You may have heard of them, but it’s safe to say you don’t understand how they work. No one does, and they don’t exist yet except in extremely basic forms. If you’re wondering what they will be, or at least what scientists hope they will be, and why, here’s a little overview on the concept.
The further engineers get in creating powerful computers, the more uses emerge for incredible processing power and speeds. The human race’s ability to explore space, cure disease, and solve the larger questions of the universe seems to be pretty contingent on their ability to use computers to collect and process data.
This isn’t a horrible predicament to be in; Gordon Moore was mostly right when he predicted that the number of transistors that engineers can fit onto a computer’s microprocessor would double every two years or so. In fact, it’s been doubling every 18 months for decades.
So where does that leave us in 2020 or 2030? If Moore’s Law holds up, scientists should be able to create a quantum computer within the next decade.
But what is a quantum computer? A quantum computer is a computer that harnesses atoms and molecules to perform processing tasks and read and write memory. Currently these tasks are performed by microscopic silicon-based transistors, but these have their own drawbacks in size and efficiency that scientists hope to improve on by using even smaller particles for the job.
The concept originated when Argonne National Laboratory physicist Paul Benioff applied quantum theory to computers in 1981. He believed that it would be possible to create a quantum Turing machine.
A Turing machine, which was invented by Alan Turing in the 1930’s, is a theoretical device that consists of a tape of unlimited length that has been categorized into little squares. These squares can either hold a 1, a 0, or be left blank. A read-write device then reads these symbols and blanks, which gives the machine its instructions to perform a certain program.
You may recognize this process as a warped version of the one responsible for storing data and running programs on your personal computer or mobile device.
According to Benioff, in a quantum Turing machine, the tape exists in a quantum state, as does the read-write head. Instead of only reading and writing the 0, 1, or space state, quantum computers would encode information as quantum bits (called qubits) which can exist in superposition. A qubit could be an atom, an ion, a photon or an electron and their respective control devices that allow them to work as computer memory and as a processor. Because a quantum computer would be able to work with these multiple states simultaneously, it would have the potential to be millions of times more powerful than the best of the best of today’s computers. The superposition of its qubits would allow for it to work millions of computations while your laptop works one.
Quantum computers would also utilize an aspect of quantum mechanics known as entanglement. Recall that simply giving attention to subatomic particles can change them. That means simply looking at a qubit in superposition could knock it down to a value of either 0 or 1, making it on the same level as your laptop computer. Luckily, the principal of entanglement implies that the application of an outside force to two atoms can cause them to become entangled so that the second atom can take on the properties of the first atom. If left alone, an atom will spin in all directions, but if another atom is added to the company, the entangled atom will spin the opposite direction of the first atom. Scientists can follow this pattern to know the value of the qubits without actually looking at them.