Qubits, the fundamental building blocks of quantum information, can be created and manipulated using a variety of physical systems or technologies, which are referred to as qubit implementations. Similar to how software in computers need a hardware to function, implementation of qubits requires certain forms of hardware or design, each with different functions. Different qubit implementations each have their own special benefits, difficulties, and characteristics. The qubit technology used has a big impact on processing power, scalability, error rates, and qubit stability in quantum computing. Let's get deeper into a few of the main qubit implementations, some of which more difficult to implement than others, but still having unique benefits.
Superconducting Qubits
Among the most popular qubit implementations are superconducting qubits. When cooled to extremely low temperatures, these small circuits composed of superconducting materials may transfer electric current without resistance. Superconductivity refers to low resistances at low temperatures, so when bits are at extreme temperatures, below freezing, electricity loses resistances. That finding has paved the way for many other discoveries within technology, but qubits especially. To be more specific, microwave pulses can be used to modify superconducting qubits, and external electromagnetic fields can be used to control them. They are simpler to manufacture and regulate since they are relatively large in comparison to other qubit systems. However, maintaining qubit coherence and stability is difficult because of their sensitivity to outside noise, one of it's only downsides.
Trapped Ion Qubits
In trapped ion qubits, specific ions are used as qubits. These ions are typically held in electromagnetic traps. Ions in short, are atoms or molecules with a net charge, either being negative or positive but not zero. That entails having a difference in the number of protons and electrons within the molecule. Entanglement and the development of qubits are made possible by the manipulation of the ions' internal energy levels by laser beams. Long qubit coherence times and high fidelity operations provided by trapped ions make them potential candidates for quantum computation. Due to the need to address and manipulate individual ions, their precise control and scalability are difficult to achieve, however.