, is the CTO of D-Wave, so it’s named after him.)

Rose’s Law for quantum computing parallels Moore’s Law for semiconductor processor development. Basically, quantum computers are already getting really, really fast.

D-Wave is at the forefront of commercial quantum computing applications. But there are some details to take into account. Just listen to Steve Jurveston.

“D-Wave has not built a general-purpose quantum computer. Think of it as an application-specific processor, tuned to perform one task — solving discrete optimization problems. This happens to map to many real world applications, from finance to molecular modeling to machine learning, but it is not going to change our current personal computing tasks. In the near term, assume it will apply to scientific supercomputing tasks and commercial optimization tasks where a heuristic may suffice today, and perhaps it will be lurking in the shadows of an internet giant’s data center improving image recognition and other forms of near-AI magic. In most cases, the quantum computer would be an accelerating coprocessor to a classical compute cluster.”

If you’ve made it this far down the rabbit hole, you’re not alone in thinking, but what about me?

If a D-Wave machine isn’t in the cards, IBM is already offering “the world’s first quantum computing platform delivered via the IBM Cloud,” meant to unleash quantum processing power to the masses, and effectively render the following statement false, yet again.

They are not, and it is not simple.

3. What does cybersecurity have to do with quantum computing?

Modern cryptography (secret codes) relies on a mathematical function called prime number factorization. Basically, large numbers are broken down into prime numbers that can then be multiplied together to get the large number. Classical computers are not good at this and take a long time to crack cryptographic codes based on prime number factors. But, you guessed it, quantum computers are really, really good at it.

Governments all over the world are racing to build quantum computers that can render all modern forms of cryptography obsolete.

In an effort to develop hack-proof communications, the Chinese government recently launched into orbit what is said to be the world’s first quantum satellite. That satellite’s name is Micius. Micius is designed to develop quantum-encrypted communications over long distances.

This is not Micius.

There goes Micius!

Quantum encryption is the idea of sending entangled particles of light (entangled photons) over long distances in what is known as Quantum Key Distribution (QKD) for the purpose of securing sensitive communications.

In QKD, both the sender and recipient measure the polarization of entangled photons they receive, by assigning each photon a 0 or 1. This creates a quantum key, that can be used to decipher an encrypted message.

The most important point is that if the quantum entangled photons are intercepted by anyone, the system will show immediate signs of disruption and reveal that the correspondence is not secure.

Quantum computers rely on the fundamentals of quantum mechanics to speed up the process of solving complex computations. Often those computations incorporate a seemingly unfathomable number of variables, and the applications span industries from advanced genomics to finance. Also, quantum computers are already reinventing aspects of cybersecurity through their ability to break codes based on prime number factorization, as well as their ability to offer advanced forms of encryption for protecting sensitive communications.

Further reading: 

• 6 Charts Breaking Down The Nascent Quantum Computing Startup Ecosystem
• Quantum Computing: 17 Years Of Major Startup Financings In One Timeline
• 18 Corporations Working On Quantum Computing

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