One year of the QUEST Excellence Cluster

Opportunities and challenges for Hannover and Lower Saxony

QUEST after one year

One year ago, in October 2007, the Hannover QUEST Excellence Cluster was approved as part of the Excellence Initiative of the German Federal Government and states. Since then there has been a lot of activity in the scientific community of Hannover and Lower Saxony. QUEST brings together six institutes of the Leibniz Universität Hannover with five other research centres from Lower Saxony, in order to carry out world-class research on the quantum limit. In the four areas of quantum engineering, quantum sensors, space-time research and innovative technologies, 250 scientists will initially work on the refinement of already available and the development of future quantum technologies until 2012.

As part of this endeavour, for example, scientists will seek to answer fundamental questions of physics - including the structure and fundamental forces of our universe. Researchers will also be undertaking application-oriented work to develop new knowledge, e.g. for next generation satellite navigation systems or earth observation systems. It was the QUEST scientists, for example, who developed the most modern lasers in the world.

QUEST was approved within the framework of the Excellence Initiative of the German Federal Government in October 2007 for a period of five years. With funding of 6.5 million Euros per year, it offers participating scientists outstanding conditions for creative and innovative research work.

QUEST has already created a new infrastructure and new work groups that strategically expand the existing research competence of the Institutes. “42 new employees have already been added to the original 190. At the Leibniz Universität Hannover and its partners, 8 new professorships, 6 new junior professorships and more than 24 junior research groups and research groups have been set up by QUEST over the past twelve months,” says Prof. Dr.-Ing. Erich Barke, President of the Leibniz Universität Hannover. The eight professorships, which were announced at the beginning of March, have attracted extremely high-calibre candidates from all over the world - a clear sign of the attractiveness of QUEST and the research landscape in and around Hannover. Six professors have already been appointed. Since there is currently a shortage of highly qualified quantum researchers in Germany, the teaching at QUEST plays a vital role in the training of specialists in this area.

“One year of QUEST has generated a tremendously positive impetus throughout the Lower Saxony community of higher education institutions. But QUEST has also had a positive effect throughout Lower Saxony and Germany - as the many applications from excellent researchers from all over the world show,” says Prof. Dr. Wolfgang Ertmer, QUEST coordinator.

Even before the granting of the QUEST proposal, the participating institutes and institutions were among the most renowned in their field in Germany. The Cluster of Excellence has enhanced the international visibility and attractiveness of Hannover as a region in which to pursue scientific research.

The Excellence Initiative has shown that it is worthwhile to expand inter-university cooperation in Hannover. QUEST stands for excellence and creativity in the scientific centre that Hannover has become. One of the aims of the Hannover Science Initiative is that the Hannover site will be even more successful in continuing its Excellence Initiative," said Stephan Weil, the Mayor of Hannover.

At the Leibniz Universität Hannover the QUEST Excellence Cluster has also created administrative competition. The dual structure of cluster and faculty management has confronted the university with the challenge of finding new ways to pursue administration effectively.

The work of the QUEST Excellence Cluster has been generally well received. However, Prof. Dr. Wolfgang Ertmer, Coordinator of QUEST, is already focusing on the future. “QUEST's start-up financing is initially geared to five years. It is important to bear in mind, however, that the fruits of research in such a highly complex field as that of quantum physics need more than five years to mature. We are working with all of those involved to secure financing beyond 2012. In the least favourable case, the structural improvements that we have begun would be stalled and the overall objective of the Excellence Initiative of helping to shape the forefront of international research would be called into question.”

Prof. Dr. Karsten Danzmann, Deputy Coordinator of QUEST: “In Hannover, we have leading institutions that carry out research on individual atoms, atomic interferometers, atomic quantum sensors, lasers and atomic clocks, as well as in astronomy with gravitational waves or earth observation and geodesy. The intensive collaboration between such diverse fields will make a decisive contribution to answering scientific questions. We are on the way to holding our own with comparable international research centres, such as the National Institute of Standards and Technology, the Massachusetts Institute of Technology, or Caltech.”

