Both conventional computers and quantum computers perform functions with bits, but they differ significantly in other ways. A bit in a standard computer can only assume two states, namely “0” and “1”. However, a quantum bit or qubit of a quantum computer assumes both states simultaneously in a superposition. This ensures that the computing capacity of a quantum computer is much higher than that of a conventional computer because data can be processed simultaneously. And with each additional qubit, the computing power grows exponentially.
Superposition, which is the overlapping of states, also leads to qubit interference. This means that the states reinforce or weaken each other. Another concept that allows quantum computing to deliver high performance is the entanglement of several qubits. As a result, the states are no longer independent, but are coupled together – if one qubit changes, so does the other.
These three features of quantum computing (superposition, interference and entanglement) ensure that quantum computers can process data more efficiently. This enables them to work with complicated datasets and, in the future, means that they will be able to perform previously unsolvable computational tasks.
Unlike conventional computers, the processes in quantum computers do not take place at the electronic level, but instead at the physical particle level. Special frameworks are necessary so that the quantum mechanical properties of a quantum computer can be maintained. For example, quantum computers based on superconducting qubits consist of several chambers, the lowest of which is cooled to a temperature close to absolute zero (-273 °C). Even minor temperature changes or radiation could influence the qubits. As yet, it has only been possible to actually keep a qubit in the state of superposition for a short time – but maintaining this state is a prerequisite for quantum computing to function properly. The number of qubits is also currently very limited. In a few years, there will probably be quantum computers with thousands of qubits, but this still may not be enough for complex calculations.
This means that a lot of fundamental research is still necessary at this stage so that quantum technologies can be used reliably in the future. However, interest in quantum computing is growing, given the potential for quantum technology to make groundbreaking developments in many industries due to its phenomenal computing power.