Quantum Computers

Quantum Computers, unlike common computers, are devices that use QUBits instead of bits. Qubits have a superposition, which means that they can be both 0 and 1 at the same time before testing its value. Another property of QUBits is entanglement, which means that one QUBit can instantly manipulate the reaction of the other QUBit, even if they are apart from each other (As far apart as being at the opposite sides of the universe). Entanglement is done by Quantum gates. This technology allows the Quantum devices to run tests, simulations and do research more efficiently, such as database searching, database encrypting (For banking and personal digital information applications) and Quantum simulations.

  • Aufruhr auf der Nanoskala – Topologische Isolatoren leisten Widerstand

    Die kleine Kante ist nur rund fünf Atomschichten dick, doch sie reicht aus, um eine feste Theorie ins Wanken zu bringen: An Topologischen Isolatoren, den Hoffnungsträgern z.B. für Quantencomputer, forschen Projektleiter Dr. Christian Bobisch und Sebastian Bauer vom Center for Nanointegration (CENIDE) der Universität Duisburg-Essen (UDE), gefördert von der Deutschen Forschungsgemeinschaft. Sie wiesen nach, dass Kanten auf der Oberfläche die elektrische Leitfähigkeit beeinflussen, indem sie wie kleine Widerstände wirken – was aber gleichzeitig die Tür zu einem präzisen elektronischen Oberflächendesign öffnet. Ihre Erkenntnisse erschienen soeben in der Fachzeitschrift „Nature Communications“.

  • Controlling Quantum States Atom by Atom

    Controlling Quantum States Atom by Atom | Using the tip of a scanning tunnel microscope, a single xenon atom (yellow) is being moved from a quantum box (blue), thus specifically altering its electronic quantum state. (Image: University of Basel, Department of Physics)

    An international consortium led by researchers at the University of Basel has developed a method to precisely alter the quantum mechanical states of electrons within an array of quantum boxes. The method can be used to investigate the interactions between various types of atoms and electrons, which is essential for future quantum technologies, as the group reports in the journal Small.

  • Exotischer Materiezustand: "Flüssige" Quantenspins bei tiefsten Temperaturen beobachtet

    Exotischer Materiezustand Flüssige Quantenspins bei tiefsten Temperaturen beobachtet | Im Kristallgitter von Kalzium-Chrom-Oxid gibt es sowohl ferromagnetische Wechselwirkungen (grüne und rote Balken) als auch antiferromagnetische (blaue Balken). Abbildung: HZB

    Ein Team am HZB hat experimentell eine sogenannte Quanten-Spinflüssigkeit in einem Einkristall aus Kalzium-Chrom-Oxid nachgewiesen. Dabei handelt es sich um einen neuartigen Materiezustand. Das Besondere an dieser Entdeckung: Nach gängigen Vorstellungen war das Quantenphänomen in diesem Material gar nicht möglich. Nun liegt eine Erklärung vor. Die Arbeit erweitert das Verständnis von kondensierter Materie und könnte auch für die zukünftige Entwicklung von Quantencomputern von Bedeutung sein. Die Ergebnisse sind nun in Nature Physics veröffentlicht.

  • First experimental quantum simulation of particle physics phenomena

    First experimental quantum simulation of particle physics phenomena | Physicists have simulated the creation of elementary particle pairs out of the vacuum by using a quantum computer. IQOQI/Harald Ritsch

    Physicists in Innsbruck have realized the first quantum simulation of lattice gauge theories, building a bridge between high-energy theory and atomic physics. In the journal Nature, Rainer Blatt‘s and Peter Zoller’s research teams describe how they simulated the creation of elementary particle pairs out of the vacuum by using a quantum computer.

  • First quantum photonic circuit with electrically driven light source

    Graphic representation of part of a chip, showing with photon source, detector and waveguides Illustration: Münster University/Wolfram Pernice

    Optical quantum computers can revolutionize computer technology. A team of researchers led by scientists from Münster University and KIT now succeeded in putting a quantum optical experimental set-up onto a chip. In doing so, they have met one of the requirements for making it possible to use photonic circuits for optical quantum computers.

