What is Quantum Computing? – Quantum Computing Explained – AWS

No one has shown the best way to build a fault-tolerant quantum computer, and multiple companies and research groups are investigating different types of qubits. We give a brief example of some of these qubit technologies below.

A gate-based quantum computer is a device that takes input data and transforms it according to a predefined unitary operation. The operation is typically represented by a quantum circuit and is analogous to gate operations in traditional electronics. However, quantum gates are totally different from electronic gates.

Trapped ion quantum computers implement qubits using electronic states of charged atoms called ions. The ions are confined and suspended above the microfabricated trap using electromagnetic fields. Trapped-ion based systems apply quantum gates using lasers to manipulate the electronic state of the ion. Trapped ion qubits use atoms that come from nature, rather than manufacturing the qubits synthetically.

Superconductivity is a set of physical properties that you can observe in certain materials like mercury and helium at very low temperatures. In these materials, you can observe a characteristic critical temperature below which electrical resistance is zero and magnetic flux fields are expelled. An electric current through a loop of superconducting wire can persist indefinitely with no power source.

Superconducting quantum computing is an implementation of a quantum computer in superconducting electronic circuits. Superconducting qubits are built with superconducting electric circuits that operate at cryogenic temperatures.

Neutral atom qubit technology is similar to trapped ion technology. However, it uses light instead of electromagnetic forces to trap the qubit and hold it in position. The atoms are not charged and the circuits can operate at room temperatures

A Rydberg atom is an excited atom with one or more electrons that are further away from the nucleus, on average. Rydberg atoms have a number of peculiar properties including an exaggerated response to electric and magnetic fields, and long life. When used as qubits, they offer strong and controllable atomic interactions that you can tune by selecting different states.

Quantum annealing uses a physical process to place a quantum system's qubits in an absolute energy minimum. From there, the hardware gently alters the system's configuration so that its energy landscape reflects the problem that needs to be solved. The advantage of quantum annealers is that the number of qubits can be much larger than those available in a gate-based system. However, their use is limited to specific cases only.

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What is Quantum Computing? - Quantum Computing Explained - AWS