Quantum Speed Limit May Put Brakes on Quantum Computers
Sebastian Deffner, 13 Jan 18

How fast can quantum computing get? Research shows there’s a limit. Vladvm/Shutterstock.com

Over the past five decades, standard computer processors have gotten increasingly faster.

In recent years, however, the limits to that technology have become clear: Chip components can only get so small, and be packed only so closely together, before they overlap or short-circuit. If companies are to continue building ever-faster computers, something will need to change.

One key hope for the future of increasingly fast computing is my own field, quantum physics. Quantum computers are expected to be much faster than anything the information age has developed so far. But my recent research has revealed that quantum computers will have limits of their own – and has suggested ways to figure out what those limits are.

The limits of understanding

To physicists, we humans live in what is called the “classical” world. Most people just call it “the world,” and have come to understand physics intuitively: Throwing a ball sends it up and then back down in a predictable arc, for instance.

Even in more complex situations, people tend to have an unconscious understanding of how things work. Most people largely grasp that a car works by burning gasoline in an internal combustion engine (or extracting stored electricity from a battery), to produce energy that is transferred through gears and axles to turn tires, which push against the road to move the car forward.

Under the laws of classical physics, there are theoretical limits to these processes. But they are unrealistically high: For instance, we know that a car can never go faster than the speed of light. And no matter how much fuel is on the planet, or how much roadway or how strong the construction methods, no car will get close to going even 10 percent of the speed of light.

Explaining special relativity.

People never really encounter the actual physical limits of the world, but they exist, and with proper research, physicists can identify them. Until recently, though, scholars only had a rather vague idea that quantum physics had limits too, but didn’t know how to figure out how they might apply in the real world.

Heisenberg’s uncertainty

Physicists trace the history of quantum theory back to 1927, when German physicist Werner Heisenberg showed that the classical methods did not work for very small objects, those roughly the size of individual atoms. When someone throws a ball, for instance, it’s easy to determine exactly where the ball is, and how fast it’s moving.

A radar gun can track a baseball as it moves from the pitcher’s hand to home plate. AP Photo/Charlie Riedel

But as Heisenberg showed, that’s not true for atoms and subatomic particles. Instead, an observer can see either where it is or how fast it’s moving – but not both at the exact same time. This is an uncomfortable realization: Even from the moment Heisenberg explained his idea, Albert Einstein (among others) was uneasy with it.

It is important to realize that this “quantum uncertainty” is not a shortcoming of measurement equipment or engineering, but rather how our brains work. We have evolved to be so used to how the “classical world” works that the actual physical mechanisms of the “quantum world” are simply beyond our ability to fully grasp.

Sign in to view full article

Does Playing Chess Make You Smarter? A Look at The Evidence
The stereotype of the chess player is someone who is smart, logical and good at maths. This is why so ...
Giovanni Sala, Fernand Gobet
Wed, 17 May 17
Karl Marx, the Racist
It’s been nearly 100 years since Karl Marx’s ideas triggered the world’s first communist revolution in Russia on March 8, ...
Jack Phillips
Sat, 11 Feb 17
‘Sip’ Info From Your Smartwatch, ‘Whoosh’ It To Your Phone
With their small screens and our bulky fingers, smartwatches aren’t the easiest devices to control. Researchers have invented new ways ...
Jason Maderer
Fri, 3 Feb 17
Is Violent Political Protest Ever Justified?
The mass protests against Donald Trump’s election, inauguration, and executive actions might subside – but based on the scale and ...
Christopher J. Finlay
Thu, 30 Mar 17
Robots, Aliens, Corporate Drones – Who Will be The Citizens of the Future?
In the 1940s, science fiction author Olaf Stapledon gave a talk to a school about the future. Addressing his audience ...
Will Slocombe
Wed, 22 Mar 17
An Epoch Times Survey
Get your January/February 2018 issue at Kinokuniya stores today!
Sports Elements
Sports Elements
Read about Forced Organ Harvesting
Sports Elements