Scientific institutions involved in QUEST:

• Leibniz Universität Hannover
• Institute of Quantum Optics (IQ)
• Institute of Gravitational Physics (IGP)
• Institute of Theoretical Physics (ITP)
• Institute of Solid State Physics (IFKP)
• Institute of Soil Surveying (IFE)
• Institute for Applied Mathematics (IFAM)
• Max Planck Institute for Gravitational Physics (Albert Einstein Institute/AEI), Hannover
• Laser Centrum Hannover (LZH), Hannover
•  Gravitational wave detector GEO600, Ruthe
• Physikalisch-Technische Bundesanstalt (PTB), Braunschweig
• Center of Applied Space Technology and Microgravity (ZARM), Bremen 

The Excellence Initiative of the Federal Government

With the Excellence Initiative for Higher Education Institutions, the German Federal Government and the German states want to support research and innovation in Germany. By 2011 the Excellence Initiative will have provided funding in the amount of 1.9 billion Euros, 75% of which is contributed by the federal government, 25% of which is contributed by the states. One million Euros annually have been set aside for a total of 40 graduate schools, in the expectation that they will support the training of junior scientists. A total of 195 million Euros per year is available for networks involved in top scientific research, so-called excellence clusters. Universities that have at least one international cluster of excellence, a graduate school, and a coherent overall strategy to be globally recognized as a “beacon of science” can also apply for the funding of "future concepts for top university research.” Some 210 million Euros are available per year for this line of funding.

Background information

The goal of the scientists involved in QUEST is to unite the quantized world of quantum physics with the continuous relativity theory of space, time and gravitation into one physical model. In doing so, scientists now have recourse to completely new concepts concerning precision measurement of length, time, acceleration, rotation, etc. which have been created in recent years by new quantum technologies and quantum engineering methods. These include, for example, the new atomic lasers or the Bose-Einstein condensates, a macroscopic quantum state of matter that was predicted by Einstein and that has since been experimentally verified.

QUEST research projects seek to establish a close bond between basic and applied research, as the findings of basic research provide essential information for applications such as next generation of satellite navigation systems. These include the European navigation system Galileo, new earth observation satellites, or considerably more precise geodetic reference systems. Quantum technologies, as used and developed here, therefore form an excellent basis for industrial co-operation and innovative high-tech products.

The “quantum engineering” area

The new possibilities for the manipulation of light and matter, which are described by the term "quantum engineering," have revolutionized nuclear physics and quantum optics in recent years. A completely new range of parameter areas has therefore been opened by these fields of research: just as the coherent (connected) light waves of the laser light can also be described as a current of numerous light particles or light quanta – so does a particle stream of extremely cold atoms (cooled down to ca. -273 °C by means of laser cooling, thereby reaching a temperature near that of absolute zero) increasingly take on the character of a coherent wave of matter as the temperature drops.

So-called atomic lasers are thereby entering the realm of the conceivable. These would emit material waves with laser-like properties. This opens up an entirely new range of applications in so-called atomic optics – like the laser in optics – in quantum optics, both in fundamental research, as well as in innovative technical applications.

Quantum engineering therefore constitutes its own major research area in QUEST. This field forms the basis for other research areas and innovations in the Cluster of Excellence. These include, for example, innovative quantum sensors, the next generation of optical atomic clocks, in which the “pendulum” oscillates at the rate of the light frequency (about 1015 Hz), next-generation gravitational wave detectors and innovative precision measuring devices for geodesy.

In this sense, quantum engineering provides a workbench for new ideas to drive research in these fields, to explore its physical boundaries, and particularly to investigate new, far more complex and coupled quantum phenomena. The experimental and theoretical methods of different disciplines are brought together here to create new control mechanisms for quantum systems.

The “quantum sensors” area

Such control is the prerequisite for the development of next-generation quantum sensors. In the field of “quantum sensors” the development of new gravitational wave detectors, optical frequency standards and atomic clocks, as well as inertial sensors with light and material waves are planned.

The three currently operational gravitational wave observatories, LIGO (US), Virgo (Italian-French) and GEO600 (German-British) are the most sensitive detectors for the measurement of length differences ever created. The length change in the two arms of the detectors is measured by a high-precision laser interferometer. In GEO600, the gravitational wave detector in Ruthe, south of Hannover, the next-generation technology has already been tested and used.

