Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

One more step on the path to quantum computers

02.08.2010
Ultra-strong interaction between light and matter realized

Researchers around the world are working on the development of quantum computers that will be vastly superior to present-day computers. Here, the strong coupling of quantum bits with light quanta plays a pivotal role.

Professor Rudolf Gross, a physicist at the Technische Universitaet Muenchen (TUM), and his team of researchers have now realized an extremely strong interaction between light and matter that may represent a first step in this direction. The results of their research are presented in the current online issue of the journal Nature Physics.

The interaction between matter and light represents one of the most fundamental processes in physics. Whether a car that heats up like an oven in the summer due to the absorption of light quanta or solar cells that extract electricity from light or light-emitting diodes that convert electricity into light, we encounter the effects of these processes throughout our daily lives. Understanding the interactions between individual light particles – photons – and atoms is crucial for the development of a quantum computer.

Physicists from the Technische Universitaet Muenchen (TUM), the Walther-Meissner-Institute for Low Temperature Research of the Bavarian Academy of Sciences (WMI) and the Augsburg University have now, in collaboration with partners from Spain, realized an ultrastrong interaction between microwave photons and the atoms of a nano-structured circuit. The realized interaction is ten times stronger than levels previously achieved for such systems.

The simplest system for investigating the interactions between light and matter is a so-called cavity resonator with exactly one light particle and one atom captured inside (cavity quantum electrodynamics, cavity QED). Yet since the interaction is very weak, these experiments are very elaborate. A much stronger interaction can be obtained with nano-structured circuits in which metals like aluminum become superconducting at temperatures just above absolute zero (circuit QED). Properly configured, the billions of atoms in the merely nanometer thick conductors behave like a single artificial atom and obey the laws of quantum mechanics. In the simplest case, one obtains a system with two energy states, a so-called quantum bit or qubit.

Coupling these kinds of systems with microwave resonators has opened a rapidly growing new research domain in which the TUM Physics, the WMI and the cluster of excellence Nanosystems Initiative Munich (NIM) are leading the field. In contrast to cavity QED systems, the researchers can custom tailor the circuitry in many areas.

To facilitate the measurements, Professor Gross and his team captured the photon in a special box, a resonator. This consists of a superconducting niobium conducting path that is configured with strongly reflective “mirrors” for microwaves at both ends. In this resonator, the artificial atom made of an aluminum circuit is positioned so that it can optimally interact with the photon. The researchers achieved the ultrastrong interactions by adding another superconducting component into their circuit, a so-called Josephson junction.

The measured interaction strength was up to twelve percent of the resonator frequency. This makes it ten times stronger than the effects previously measureable in circuit QED systems and thousands of times stronger than in a true cavity resonator. However, along with their success the researchers also created a new problem: Up to now, the Jaynes-Cummings theory developed in 1963 was able to describe all observed effects very well. Yet, it does not seem to apply to the domain of ultrastrong interactions. ”The spectra look like those of a completely new kind of object,” says Professor Gross. “The coupling is so strong that the atom-photon pairs must be viewed as a new unit, a kind of molecule comprising one atom and one photon.

Experimental and theoretical physicists will need some time to examine this more closely. However, the new experimental inroads into this domain are already providing researchers with a whole array of new experimental options. The targeted manipulation of such atom-photon pairs could hold the key to quanta-based information processing, the so-called quantum computers that would be vastly superior to today’s computers.

The research was funded by the Deutsche Forschungsgemeinschaft (DFG) (Cluster of Excellence Nanosystems Initiative Munich and SFB 631), the European Community (EuroSQIP, SOLID), as well as the Spanish Ministry for Science and Innovation.

Pictures:

http://mediatum.ub.tum.de/?cunfold=992628&dir=992628&id=992628
Impression of the interaction between a superconducting electrical circuit and a microwave photon – Electron microscopical picture of the superconducting circuit (red: Aluminum-Qubit, grey: Niob-Resonator, green: Silicon substrate)

Publication:

Circuit quantum electrodynamics in the ultrastrong-coupling regime
T. Niemczyk, F. Deppe, H. Huebl, E. P. Menzel, F. Hocke, M. J. Schwarz, J. J. Garcia-Ripoll, D. Zueco, T. Hümmer, E. Solano, A. Marx and R. Gross
Nature Physics, published online July 25, 2010 – DOI: 10.1038/NPHYS1730
http://www.nature.com/nphys/journal/vaop/ncurrent/abs/nphys1730.html
Contact:
Prof. Dr. Rudolf Gross
Technische Universitaet Muenchen – Physics-Department and Walther-Meissner-Institute of the Bavarian Academy of Sciences
Walther-Meissner-Str. 6 
85748 Garching, Germany
Tel.: +49 89 289 14201
, Fax: +49 89 289 14206
E-Mail: Rudolf.Gross@wmi.badw.de
Kontakt:
presse@tum.de

