Quantum technologies are intended to provide solutions for the major challenges of our time: for complex interrelationships in the field of energy transition, drug research or tap-proof communication. They also form the basis for quantum computers with unprecedentedly high computing power.
Quantum technologies are intended to provide solutions for the major challenges of our time: for complex interrelationships in the field of energy transition, drug research or tap-proof communication. They also form the basis for quantum computers with unprecedentedly high computing power.
It has not yet been possible to create sufficiently robust systems. Scientists at Paderborn University have now succeeded in building Europe's largest sampling-based quantum computer, the PaQS (Paderborn Quantum Sampler). This has been built by Paderborn University staff together with partners Menlo Systems, Fraunhofer IOF Jena and Swabian Instruments as part of a funding initiative by the Federal Ministry of Education and Research. A second sampling-based quantum computer with cloud access is due to go into operation in Jena shortly.
One technical challenge is that quantum computers are sensitive to system imperfections. Scientists around the world are working on this on various experimental platforms, each with different advantages and disadvantages. Photonic networks, for example, can be operated at room temperature and implemented in miniaturized, programmable circuits. Photonic quantum computers use light to perform quantum computations, while other approaches to quantum computing are based on e.g. superconducting qubits or trapped ions. The advantages of photonic quantum computers include scalability and high clock rates. However, they have to contend with optical losses. The project is tackling this problem with Germany's leading expertise in integrated photonics. The research team has succeeded in creating a so-called 'Gaussian boson sampler' consisting of scalable components. Many components first had to be newly developed for this. Any desired configuration is possible with this sampling machine.
'Squeezed' light
Gaussian boson sampling is a model of photonic quantum computing that has gained attention as a platform for building quantum devices. The researchers use a fully programmable and integrated interferometer with which any desired configuration can be implemented. Light particles are distributed and directed in a network of optical fibers. At the output of the network, they measure where the photons emerge from the network. According to the scientists involved, this could be relevant for solving protein folding problems or calculating molecular states in the context of drug research, for example.
Quantum mechanical phenomena such as squeezing and the superposition or entanglement of photons are responsible for the high computing power of quantum computers. It always starts with the generation of a specific quantum resource. In the case of Gaussian boson sampling, this resource is known as 'squeezing' or 'squeezed light', whose quantum mechanical properties have been manipulated and thus made usable.
