Quantum computers aren’t for browsing the Internet, checking email, or running standard software.
Instead, they rely on the underpinnings of quantum mechanics, a branch of physics that’s defied conventional understanding for about 100 years, to manipulate individual particles and solve previously unsolvable problems.
If you wanted to say that a quantum computer runs on magic, you wouldn’t be too far off. Science fiction daydreams like time travel and teleportation are run of the mill when we’re dealing with objects this tiny (think: smaller than an individual atom). The “rules” don’t apply.
This opens up some exciting possibilities, especially in a branch of mathematics known as optimization, which is pretty much what it sounds like: finding the best answer from a large set of potential answers. For such a specific slice of maths, this field addresses some of the most tangible problems in the real world. What’s the best route for a UPS truck to make its deliveries? How do you schedule flights at an airport to keep things running smoothly?
Conventional computers are ill-equipped to handle certain optimization calculations. Professor Daniel Lidar, scientific director at the USC Lockheed-Martin centre for Quantum Computing, says that “it would take many times the age of the universe to try to identify the folded states of a protein, and yet nature can do this in seconds, maybe minutes. It’s had billions of years to think about it.”
In a way, quantum computing taps into nature’s ability to interact with the world. That might be a tough thought to comprehend, but it’s only the tip of the iceberg.
The rules for the microscopic particles that make up atoms are drastically different from the rules for macroscopic objects that we can see with the naked eye.
For example, quantum particles can exist in two places at once, move forwards or backwards in time, and even 'teleport' by way of what physicists call 'quantum tunneling.'
This is the stuff of science fiction to us, but in the quantum world it's business as usual. And scientists can't really explain it.
A widely-known tenet of quantum mechanics (and science in general) is that the simple act of observation changes the outcome of an event. We are limited by the precision of our instruments, and this is especially true of a scientist's inquisitive eyeballs. A quantum particle observed or otherwise measured is a quantum particle changed forever.
Forget the digital bits of ones and zeroes – quantum computers use qubits, and these things are wild.
Quantum computers really, really shine when it comes to solving optimization problems. Some of these problems are so complex that it would require an impractical amount of time for a computer to solve. Like, billions of years.
A classic example is the 'travelling salesman problem.' Imagine a list of towns showing the distances between each one. You're a salesman trying to figure out the shortest route to travel while still visiting every town. The only way to do this with a personal computer is to record the distance of every possible route and then look for the shortest one. This is a very un-sexy approach.
Remember that quantum bits, however, can represent more than one thing simultaneously. This means that a quantum computer can try out an insane number of routes at the same time and return the shortest one to you in seconds, not geological epochs.
No one can really identify the mechanism that lets a qubit represent more than one thing at a time. It's inherent in its weird quantum nature and has thus far defied understanding. But just because we don't understand it doesn't mean it isn't happening.
Scientists have all kinds of ideas as to how it's possible, though. Our favourite is the multiverse theory, an idea in theoretical physics which states that there are multiple (probably an infinite number of) alternative realities.
In this model, a quantum computer solving a travelling salesman-type problem may actually be running calculations in alternate universities, tracing out potential routes in other realities in order to drastically reduce the amount of time required to compute it.
As a quantum computer finds the most optimal way to solve a problem, it relies on some of the basic mathematical tools your own computer uses every day. This generally refers to basic arithmetic, which already pretty optimised.
There's no better way to add a bunch of numbers than to just add them up. There's no better way to multiply numbers than to simply multiply them.
In instances like these, your personal computer is just as effective as a quantum computer.
Outside of being handy at optimization problems, quantum computers will punch holes in our contemporary idea of encryption and data security.
We're talking virtually unbreakable codes for uninhibited communication between anyone.
Zero degrees Kelvin, or absolute zero, is the coldest temperature that can possibly be measured. It's the temperature at which every single atom that constitutes an object stops moving, and therefore stops generating heat.
The inside of D-Wave Systems' quantum computer is kept at a balmy .02 degrees Kelvin. That's about -460 degrees Fahrenheit.
Professor Catherine McGeoch at Amherst University is likely the first person to do a sort of speed comparison between quantum and conventional computers.
Solving the same problem on each computer, she determined that the quantum approach is 'thousands of times' faster.
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