QUEST Excellence Cluster gets underway

Research on the quantum limit begins

Today, on 23 May 2008, the Hannover QUEST Excellence Cluster (Center for Quantum Engineering and Space-Time Research), has officially started its work. In the four areas of quantum engineering, quantum sensors, space-time research and novel technologies, around 60 new scientists will be involved in the coming five years, in addition to the 190 already pursuing research on the quantum limit.

They will further refine already available quantum technologies, in order, for example, to

• answer fundamental questions of physics - including those concerning the structure and the fundamental forces of our universe.
• undertake application-oriented work and develop new knowledge, e.g. for next-generation satellite navigation systems or earth observation systems.

QUEST is, in the broadest sense, an interdisciplinary quantum workshop.

To this purpose, QUEST has created a new infrastructure and new work groups that strategically expand the existing research competence of the Institutes. For example, eight new professorships and more than ten junior research groups and other research groups will be established at Leibniz Universität Hannover and its partners by QUEST this year. 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.

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.

“The Excellence Initiative has generated a tremendously positive impetus throughout the Lower Saxony community of higher education institutions. These institutions, which prevailed in three lines of funding among more than 300 applications, are among the top higher education institutions in Germany. The approval of the QUEST Excellence Cluster “Center for Quantum Engineering and Space Time Research” is a great distinction for the Department of Physics, as well as for the Leibniz Universität Hannover as a whole and we heartily congratulate all of those involved," said Minister of Science Lutz Stratmann.

Prof. Dr. Wolfgang Ertmer, Coordinator of QUEST: “We have leading facilities in Hannover for carrying out research on individual atoms, atomic interferometers, atomic quantum sensors, lasers and atomic clocks, as well as facilities for astronomy with gravitational waves or for the observation of the earth and geodesy. The intensive cooperation between such diverse fields will decisively contribute to the resolution of many scientific issues.”

Prof. Dr. Karsten Danzmann, Deputy Coordinator of QUEST: "The launch of QUEST is a very special moment for all of those involved, whose outstanding commitment is now being rewarded with excellent interdisciplinary research conditions. QUEST comes up well when compared to other internationally renowned scientific institutions."

Scientific institutions taking part in QUEST:

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

The Excellence Initiative of the German 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. 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”. 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.

Area “quantum engineering”

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 thereby been opened up 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 thereby enter the realm of the conceivable. These would emit material waves with laser-like properties. This opens 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 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 hammering out new ideas for driving 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 Hanover, 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 use 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 used 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 technologies, which are researched and expanded at the highest level in the “New 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.