In the context of quantum computing, ions refer to charged atomic or molecular particles. More specifically, ions are used as qubits in certain types of quantum computing architectures, known as ion trap quantum computers.
In ion trap quantum computing, individual ions are trapped using electromagnetic fields and manipulated to represent and process quantum information. The internal energy levels or electronic spin states of the ions are used as qubits. By precisely controlling the interactions between these ions, quantum operations such as gate operations and measurements can be performed.
The ions used in ion trap quantum computers are typically isolated from their surrounding environment to minimize decoherence and maintain the delicate quantum states. Cooling techniques, such as laser cooling, are often employed to reduce the ions' thermal motion and stabilize their quantum states.
It's worth noting that while ions are not subatomic particles themselves, they are composed of subatomic particles, namely protons, neutrons, and electrons. In the context of quantum computing, the term "ions" refers to these charged atomic or molecular species and their quantum properties are harnessed for quantum information processing.