# What is Quantum Computing?

A quantum computer chip that contains four "quantum bits" that can perform calculations.
CREDIT: Erick Lucero |

Quantum computers use the laws of quantum mechanics — in which things can seemingly exist in two places at once or spin in opposite directions at the same time — to put together information. In theory, such computers could perform faster and more complex computations using a fraction of the energy. However, in practice, building a quantum computer is an engineering challenge.

A regular computer processes data in the form of 0s and 1s, binary digits known as bits that are expressed by flicking switch-like transistors on or off. Quantum computers dig deeper and use quantum bits, or qubits (pronounced "cue-bits"). Qubits can be on or off at the same time, a state known as "superposition."

In quantum physics, it is impossible to precisely determine the speed and location of a particle at any given moment. Instead, particles are characterized by a wave function that represents a probability that the particle will be in a given physical state. Instead of 0s and 1s, information is encoded in that wave function and the infinite variations that are possible in the spectrum of the wave.

Let's break it down a little more simply. A regular computer represents data as either a 0 or a 1. There can only be four states: 00, 01, 10 or 11. But in quantum computing, a qubit can represent 1 and 0 at the same time. By increasing the possible combinations of said qubits, you're able to store a larger amount of information than you would by using regular bits.

By doing this, a computer can process data much faster. In fact, at one point, what could have taken years to process and complete could be done in mere seconds with the right set-up of qubits. This is due to the unlimited power of calculations, as a quantum computer can simply perform them faster – much, *much *faster.

The thing is, researchers for years have been investigating various ways of designing a practical implementation of a qubit. So far, none are near completion. The closest researchers have come is envisioning what a quantum computer might look like. Some researchers are focusing on one aspect of quantum computing that can be used to protect information on the Internet, such as credit card information or passwords. Quantum key distribution shows signs of progress.