IQOQI Vienna Search

Filter

Die Suche über die Website www.oeaw.ac.at ist eine Facettensuche:
Im ersten Eingabefeld können Sie einen Suchbegriff eingeben und mit den darunterliegenden Filtern (Facetten) das Ergebnis eingrenzen.

Treffen Sie eine Auswahl bei der Facette Person, um gezielt Mitglieder bzw. Mitarbeiter/innen zu finden. Bei der Facette Seitentyp können Sie "Events" für eine Suche nach ÖAW-Veranstaltungen, "News" für Neuigkeiten aus der ÖAW und "Seiten" für fixe Seiten innerhalb der ÖAW-Website auswählen.

  • Seite
    Quantum Entanglement in High-Dimensional Systems
    in more than 100 dimensions [1]. Furthermore, quantum entanglement with up to 10010ħ of angular momentum has been achieved in our labs, showing that systems with very large quanta can still possess the puzzling properties of the quantum world [2]. Figure 2: Demonstration of high-order OAM mode generation with SPMs and an intense laser. In parallel to increasing the dimensionality of the quantum systems, we also increase the complexity of those. We do so by simultaneously ...
  • Seite
    Macroscopic Entanglement Witnesses
    xxx-Heisenberg spin-1/2 (a, top) and spin 1 (b, bottom) chains. The black solid curves are temperature dependences of the zero-field magnetic susceptibilities per particle and the red curves are “entanglement witnesses”. All points below of the intersection points to the left (below the critical temperatures) indicate the existence of entanglement in the solids. [1] Č. Brukner and V. Vedral, Macroscopic Thermodynamical Witnesses of Quantum Entanglement, Preprint at ...
  • Seite
    Quantum Theory on Indefinite Causal Structures
    called causally separable if it can be decomposed as a convex combination of causally ordered processes, otherwise it is causally nonseparable. Recently, we have developed a method for certifying causal separability, which is based on “causal witnesses” [2, see also our video ]. Causally nonseparable processes can rise to correlations that can violate “causal inequalities” which are satisfied if the events are ordered according to a fixed causal order [1,3]. This is a direct ...
  • Seite
    Reconstructions of Quantum Theory
    strategy (it is taken from another publication [3] and the labelling is not exactly fitting, but the overall strategy is the same). For the details, see our paper [1] or the Les Houches lecture notes [2]. We start by considering a generalized bit in a GPT that satisfies our postulates, i.e. a system with n=2 distinguishable states. A priori, its state space could be described by any convex set of any dimension d (top left). However, the subspace axiom gives us some ...
  • Seite
    The collapse engine and other adventures with energy
    power a 40-Watt lightbulb indefinitely. In the more than probable event that spontaneous collapse models are wrong and energy is locally conserved, the focus of human activities should be delaying the exhaustion of energy resources. In this line, in [2] we relate the maximum precision achievable in a quantum measurement with the average energy of the corresponding measurement apparatus. In order to probe a quantum system, we make it interact with a measurement device, see ...
  • Seite
    Quantum Reference Frames, Gauge Theories, and Locality
    subtle restrictions of recently proposed quantum covariance principles [9]. References [1] F. Giacomini, E. Castro-Ruiz, and Č. Brukner, Quantum mechanics and the covariance of physical laws in quantum reference frames , Nat. Commun. 10 , 494 (2019). [2] A. Vanrietvelde, P. A. Höhn, F. Giacomini, and E. Castro-Ruiz, A change of perspective: switching quantum reference frames via a perspective-neutral framework , Quantum 4 , 225 (2020). [3] L. Loveridge, P. Busch, and T. ...
  • Seite
    Cosmic Bell Experiments
    issue in all previous Bell experiments is the quality of the random numbers, which are used to decide the setting parameter on both photons independently. In our “loophole-free” experiment [1], we did this with high quality random number generators [2], which, to the best of our knowledge, are among the best random number generators currently available. Yet, as has been pointed out in the early days of this experiment, such random number generators could in principle still ...
  • Seite
    Quantum Interference and Indistinguishability
    n and coherence of photons both at a fundamental level as well as with respect to possible applications. Based on the above phenomenon, we developed a quantum-imaging scheme, in which photons that pass through the object do not need to be detected [2]. Recently, we demonstrated a method to access information about the momentum correlation between two photons by detecting only one of them, given two identical sources are available [3]. We also showed that the concept of ...
  • Seite
    Satellite Based Quantum Communication
    key distribution based on a decoy state protocol [1] intercontinentally between optical ground stations in Europe and China. The satellite – named after the Chinese philosopher “Micius” – has been developed and constructed by our partners in China [2,3] and is in-orbit since 2016. Our group has developed the required technology for optical ground stations in Europe and executed the necessary adaptations. In 2017 we have performed downlink experiments to the laser ranging ...
  • Seite
    Quantum-to-Classical Transition
    realism and deterministic laws can emerge out of fundamentally random quantum events. Finally, we demonstrate that there exist “non-classical dynamics” that enable a violation of macroscopic realism even under classical coarse-grained measurements [2]. The question why we then normally do not see such violations arises again. We suggested that the reason for this is that non-classical time evolutions are of high computational complexity. Figuratively, this means that if ...