Scientists of the FU Berlin, the Universidade Federal do Rio de Janeiro, and the MPQ develop a new certification method for photonic quantum simulators.
In the past 20 years, the development of devices that exploit the laws of quantum physics has made impressive progress. New quantum technologies promise a variety of exciting applications, for example in the field of quantum information processing or for the safe encoding of data. Hence, the commercial use of quantum devices has now become feasible.
There is, however, a severe obstacle to overcome: the lack of practical tools for certifying the functionality of the devices. This prevents the transformation of complex laboratory set-ups into commercial products. Now, an international team of scientists has proposed a new certification method that applies to photonic devices in which light quanta serve as the carriers of quantum information.
This new method, developed by Prof. Dr. Jens Eisert (Freie Universität Berlin), Prof. Dr. Leandro Aolita (Universidade Federal do Rio de Janeiro), Dr. Christian Gogolin, postdoctoral scientist in the Theory Division at MPQ (Garching) and Research Fellow at ICFO (Barcelona), as well as Martin Kliesch (Freie Universität Berlin), is characterized by its high reliability and simplicity (Nature Communications, 18th November 2015, DOI 10.1038/NCOMMS9498).
It is an important step towards exploiting the quantum mechanical behaviour of quantum many-body systems in a controlled way.
Quantum simulation as well as quantum cryptography has become increasingly important in the past years. The ultimate goal of all these efforts is a “general purpose computer”, a device with the power to solve all kinds of different problems, and outperforming any classical computer in terms of speed.
How to achieve this goal remains a question of active research at present. There is, however, a kind of intermediate stage that is now within reach: so-called quantum simulators. By making use of quantum effects, these devices can at least solve certain specific tasks that cannot be treated efficiently with classical methods. They are fast, but not universal.
Quantum optics represents a platform for the implementation of quantum simulators. Here the quantum mechanical properties of light quanta (so-called photons), such as entanglement and superposition, are being used. But how can one make sure that machines that rely on the use of microscopic particles work the way they are supposed to? “Certification is very difficult, in particular in case of non-universal quantum computers,” Dr. Christian Gogolin explains.
“This is, because quantum simulators are limited in their capability to perform calculations. So you cannot run any kind of certification program. Instead, the program has to be tailored according to the specific properties of the quantum simulator.”
The problem of certification can be understood in terms of a game in which one very powerful player – let’s call him Merlin – challenges a much less powerful opponent, let’s call him Arthur. Merlin claims to be in possession of a quantum simulator, but Arthur is doubtful.
He wants to have a proof that this is true, and that Merlin’s quantum simulator is indeed capable of solving problems that exceed his (Arthur’s) own abilities. The goal is to find a way for Arthur that allows him – despite of his limited resources – to check whether Merlin owns a functioning quantum simulator.
In their publication the scientists propose a test that offers this kind of certification for a variety of optical quantum simulators. For one, Arthur has to be able to detect and characterize single photons. Second, he has to use a classical computer in order to check Merlin’s solutions and make sure that his quantum simulator delivers the correct values. After a calculable number of “rounds” in this game Arthur will know with a certainty of say 99.9 % whether Merlin is able to prepare a selected quantum state to a selected precision.
The experimental techniques that are available today provide a surprisingly large number of potential applications of quantum effects. That makes it all the more important to prove that the methods live up to their claims. “Up to now, most of the effort went into the realization of quantum technologies whereas certification received hardly any attention”, Prof. Jens Eisert elaborates.
“Now we have reached a point where this bottleneck hinders further experimental progress. The method we propose is rather simple, yet very reliable. Though it is tailored for optical devices, it also contributes to finding a general solution for the problem of certification.” Olivia Meyer-Streng
Leandro Aolita, Christian Gogolin, Martin Kliesch, and Jens Eisert
Reliable quantum certification for photonic quantum technologies
Nature Communications, 18 November 2015, DOI 10.1038/NCOMMS9498
Prof. Dr. J. Ignacio Cirac
Honorary Professor TU München and
Director at the Max Planck Institute of Quantum Optics
Hans-Kopfermann-Str. 1, 85748 Garching, Germany
Phone: +49 (0)89 32 905 -705/-736 / Fax: -336
Dr. Christian Gogolin
ICFO - The Institute of Photonic Sciences
Mediterranean Technology Park,
Av. Carl Friedrich Gauss, 3,
08860 Castelldefels (Barcelona), Spanien
Phone: +34 935 54 22 37
Dr. Olivia Meyer-Streng
Press & Public Relations
Max Planck Institute of Quantum Optics, Garching, Germany
Phone: +49 (0)89 32 905 -213
Dr. Olivia Meyer-Streng | Max-Planck-Institut für Quantenoptik
Magnetic nano-imaging on a table top
20.04.2018 | Georg-August-Universität Göttingen
New record on squeezing light to one atom: Atomic Lego guides light below one nanometer
20.04.2018 | ICFO-The Institute of Photonic Sciences
University of Connecticut researchers have created a biodegradable composite made of silk fibers that can be used to repair broken load-bearing bones without the complications sometimes presented by other materials.
Repairing major load-bearing bones such as those in the leg can be a long and uncomfortable process.
Study published in the journal ACS Applied Materials & Interfaces is the outcome of an international effort that included teams from Dresden and Berlin in Germany, and the US.
Scientists at the Helmholtz-Zentrum Dresden-Rossendorf (HZDR) together with colleagues from the Helmholtz-Zentrum Berlin (HZB) and the University of Virginia...
Novel highly efficient and brilliant gamma-ray source: Based on model calculations, physicists of the Max PIanck Institute for Nuclear Physics in Heidelberg propose a novel method for an efficient high-brilliance gamma-ray source. A giant collimated gamma-ray pulse is generated from the interaction of a dense ultra-relativistic electron beam with a thin solid conductor. Energetic gamma-rays are copiously produced as the electron beam splits into filaments while propagating across the conductor. The resulting gamma-ray energy and flux enable novel experiments in nuclear and fundamental physics.
The typical wavelength of light interacting with an object of the microcosm scales with the size of this object. For atoms, this ranges from visible light to...
Stable joint cartilage can be produced from adult stem cells originating from bone marrow. This is made possible by inducing specific molecular processes occurring during embryonic cartilage formation, as researchers from the University and University Hospital of Basel report in the scientific journal PNAS.
Certain mesenchymal stem/stromal cells from the bone marrow of adults are considered extremely promising for skeletal tissue regeneration. These adult stem...
In the fight against cancer, scientists are developing new drugs to hit tumor cells at so far unused weak points. Such a “sore spot” is the protein complex...
13.04.2018 | Event News
12.04.2018 | Event News
09.04.2018 | Event News
20.04.2018 | Physics and Astronomy
20.04.2018 | Interdisciplinary Research
20.04.2018 | Physics and Astronomy