Joint project with Goethe University Frankfurt and Technische Universität Darmstadt

The German Research Foundation (DFG) has approved a new Transregio Collaborative Research Centre (CRC-TRR) in which physicists from Goethe University Frankfurt, Bielefeld University, and Technische Universität Darmstadt will be carrying out research on ‘strongly interacting matter under extreme conditions’. Over the next four years, the DFG will be funding the CRC-TRR with about 8 million Euros. Professor Dr. Dirk Rischke from Frankfurt University is the Speaker; Professor Dr. Frithjof Karsch from Bielefeld University his deputy.

In this context, ‘extreme conditions’ means high temperatures and densities such as those present during the first millionth of a second after the Big Bang: several billion degrees Celsius (i.e. one hundred thousand times hotter than the core of our sun) and multiples of the density attained in atomic nuclei (several hundred million tons per cubic centimetre). Under these conditions, matter is dominated by what physicists call strong interaction. This is one of the four fundamental forces in physics. It is responsible for binding protons and neutrons to form atomic nuclei and for their internal structure composed of quarks and gluons. Under extreme conditions, strongly interacting matter forms new states comparable with the different aggregate states of water as ice, liquid, and gas. Whereas these are being studied experimentally in large-scale particle accelerators such as the Large Hadron Collider (LHC) at CERN in Geneva – and in future, at the Facility for Antiproton and Ion Research (FAIR) in Darmstadt – the new CRC-TRR will cast light on the topic from a theoretical perspective.

Fourteen subprojects should study the fundamental properties of strongly interacting matter and apply them to the physics of the early universe  and to experiments on heavy ions. The stated aim is to proceed as directly as possible from the fundamental theory of strong interaction known as quantum chromodynamics (QCD). This theory is more than forty years old, and research on it has already resulted in several Nobel Prizes. Nonetheless, it has frequently proved difficult to make concrete predictions within a QCD framework. In particular, it has not yet been possible to use QCD to derive a satisfactory explanation of the properties of macroscopic concentrations of strongly interacting particles at high temperatures and densities.

What is unique about the new CRC-TRR in this context is the combination of complex numerical simulations on high-performance supercomputers (‘lattice QCD’) with analytically based methods. ‘This involves a close cooperation so that we can optimally exploit the strengths of each approach along with the differences in expertise at the three research locations,’ emphasizes the Speaker of the CRC-TRR, Prof. Dirk Rischke from Goethe University Frankfurt. Prof. Jochen Wambach from the Technische Universität Darmstadt – Rischke’s deputy together with Prof. Frithjof Karsch from Bielefeld University – adds: ‘Many of us already know each other for a long time and have also worked together successfully in the past. However, the Transregio raises this cooperation to a completely new level.’

The cooperation on equal terms between the three partner universities is underlined by the fact that it has already been agreed to rotate the post of Speaker of the CRC-TRR at the beginning of each successfully approved new funding period. ‘The complex theoretical questions along with the experiments that are either being performed currently or are already planned in this extremely active field of research – both nationally and internationally – will deliver ideas for a wide range of research projects over the coming decade,’ says Karsch. Rischke, Karsch, and Wambach all agree that ‘this makes us confident that we shall be able to fill up the maximum funding period for a CRC with interesting projects.’