International research team makes important step on the path to solving certification problems
Quantum computers may one day solve algorithmic problems which even the biggest supercomputers today can’t manage. But how do you test a quantum computer to ensure it is working reliably? Depending on the algorithmic task, this could be an easy or a very difficult certification problem.
An international team of researchers has taken an important step towards solving a difficult variation of this problem, using a statistical approach developed at the University of Freiburg. The results of their study are published in the latest edition of Nature Photonics.
Their example of a difficult certification problem is sorting a defined number of photons after they have gone through a defined arrangement of several optical elements. The arrangement provides each photon with a number of transmission paths - depending on whether the photon is reflected or transmitted by an optical element.
The task is to predict the probability of photons leaving the arrangement at defined points, for a given positioning of the photons at the entrance to the arrangement. With increasing size of the optical arrangement and increasing numbers of photons sent on their way, the number of possible paths and distributions of the photons at the end rises steeply as a result of the uncertainty principle which underlies quantum mechanics - so that there can be no prediction of the exact probability using the computers available to us today.
Physical principles say that different types of particle - such as photons or electrons - should yield differing probability distributions. But how can scientists tell these distributions and differing optical arrangements apart when there is no way of making exact calculations?
An approach developed in Freiburg by researchers from Rome, Milan; Redmond, USA; Paris, and Freiburg now makes it possible for the first time to identify characteristic statistical signatures across unmeasurable probability distributions. Instead of a complete “fingerprint,” they were able to distill the information from data sets which were reduced to make them usable.
Using that information, they were able to discriminate various particle types and distinctive features of optical arrangements. The team also showed that this distillation process can be improved, drawing upon established techniques of machine learning, whereby physics provides the key information on which data set should be used to seek the relevant patterns. And because this approach becomes more accurate for bigger numbers of particles, the researchers hope that their findings take us a key step closer to solving the certification problem.
• Taira Giordani, Fulvio Flamini, Matteo Pompili, Niko Viggianiello, Nicolò Spagnolo, Andrea Crespi, Roberto Osellame, Nathan Wiebe, Mattia Walschaers, Andreas Buchleitner and Fabio Sciarrino (2018): Experimental statistical signature of many-body quantum interference. In: Nature Photonics. doi: 10.1038/s41566-018-0097-4
• Mattia Walschaers (2016): Efficient quantum transport. Thesis, University of Freiburg and Springer Theses, upcoming (Springer Thesis Award 2017).
• Mattia Walschaers, Jack Kuipers, Juan-Diego Urbina, Klaus Mayer, Malte Christopher Tichy, Klaus Richter and Andreas Buchleitner (2016): Statistical benchmark for BosonSampling. In: New Journal of Physics 18.
• Mattia Walschaers, Frank Schlawin, Thomas Wellens and Andreas Buchleitner (2016): Quantum transport on disordered and noisy networks: an interplay of structural complexity and uncertainty. In: Annual Review of Condensed Matter Physics 7, S. 223–248.
Prof. Dr. Andreas Buchleitner
Institute of Physics
University of Freiburg
Rudolf-Werner Dreier | idw - Informationsdienst Wissenschaft
Next stop Morocco: EU partners test innovative space robotics technologies in the Sahara desert
09.11.2018 | Deutsches Forschungszentrum für Künstliche Intelligenz GmbH, DFKI
A burst of ”synchronous” light
08.11.2018 | Empa - Eidgenössische Materialprüfungs- und Forschungsanstalt
Faster and secure data communication: This is the goal of a new joint project involving physicists from the University of Würzburg. The German Federal Ministry of Education and Research funds the project with 14.8 million euro.
In our digital world data security and secure communication are becoming more and more important. Quantum communication is a promising approach to achieve...
On Saturday, 10 November 2018, the research icebreaker Polarstern will leave its homeport of Bremerhaven, bound for Cape Town, South Africa.
When choosing materials to make something, trade-offs need to be made between a host of properties, such as thickness, stiffness and weight. Depending on the application in question, finding just the right balance is the difference between success and failure
Now, a team of Penn Engineers has demonstrated a new material they call "nanocardboard," an ultrathin equivalent of corrugated paper cardboard. A square...
Physicists at ETH Zurich demonstrate how errors that occur during the manipulation of quantum system can be monitored and corrected on the fly
The field of quantum computation has seen tremendous progress in recent years. Bit by bit, quantum devices start to challenge conventional computers, at least...
Scientists developed specially coated nanometer-sized vehicles that can be actively moved through dense tissue like the vitreous of the eye. So far, the transport of nano-vehicles has only been demonstrated in model systems or biological fluids, but not in real tissue. The work was published in the journal Science Advances and constitutes one step further towards nanorobots becoming minimally-invasive tools for precisely delivering medicine to where it is needed.
Researchers of the “Micro, Nano and Molecular Systems” Lab at the Max Planck Institute for Intelligent Systems in Stuttgart, together with an international...
09.11.2018 | Event News
06.11.2018 | Event News
23.10.2018 | Event News
12.11.2018 | Life Sciences
12.11.2018 | Materials Sciences
12.11.2018 | Physics and Astronomy