What is Quantum Computing?
In this day and age, it’s easy to think that the great days of scientific innovation are behind us. We’ve landed on the moon, we’ve created the modern digital computer, we’ve created smartphones. But there are plenty of exciting technologies that are still in their infancy. One of them is the quantum computer.
You might have heard “quantum computer” mentioned here and there, or maybe just the word, “quantum.” What exactly is a quantum computer? How does it work, and what are the applications?
Let’s answer your questions about this exciting new field of research.
It’s all about atoms
What does “quantum” mean? In this case, quantum refers to the world of atoms and subatomic particles. Quantum computing attempts to make calculations that simulate the ways in which subatomic particles interact with one another.
There’s no doubt about it: this is a very complicated field of research and you have to know quite a bit about quantum physics and computer engineering to fully wrap your head around it. But the basics of quantum computing are relatively easy to grasp.
How does the subatomic world work? It all starts with the atom. Atoms are the building blocks of the universe, the smallest known units of matter. The strange thing about atoms is that they don’t seem to obey the same laws that govern physics at the human scale. The subatomic world seems to have its own set of laws by which it abides.
There are two important subatomic laws that you need to know in order to understand quantum computing.
Superposition
Warning: this might blow your mind.
A single atom has the ability to be in two different places at one time.
Breath. Take a moment to let that sink in.
It’s true, though. One atom can be in two places simultaneously, a quality known as “superposition.” This has been observed in many different quantum experiments. Physicists have directed electromagnetic waves at atoms, and have observed superposition in effect.
But, wait! If an atom can be in two places at once, why aren’t human beings in two places at once?
Nobody knows. And another strange thing is that we can’t actually observe the atoms being in the same place at once. We have evidence of atoms being in superposition, but when we observe the particles, we can only ever locate the atom being in one place or the other [1].
Entanglement
Entanglement is another bizarre phenomenon of the subatomic world. Entanglement is when two atoms behave in the exact same way, even when they’re separated by physical space. What happens to one atom will also happen to the other. It’s another strange subatomic interaction that we don’t experience at the human scale. Albert Einstein referred to entanglement as “spooky action at a distance.” [2]
How standard computers work
To understand how a quantum computer works, you first need to understand how a standard binary computer works. The components in your computer exchange electric currents. For instance, when you open a saved file, your CPU sends an electric pulse to your hard disk.
The pulse isn’t constant. It flickers, like Morse code. When the current is running, the hard disk registers a 1. When the current is off, the hard disk registers a 0. This binary value of either a 1 or a 0 is called a “bit.”
Think of a bit as a letter. When you string many letters together, they form a word. In the same way, the series of bits form instructions that tell your hard disk to retrieve the file from storage. Binary is the main language of computer systems.
There’s one problem with binary language: it can only process one series of bits at a time. Computers are fast enough to perform most of the calculations that you’ll use in your daily life. But there are many subatomic calculations that require such a massive amount of numbers, that no standard computer has the size or power to perform them.
Quantum computers
The main goal of a quantum computer is to perform computations by using subatomic principles - namely, superposition and entanglement.
While a standard computer uses bits, a quantum computer uses qubits (pronounced “Q-bits”). A qubit is not binary. A qubit can be a 1, or a 0, or both at the same time. It’s exactly like an atom, capable of being two different things simultaneously. A qubit simulates the superposition of atoms that we observe in the subatomic world.
Qubits are advantageous for two reasons. First, you’re able to compress more information into a single unit of data. Second, qubits make it easier for scientists to make calculations that account for superposition. Qubits also can account for entanglement. On a quantum computer, scientists would be able to enter conditions that allow for qubit entanglement.
A quantum computer looks nothing like the computers that occupy our workplace or home office. They look more along the lines of the first modern computers engineered in the 1940s. They have to be that large if they’re going to perform calculations on a quantum scale.
How can quantum computing benefit us?
Quantum computers can help us create more powerful encryption methods so we can better protect our personal information. Qubits can hold far more information than bits can, and so they’re a better data unit to be used for creating complicated encryption algorithms. Quantum computers could tremendously improve cybersecurity.
Quantum simulation may be the most important benefit of quantum computers. Because they can simulate quantum physics, researchers may be able to perform a greater variety of experiments involving the subatomic world. Chemists may be able to use quantum computers to simulate chemical reactions, which may help them create new medicines [3].
Do quantum computers already exist and can I use one?
Quantum computers do exist, but the technology is in its infancy. Currently, quantum computers have few useful functions because there are still aspects of the technology that have not been developed. Computer engineers and mathematicians are hard at work making advancements in the field so that quantum computers in the future will be as revolutionary as we dream they’ll be. But don’t expect to be bringing one home from the electronics store any time soon.
However, you can play an online game on a quantum computer! Check out this simple quantum computer game. Hopefully, it’ll hold you over until the technology matures.
[1] IBM.com; What is quantum computing?
[2] Quantamagazine.com; Entanglement Made Simple
[3] Bloomberg.com; Why Quantum Computers Will Be Super Awesome, Someday