  • Further Improvement of Qubit Lifetime for Quantum Computers

    Illustration of the filtering of unwanted quasiparticles (red spheres) from a stream of superconducting electron pairs (blue spheres) using a microwave-driven pump. Philip Krantz, Krantz NanoArt

    New Technique Removes Quasiparticles from Superconducting Quantum Circuits - An international team of scientists has succeeded in making further improvements to the lifetime of superconducting quantum circuits. An important prerequisite for the realization of high-performance quantum computers is that the stored data should remain intact for as long as possible. The researchers, including Jülich physicist Dr. Gianluigi Catelani, have developed and tested a technique that removes unpaired electrons from the circuits. These are known to shorten the qubit lifetime (to be published online by the journal Science today.

  • 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.

  • One-dimensional light on graphene

    Nanostructured graphene illuminated with light holds potential for a wide range of applications in photonics and optoelectronics, including infrared and terahertz photodetectors, sensors, reflect arrays or modulators. Development of graphene nanopatterning technology has in recent years enabled the construction of such devices that hold promise for a quick transfer from scientific labs to the marketplace. Now scientists have carefully mapped, with nanoresolution, the structure of light on graphene nanoresonators, observing light that is confined to extremely small volumes at the edges of the nanostructures. The nearly 1D form of this light is expected to lead to novel device applications, for example to efficient control of quantum emitters, a sort of “bit” in future quantum computers.

  • Quantum processor for single photons

    Quantum processor for single photons | Illustration of the processes that take place during the logic gate operation: The photons (blue) successively impinge from the right onto the partially transparent mirror of a resonator which contains a single rubidium atom (symbolised by a red sphere with yellow electron orbitals). The atom in the resonator plays the role of a mediator which imparts a deterministic interaction between the two photons. The diagram in the background represents the entire gate protocol. Graphic: Stephan Welte, MPQ, Quantum Dynamics Division

    MPQ-scientists have realised a photon-photon logic gate via a deterministic interaction with a strongly coupled atom-resonator system.

    "Nothing is impossible!" In line with this motto, physicists from the Quantum Dynamics Division of Professor Gerhard Rempe (director at the Max Planck Institute of Quantum Optics) managed to realise a quantum logic gate in which two light quanta are the main actors. The difficulty of such an endeavour is that photons usually do not interact at all but pass each other undisturbed. This makes them ideal for the transmission of quantum information, but less suited for its processing. The scientists overcame this steep hurdle by bringing an ancillary third particle into play: a single atom trapped inside an optical resonator that takes on the role of a mediator. “The distinct feature of our gate implementation is that the interaction between the photons is deterministic”, explains Dr. Stephan Ritter. “This is essential for future, more complex applications like scalable quantum computers or global quantum networks.” (Nature, Advance Online Publication, 6 July 2016, DOI: 10.1038/nature18592).

  • Single crystal growth in hot air: nice and easy

    Schematic of the growth setup. The desired single crystals grow from separated educts at 1020°C via vapor transport. The condensation takes place at spikes placed in between the starting materials. © University of Augsburg/EP VI

    Physicists from Augsburg University together with colleagues from Oxford report on a novel method for the growth of lithium-based transition metal oxides. Augsburg/PhG/KPP -The synthesis of ceramic crystals often requires very complicated methods. Starting materials in form of powders have to be mixed, pressed and pre-reacted in order to allow for single crystal growth from the melt at elevated temperatures. Or samples are grown from solution or chemical vapor transport in complex processes. However, so far none of the established methods yields single crystals of lithium iridate - despite the great interest in this material that was initiated by the prediction of highly unusual magnetic properties.

  • The Atom Without Properties

    The microscopic world is governed by the rules of quantum mechanics, where the properties of a particle can be completely undetermined and yet strongly correlated with those of other particles. Physicists from the University of Basel have observed these so-called Bell correlations for the first time between hundreds of atoms. Their findings are published in the scientific journal Science.