Dr. Andreas Battenberg | EurekAlert!
Further information:
http://www.tum.de
http://www.wmi.badw.de/

More articles from Physics and Astronomy:

nachricht Illinois team finds Wigner crystal -- not Mott insulator -- in 'magic-angle' graphene
25.09.2018 | University of Illinois College of Engineering

nachricht Measuring Smallest Magnetic Fields in the Brain Using Diamond and Laser Technology
25.09.2018 | Fraunhofer-Institut für Angewandte Festkörperphysik IAF

All articles from Physics and Astronomy >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: Hygiene at your fingertips with the new CleanHand Network

The Fraunhofer FEP has been involved in developing processes and equipment for cleaning, sterilization, and surface modification for decades. The CleanHand Network for development of systems and technologies to clean surfaces, materials, and objects was established in May 2018 to bundle the expertise of many partnering organizations. As a partner in the CleanHand Network, Fraunhofer FEP will present the Network and current research topics of the Institute in the field of hygiene and cleaning at the parts2clean trade fair, October 23-25, 2018 in Stuttgart, at the booth of the Fraunhofer Cleaning Technology Alliance (Hall 5, Booth C31).

Test reports and studies on the cleanliness of European motorway rest areas, hotel beds, and outdoor pools increasingly appear in the press, especially during...

Im Focus: Scientists present new observations to understand the phase transition in quantum chromodynamics

The building blocks of matter in our universe were formed in the first 10 microseconds of its existence, according to the currently accepted scientific picture. After the Big Bang about 13.7 billion years ago, matter consisted mainly of quarks and gluons, two types of elementary particles whose interactions are governed by quantum chromodynamics (QCD), the theory of strong interaction. In the early universe, these particles moved (nearly) freely in a quark-gluon plasma.

This is a joint press release of University Muenster and Heidelberg as well as the GSI Helmholtzzentrum für Schwerionenforschung in Darmstadt.

Then, in a phase transition, they combined and formed hadrons, among them the building blocks of atomic nuclei, protons and neutrons. In the current issue of...

Im Focus: Patented nanostructure for solar cells: Rough optics, smooth surface

Thin-film solar cells made of crystalline silicon are inexpensive and achieve efficiencies of a good 14 percent. However, they could do even better if their shiny surfaces reflected less light. A team led by Prof. Christiane Becker from the Helmholtz-Zentrum Berlin (HZB) has now patented a sophisticated new solution to this problem.

"It is not enough simply to bring more light into the cell," says Christiane Becker. Such surface structures can even ultimately reduce the efficiency by...

Im Focus: New soft coral species discovered in Panama

A study in the journal Bulletin of Marine Science describes a new, blood-red species of octocoral found in Panama. The species in the genus Thesea was discovered in the threatened low-light reef environment on Hannibal Bank, 60 kilometers off mainland Pacific Panama, by researchers at the Smithsonian Tropical Research Institute in Panama (STRI) and the Centro de Investigación en Ciencias del Mar y Limnología (CIMAR) at the University of Costa Rica.

Scientists established the new species, Thesea dalioi, by comparing its physical traits, such as branch thickness and the bright red colony color, with the...

Im Focus: New devices based on rust could reduce excess heat in computers

Physicists explore long-distance information transmission in antiferromagnetic iron oxide

Scientists have succeeded in observing the first long-distance transfer of information in a magnetic group of materials known as antiferromagnets.

All Focus news of the innovation-report >>>

Anzeige

Anzeige

VideoLinks
Industry & Economy
Event News

"Boston calling": TU Berlin and the Weizenbaum Institute organize a conference in USA

21.09.2018 | Event News

One of the world’s most prominent strategic forums for global health held in Berlin in October 2018

03.09.2018 | Event News

4th Intelligent Materials - European Symposium on Intelligent Materials

27.08.2018 | Event News

 
Latest News

Establishing metastasis

25.09.2018 | Health and Medicine

Artificial intelligence to improve drug combination design & personalized medicine

25.09.2018 | Health and Medicine

Small modulator for big data

25.09.2018 | Information Technology

VideoLinks
Science & Research
Overview of more VideoLinks >>>