Superconducting qubits use superconducting circuits with Josephson junctions at ultra-low temperatures. Qubit states are stored in circuit energy levels; widely used by major quantum computing companies due to scalability and control.

Trapped ion qubits use charged atoms held by electromagnetic fields. Qubit states are stored in atomic energy levels and controlled by lasers, enabling ultra-low error rates, precise operations, and high-quality entanglement.

Photonic qubits use photons to encode data via polarization, phase, or path. Controlled with optical devices like beam splitters and phase shifters, they are ideal for quantum communication and cryptography over long distances.

Topological qubits are a proposed type of qubit that aim to store quantum information in the topological properties of exotic particles called anyons, rather than in fragile local properties like charge or energy. In theory, moving these anyons around each other in special patterns called braiding would perform quantum operations, and because the information is stored in the global structure of these braids, it would be naturally protected from many kinds of noise and errors.

Neutral atom qubits use atoms held in laser-light lattices. Qubit states are stored in atomic levels and controlled by lasers; weak environmental interaction gives long coherence and enables large-scale, stable quantum systems.

Spin qubits store data in electron or nuclear spin states (up/down). Built in semiconductor materials, they integrate well with classical chip technology and enable compact, scalable quantum processors.

Quantum dot qubits use nanoscale semiconductor dots that trap electrons. Qubit states are stored in electron charge or spin, and they are compatible with standard chip fabrication, enabling scalable quantum hardware.

NV center qubits use nitrogen-vacancy defects in diamond. Controlled with microwaves and lasers, they store quantum states in electron spins and uniquely operate at room temperature, unlike most cryogenic qubit systems.

NMR qubits use nuclear spins controlled by magnetic fields and RF pulses. They were an early quantum computing platform but face limits in speed and scalability, making large-scale systems difficult.