Friday, October 25, 2013

Making the transition to the quantum world visible

Saarbrücken physicist want to make the transition to the quantum world to see

New insights into the quantum world is to open a micro-laboratory of Theoretical physicist Frank Wilhelm-Mauch and his team have developed by the University of the Saarland as a mathematical model. 100 photons, with their complex quantum mechanical relationships ("entanglement") can be studied simultaneously in the test system, as much as ever. The researchers expect new insights about the quantum computer. As the world's first group they use for their method a metamaterial, a custom-made grid of nanostructures, the light more breaks than any natural substance. Their results are published in Physical Review Letters.
A car is at the same time in one place. This place is exactly determined as well as the speed of the car: In the world in which we live, our known laws of nature. But these laws - and thus the classical physics - come in sizes smaller than an atom to a limit. Quantum particles, also called photons, or light quanta, are simultaneously in several places plus different rates - apply the laws of the quantum world: From this point everything else is in the micro world. About this transition of the end "two worlds" in which the laws of nature and start quantum laws, is little known today. "The quantum world can not simply just vermessbare, large systems transfer," explains Frank Wilhelm-Mauch. 's also a theoretical physicist and his research group have developed mathematical methods, a micro-lab, which is similar to a piece of ordinary aerial cable, but it should make it possible to study the transition between the two worlds in a controllable system. "We expect that the quantum properties of a certain size weaker or even lost entirely will. To explore this transition and specifically to investigate the quantum state specifically, we provide with our innovative concept of a very large test system 100 distinguishable photons as the basis for measurements ready, and without that a photon is lost. The cable is made ​​of superconducting material and the tests are carried out at low temperatures, "explains Professor Wilhelm-Mauch. 

So far, such undertaking are lossy: From hundred photons can today with the existing methods in the end only one can be investigated. Since the photons occupy multiple states at the same time, a measurement is also when it is done, only a tiny part of a highly complex process: The measured value always describes only one of the states. "That's why we make our test system with 100 photons as large as possible today to investigate this highly entangled, so interwoven processes. The measurements thus allow a much more accurate view of the processes, "he explains. Researchers outsmart this, the laws of classical optics. They combine the quantum optics with so-called "left-handed media," and direct this light particles through a "metamaterial". Such a grid of nanostructures is where research in classical optics for some time, have a special ability: light falling on it, is more broken than in nature, ie, such as water. The angle of refraction of light can be influenced. Also, the LAP physicists have mathematically tailored such a grid for photons of microwave radiation, which is good enough for the first time quantum optical studies. It consists of a series connection of capacitors and coils minute. With this waveguide very many photons can be packed into the smallest space and out the cable. This, the researchers want to use for quantum-optical measurements. investigate the transition to the quantum world, in particular, is of interest for the researchers. The knowledge of this interface can make the knowledge about our world precisely because even - or especially - in this case the quantum have their effects. This opens up new possibilities would open about the quantum computer, "If we find out how big of a quantum system can be up to make it even follows quantum mechanical laws, we could make the storage capacity as large as possible," said Wilhelm-Mauch. The theoretical physicist researching the international research network "Scaleqit" the quantum computer has been developed for this highly efficient microwave detector that can detect photons with one hundred percent efficiency. Currently, scientists of the universities of Karlsruhe and Syracuse (USA) on the laboratory prototype. Original publication :Daniel Egger, Frank Wilhelm-Mauch: "Multimode Circuit Quantum Electrodynamics with hybrid metamaterial transmission lines," Phys. Rev. Lett. 111, 163601 (2013) doi: 10.1103/PhysRevLett.111.163601