The qubits (or quantum bits,”quantum bit“) is the basic unit of information in quantum computers and was first proposed in the early 1980s by physicist Richard Feynmanwho realized the potential of quantum computing to solve complex problems in physics and chemistry. It differs from the “traditional” bit because it is not limited to having a value of 0 or 1, but can take on both values at the same time, thus drastically increasing the calculation speed of quantum computers.
What is a qubit: definition and characteristics
While a classic bit can only take on the values of 0 or 1the qubit can be 0 and 1 at the same time thanks to a phenomenon called “quantum superposition”. This property allows you to perform multiple calculations simultaneouslygreatly increasing the calculation speed. But qubits are also interesting for another fundamental characteristic, the so-called quantum entanglement: when two or more qubits are entangled (i.e. correlated), the change in state of one of them instantly affects the otherregardless of distance. These properties make qubits capable of performing calculations with an efficiency unthinkable for traditional computers.
What qubits are for and how it works: applications
Qubits are the basis of quantum computing, which promises to solve very complex problems with incredible speeds. For this reason they find applications in many fields such as:
- Molecular simulations: they allow you to model complex molecules, helping in the discovery of new drugs or materials;
- Cryptography: making communications more secure, because if someone spied on the communication they would inevitably modify the qubits and therefore make the espionage obvious;
- Optimization in a broad sense through quantum computers, from traffic management to logistics.
How a qubit is created
The qubits they are not easy to obtaingiven that quantum computers require very specific conditions, such as extremely low temperatures, close to absolute zero (–273 °C). At these temperatures, some materials become superconducting, meaning they allow electrons to pass through without any resistance. This behavior is crucial to making qubits, which must maintain quantum coherence to perform calculations correctly.
Even in Italy we managed to manufacture them, precisely at Bruno Kessler Foundation of Trento, where a team of researchers led by Federica Mantegazzini replicated the energy levels of an atom in an electrical circuit, creating a qubit operating at very low temperatures. Their work could lead to new advances in quantum computers and in information technology in general.
