University of Vienna

Quantum Correlations at the Macro-Scale: Can We See Them?

One of the most fundamental features of quantum physics is Bell nonlocality: the fact that the predictions of quantum mechanics cannot be explained by any local (classical) theory. This has remarkable conceptual consequences and far-reaching applications in quantum information. However, in our everyday experience, macroscopic objects seem to behave according to the rules of classical physics, and the correlations we see are local. Is this really the case, or can we challenge this view? In a recent paper in Physical Review Letters, scientists from the University of Vienna and the Institute of Quantum Optics and Quantum Information (IQOQI) of the Austrian Academy of Sciences have shown that it is possible to fully preserve the mathematical structure of quantum theory in the macroscopic limit. This could lead to observations of quantum nonlocality at the macroscopic scale.

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Getting the Output Right: Team Takes to Task Achieving Full Advantage of Quantum Computing

Quantum computers are advancing at a rapid pace and are already starting to push the limits of the world’s largest supercomputers. Yet, these devices are extremely sensitive to external influences and thus prone to errors which can change the result of the computation. This is particularly challenging for quantum computations that are beyond the reach of our trusted classical computers, where we can no longer independently verify the results through simulation. “In order to take full advantage of future quantum computers for critical calculations we need a way to ensure the output is correct, even if we cannot perform the calculation in question by other means,” says Chiara Greganti from the University of Vienna. 

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