Quantum Physics

  • Deep Insight Into Interfaces

    Film of lanthanum cobalt oxide shows a sequence of positively and negatively charged atomic layers. Without electronic reconstruction an enormous electrostatic field would form between the layers Graphic: J.E. Hamann-Borrero & Vladimir Hinkov

    Interfaces between different materials and their properties are of key importance for modern technology. Together with an international team, physicists of Würzburg University have developed a new method, which allows them to have an extremely precise glance at these interfaces and to model their properties.

  • Kaiserslautern physicists observe diffusion of individual atoms in light bath

    First author Farina Kindermann and Professor Artur Widera in front of a quantum gas experi-mental setup for investigations on single atoms. University of Kaiserslautern/Thomas Koziel

    In a combination of experiments and theory the diffusion of individual atoms in periodic systems was understood for the first time. The interaction of individual atoms with light at ultralow temperatures close to the absolute zero temperature point provides new insights into ergodicity, the basic assumption of thermodynamics. Quantum physicists at University of Kaiserslautern have published their results together with colleagues in the renowned scientific journal “Nature Physics”.

  • Matter-antimatter symmetry confirmed with precision record

    Sketch of the experimental setup used at CERN for the determination of the antiproton-to-electron mass ratio. Graphic: Masaki Hori

    CERN experiment sets precision record in the measurement of the antiproton to electron mass ratio using a new innovative cooling technique. According to the Standard Model of elementary particle physics, to each particle exists an antiparticle that is supposed to behave exactly the same way. Thus, “anti-people” in an “anti-world” would observe the same laws of physics, or make the same experiences in general, as we do. This postulate is, however, difficult to prove, since it is almost impossible to perform measurements on antimatter: whenever an antiparticle meets is matter-counterpart, both particles annihilate, accompanied by the creation of energy.

  • New Quantum States for Better Quantum Memories

    An artificial diamond under the optical microscope. The diamond fluoresces because due to a number of nitrogen defects. TU Wien

    How can quantum information be stored as long as possible? An important step forward in the development of quantum memories has been achieved by a research team of TU Wien. Conventional memories used in today’s computers only differentiate between the bit values 0 and 1. In quantum physics, however, arbitrary superpositions of these two states are possible. Most of the ideas for new quantum technology devices rely on this “Superposition Principle”. One of the main challenges in using such states is that they are usually short-lived. Only for a short period of time can information be read out of quantum memories reliably, after that it is irrecoverable.

  • Observing the birth of a spectral line

    Absorption in a helium as it depends on the photon energy of the exciting extreme-ultraviolet flash of light and the time delay to the ionizing near-infrared laser pulse acting as a cut-off gate. graphics: MPIK

    Ultrashort intense laser pulses cut into a fundamental quantum phenomenon.
    For the first time, physicists managed to observe in real time how an atomic spectral line emerges within the incredibly short time span of a few femtoseconds, verifying a theoretical prediction. This has been possible by applying a very fast temporal switch: An intense laser pulse cuts off the natural decay shortly after excitation by a preceding laser pulse. The build-up of the asymmetric Fano line shape of two quantum-mechanically interfering electrons in the Helium atom is measured by varying the time delay between the two laser pulses.

  • Quantum Particles Form Droplets

    Quantum droplets may preserve their form in absence of external confinement because of quantum effects. IQOQI/Harald Ritsch

    In experiments with magnetic atoms conducted at extremely low temperatures, scientists have demonstrated a unique phase of matter: The atoms form a new type of quantum liquid or quantum droplet state. These so called quantum droplets may preserve their form in absence of external confinement because of quantum effects. The joint team of experimental physicists from Innsbruck and theoretical physicists from Hannover report on their findings in the journal Physical Review X.

  • Speeding up electronics with light

    Light pulses generate Multi-PHz electric current in bulk solids. The emitted extreme ultraviolet radiation allows scientists to record these electric currents in real time. Graphic: Research Group Attoelectronics, MPQ

    By using ultrafast laser flashes, scientists at Max Planck Institute of Quantum Optics generated and measured the fastest electric current inside a solid material. The electrons executed eight million billion oscillations per second, setting a record of human control of electrons inside solids! The performance of modern electronic devices such as computers or mobile phones is dictated by the speed at which electric currents can be made to oscillate inside their electronic circuits.

  • Ultracold atoms in a "Rydberg-dress"

    Ultracold atoms in a Rydberg dress picture1 | Fig. 1: From the starting state densely filled with atoms (left), a ring-like structure emerges due to the long range interaction (right). Graphic: MPQ, Quantum Many-Body Systems Division

    Scientists at the MPQ (Garching) and MPIPKS (Dresden) have developed a novel technique to let atoms interact over large distances.

    Many properties of our everyday world can be explained if atoms are thought of as small, solid marbles, which feel each other only if brought in direct contact with each other. The temperature of the air surrounding us, for example, is the result of uncountable, continuously occurring collisions between its constituents. Contrary to this, we also know effects which arise from the interplay between two distant objects. Well-known examples are two magnets which can affect each other also at quite a distance, or the formation of a salt crystal as a regular arrangement of positively charged sodium and negatively charged chlorine ions, which are bound together at large distances by electrical attraction.

  • Ultrashort and Extremely Precise

    Innsbruck physicists observe a surprising quantum effect when short light pulses interact with matter. Patrick Maurer

    A group of theoretical physicists headed by Oriol Romero-Isart from the Institute for Quantum Optics and Quantum Information and the University of Innsbruck observes a surprising quantum effect when short light pulses interact with matter. In the future, this effect may be used for developing a completely new type of far-field light nanoscopes.