What is Quantum Computing for?

In 2019 a team from the University of California beat out the world’s largest supercomputer with a quantum computer. It was able to solve a complex task in 200 seconds (a conventional supercomputer would have taken 10,000 years to do the same).

Quantum Computing, bits and qubits?

Our daily lives are becoming more and more computerized. This means that more and more binary codes (what we commonly call bits) are generated and represented by “o” or “1”. However, if we talk about quantum physics, this gets complicated: there are qubits and quantum bits. Moreover, they can represent both 0 and 1 at the same time (including all intermediate states).

Imagine that a qubit is a coin, with one digital bit it could fall with the heads up or down (i.e. it could be 0 or 1), but when we talk about qubits, the coin could spin on the table without knowing if it came out heads or tails.

Let’s talk about quantum entanglement

Albert Einstein, together with Boris Podolsky and Nathan Rosen, proposed the principle of quantum entanglement. And it is that two quantum systems, the qubits are correlated in their states (which makes them have the same state).

If we continue with the example we mentioned before, when two coins rotate at the same time, they will have the same state. Once the coin falls to one side or the other, the quantum entanglement would be broken.

One of the advantages of qubits is that they can adopt several states simultaneously. This makes them able to perform calculations much more quickly.

Despite this is the theory, in practice the rest of the conditions have to be met:

  • A correct quantum entanglement.
  • A very low error rate.
  • No interference.

The challenge often lies in being able to maintain accuracy. In this way, an error correction system has been developed.

Are we going to replace conventional computers with quantum ones?

The answer is quick, and it is that quantum computers will not replace conventional ones, the reason being that they are not always necessary. 

So far, it has not been possible to prove that a quantum computer can operate stably for hours, days or even years. Currently, programmers use programs only to perform tests with this type of computer, but not to solve other global tasks beyond quantum mechanics.