Tech of the Future: Quantum Computing

By Estefania Barron

Last January, during the 2019 Consumer Electronic Show in Las Vegas, IBM presented its Q System One computer, or what IBM Research called “the world’s first integrated universal approximate quantum computing system designed for scientific and commercial use.”

Sitting elegant in 9-feet-tall, 9-feet-wide glass case, the computer is, according to IBM Research director Arvind Krishna,  “critical in expanding quantum computing beyond the walls of the research lab…”

Although IBM is one of the leading companies in the race to build a quantum computer, it’s not the only one. The list includes other high-profile tech companies.

Quantum computers, being on the cutting edge of recent technology, are still an invention surrounded by fog for most. Thankfully Brooklyn College professor, and author of “Quantum Computing for Computer Scientists” and “The Outer Limits of Reason,” Noson Yanofsky, was able to give me a peek behind the curtains.

“Quantum computing is trying to use the strange aspects of quantum mechanics to make computers better,” Yanofsky said.

Let’s start by thinking of binary digits, the smallest unit of information within a computer. A binary digit, also called a bit, can be either 0 or 1. In the most basic sense, bits are how computers handle data.

Quantum computers, however, have a different way of storing information. Instead of just 1’s and 0’s, information is stored in units that are in superposition, more than one state at the same time. These units are called qubits.

   Say we have an array of numbers stored in a computer, and we are looking for a specific number in that array.  In order to do this, my computer would have to check the first element of the array, then the second element, and so forth until we either find the number or get to the end of the array.

“But if it’s a quantum computer,” Yanofsky said,  “I can split up into all different states at one time and I’m going to look at each one of those things simultaneously.” (see image above).

Quantum computers will be much faster than traditional computers and will bring with them changes to many industries. One of the most significant impacts is believed to be in cybersecurity.

“All Internet security is based on cryptography,” explains Yanofsky.

“I take one number and I take another number and I ask you to multiply them. If you’re in fifth grade, you know how to multiply. But let’s say I give you a big number, and I say, you know what? This big number is a product of two prime numbers. Tell me what the prime numbers are. Well that’s a very hard problem to solve and no computer can do it in a short amount of time.”

This is known as the factoring problem, and most of cybersecurity is based on it.

“Let’s say I’m trying to communicate with Amazon. So Amazon takes two big numbers – and I mean like 120 digit numbers – multiplies them together, [and] sends them to me. I send them my credit card number somehow mingled with that big number, and send it back to them. Because they know where the big number came from, they’re able to figure out my credit card number,” Yanofsky said.

Quantum computers might change this.

In 1994, MIT Applied Mathematics professor Peter Shor found an algorithm that would  factor a given number much more efficiently than a classical computer.

Yanofsky explained this is one of the ways in which quantum computers will change our lives. They will destroy the current cryptography system.

“However, people are already talking about what is called post quantum cryptography,” said Yanofsky. “In other words, whatever system you can break, I can make a harder system that you won’t be able to break. So in that sense, your social security number is safe.”

Putting aside the impact quantum computers will have, there are many challenges in building one; mainly those derived from quantum mechanics. Superposition is a very delicate state that doesn’t like to be interfered with. Once observed, it disappears, turning into a single value; we say the superposition collapses.

“You can’t have things look at it. You can’t measure it. It has to be closed from the world which measures things. Because when you measure things,” Yanofsky said, “The superposition collapses. And then it’s not interesting. It’s just the classical world.”

Because of these limitations, Yanofsky has reservations about the future of quantum computers. Researchers might be able to find their way around the problem, he said, but probably not anytime soon.

        Although it’s exciting to think of the potential of quantum computers, they are not all-powerful machines.

   Let’s take, for example, the Traveling Salesman Problem, a problem used in computer science. The problem asks the following: there’s a salesman that is looking for the shortest path to travel to different cities and sell his product, visiting each city exactly once and returning to the starting point.

So if you have six cities,  you would have to check the total distances of 6! paths (6 x 5 x 4 x 3 x 2 x 1), 720 in total. This sounds simple, but it becomes more difficult when the salesman wants to go to 100 cities, in which case we would check 100! (100 x 99 x 98 x 97….x 1) paths. Let’s assume we have a computer that can check 1 million paths in a second. It would take this computer 2.9 x 10¹⁴² centuries to check all paths. The salesman probably wouldn’t live long enough to get a solution to his problem. We can get a computer that’s 10,000 faster and it would still take it 2.9 x 10¹³⁷ centuries.

    A quantum computer, on the other hand, would be able to find a solution much, much faster – in only 10⁷¹ centuries. Still, not soon enough for the salesman to get the solution to his problem.

“So yes, quantum computers will change our lives, just slowly,” Yanofsky said, “But they will change the world just like modern computers have changed the world.”