To make further progress in this area, QUEST is already working intensively on new light sources that harness a special form of light - “squeezed light” - to reduce light-based noise to a level below the so-called quantum noise limit. This research area has also given rise to the necessary developments for the space-borne gravitational wave detector “LISA”, which was conceived under the scientific leadership of the Albert Einstein Institute in Hannover. Atomic optics have the potential to provide atomic clocks with the capacity for such unimaginable accuracy that they deviate measurably from one another when separated by only one centimetre in height above the laboratory table, due to the relativistic redshift in the gravitational field of the earth. This research work in QUEST gives rise to highly interesting application possibilities in geodesy, which can thereby measure the geoid (potential of the earth's gravity) precisely with the help of these extremely precise atomic clocks.

On the other hand, new atomic interferometers are being designed and built in QUEST that, as highly precise inertial sensors, will far surpass the best “classical” acceleration and rotation sensors. These sensors will be deployed in outer space to research the free fall of different masses, especially on the quantum level with various elements or isotopes, in order to investigate the so-called equivalence principle more precisely. This could provide the first clues for a theory of the yet unexplored quantum gravitation. Pursuing the same aim, QUEST is seeking to check the consistency of natural constants by comparing highly precise atomic clocks, which are each operated with different isotopes as atomic reference points.

The “space-time research” area

In the hunt for the great goal of fundamental physics, the ultimate union of quantum theory and gravitation, theorists have developed various radical concepts over the past 30 years, such as the theory of strings with its additional spatial dimensions. All the candidates for a solution predict specific novel space-time phenomena, the magnitude of which is fully unknown. Among other things, the following are expected: violations of the equivalence principle (“all masses fall at the same rate”), temporally changing “fundamental constants” (such as elementary electrical charge), fluctuations in the geometry of space-time (“space-time foam”), abnormal light propagation in space, modified gravity and a gravitational wave echo of the Big Bang.

The precision instruments to be developed in QUEST are excellently suited for probing the structure of space and time on a previously unachieved small scale, thus making it possible to trace these phenomena. In this regard QUEST is seeking to balance and interlink theory and experiments. On the one hand, the design of theoretical models influences the applications of QUEST's quantum centres through the suggestion of innovative experiments with atomic clocks, inertial sensors (for precise measurement of acceleration, rotation and inertial forces), gravitational wave detectors and, for example, lunar laser ranging. On the other hand, there is a focus on improving the precision of the efforts of theoreticians that will enable them to narrow down their models of quantum gravitation.

The special strength of QUEST consists in its unique combination of space-time probes: new quantum sensors and precision clocks can check the consistency of natural constants and support, for example, millimetre-exact earth surveying, which would revolutionize the exploration of the earth system and presents challenges for the general theory of relativity. Future gravitational wave observatories on Earth and in space would test our cosmological notions of the quantum origin of our universe, thus complementing the physics of modern particle accelerators. QUEST can only win: if no new phenomena are found, this would narrow down the number of viable theories; any clear detection of a quantum gravitation signal, on the other hand, would be a sensation!

The “innovative technologies” area

QUEST's ambitious goals are to a large extent based on highly developed experimental techniques, which are researched and expanded at the highest level in the “Innovative Technologies” Department. Based on the traditional basic research on laser physics in Hannover, it is mainly groups of the Laser Zentrum Hannover e.V., the PTB and the Institute of Quantum Optics that are working together on the development of next-generation optical technologies. In this regard, laser systems are researched and developed further, for which Hannover is the only place in the world where they are available. They are distinguished by an extremely high light output, high precision in the wavelength of the laser light or by low noise. As a result, laser systems from Hannover also form the basis of the American gravitational wave detectors.

The demanding requirements for the lasers also apply to the individual optical components that make up the systems related thereto, such as the laser mirrors or special optical fibres. The requirements for these components are becoming increasingly demanding. For example, the optics must be able to hold up while rendering extreme optical performance or, for example, be suitable for use in space, such as the laser system developed in Hannover for the upcoming Mercury mission. To make this possible, new materials and concepts are being explored for use in optical systems. QUEST enables the scientific working groups involved to further expand their worldwide leadership position, or, in other cases, to join in collaborating with the leading groups in the world.