Quantum Dots

These tiny semiconductor structures are capable of trapping solitary electrons, which effectively results in the creation of qubits. Electrical voltages can be used to control quantum dots, enabling entanglement and qubit control. They have the benefit of being compatible with current semiconductor technologies, but they could run into issues with qubit stability and preserving coherence. Being only a few nanometers in size, they are able to glow, differing from larger particles. Moreover, the color they glow depends heavily upon the size of the nanoparticle, making it prime for qubits given its scalar metric and ability to react and adapt.

Topological Qubits

Topological qubits are a very recent and sophisticated qubit implementation that are based on the topological characteristics of matter. They depend on the production and control of anyons, which are exotic quasiparticles with non-Abelian statistics. Topological qubits are less susceptible to ambient noise locally and are theoretically resilient against some forms of mistakes. The particles have world lines, which are essentially separate paths that an object can take through time and space while remaining unique. That's important since it allows the particle's world lines to go around each other and form braids, forming logic gates which are key to the efficiency of quantum computing. However, the complexity of their interconnections makes it difficult to realize topological qubits experimentally. Scientists have not fully developed practical topological qubits yet(not to a good degree).

Photon-Based Qubits

Individual photons (light particles) are used as qubits in photon-based qubits. Optical elements including beam splitters, wave plates, and detectors can be used to control photons. Qubits based on photons are ideal for quantum communication jobs because they allow for long-distance communication across optical fibers. The direction of the particle's travel around the storage ring, a particle accelerator with magnets, determines the value of the qubit, collapsing to either 0 or 1. Strong photon-photon interactions are necessary for quantum gates, but they are still difficult to produce.