There are several types of qubits that have been proposed or implemented in quantum computing platforms. This is a non-exhaustive list of the most well-known:
- Superconducting qubits are the most common type of qubit in current quantum computing systems. Superconducting qubits are based on the Josephson junction, which is a device that allows the flow of supercurrent without resistance. Examples of superconducting qubits include transmon qubits, flux qubits, and phase qubits.
- Trapped ion qubits are based on the electronic and nuclear spin states of individual ions that are trapped and manipulated using electromagnetic fields. Trapped ion qubits can be implemented using, for example, calcium, magnesium, and beryllium ions.
- Quantum dot qubits are based on the electronic spin states of electrons confined in semiconductor quantum dots. They are manipulated using electrical gates and magnetic fields.
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