The development of modern quantum technologies takes place in four core areas. Although these have very different objectives, they are closely linked. They are all based on [[Quantum Information|quantum information]]. Here, we present the four core areas: [[Quantum Computer| quantum computing]], [[quantum simulation]], [[quantum communication]] and [[Quantum Metrology|quantum metrology]]. ![[quantum_technology.excalidraw.light.svg]] Let us have a quick look at the four core areas: 1. [[Quantum Computer|Quantum computers]] should one day make it possible to solve complex problems that our current computers fail hopelessly at. They make use of quantum effects such as [[Superposition|superposition]] and [[entanglement]] to solve selected mathematical problems much more efficiently than classical computers. Classical computers include all the computers we are used to --- laptops, desktop PCs, but also supercomputers in large data centers. An example of a mathematical problem where quantum computers are superior to classical computers according to our current knowledge is [[Prime Factorization|prime factorization]]. This plays a central role in important [[Asymmetric Encryption|encryption methods]] that we use to [[Encryption|encrypt]] our data today. Since the technical implementation of quantum computers is very complex, only small prototypes exist to date. With quantum hardware in early 2025, no practically relevant problems can be [[Quantum Advantage|solved faster]] with them than with a classic computer. Despite technical challenges, interest from science, industry and governments worldwide is growing, leading to increased investment in research and development of quantum computers. 2. Most [[Quantum Simulation|quantum simulators]] are used to replicate [[Quantum Many-Body System|complex quantum systems]] under controlled conditions. Scientists hope that this will give them a better understanding, for example of certain materials or chemical processes. The development of [[Quantum Simulation|quantum simulators]] is an important interim goal for many researchers before there are good quantum computers. However, a simulator is less universally applicable than a quantum computer. 3. In [[quantum communication]], information is transmitted using [[Qubit|qubits]]. These are the carriers of quantum-mechanically encoded information. Quantum communication enables data transmissions where an interception by a third party can be detected. As we know from spy films and the real world, many conventional communication channels are not particularly secure. This is different with quantum data because quantum information [[No-Cloning Theorem|cannot be copied]] without changing the original. This is already a first indication that the quantum world is good for some surprises --- and this is by no means just theory. In practice, election results were sent for the first time in Switzerland in 2007 with the help of quantum cryptography and communication. Quantum communication also paves the way for [[Quantum Network|quantum networks]] and distributed quantum computing systems. 4. [[Quantum Metrology|Quantum metrology]] deals with measurements that are as precise as possible. Quantum sensors are designed to make more precise measurements of quantities such as time, length and mass than is possible with classical methods. Measurements improved by quantum physics are not a thing of the future, but are already in use. Possible applications include measuring so-called gravitational waves in physics, examining brain activity in medicine and researching individual cells in biology. >[!read]- Further Reading >- [[Quantum Mechanics]] >[!ref]- References