By Sourendu Gupta, Rajiv Gavai, Nilmani Mathur and Saumen Datta
One of the enduring problems in physics is to understand how the universe evolved from a single point after the Big Bang. Scientists across the world have been trying to recreate the conditions that might have existed in the immediate aftermath of the Big Bang. What happened in those first few microseconds are crucial in understanding how the nature works.
It was in those first few microseconds, that matter as we know it, was created. For a long time, atoms were considered to be the most fundamental particle of matter. But soon, the atom was “split” and the world of protons, neutrons and electrons was revealed. We now know that even protons and neutrons, which are found in the nucleus of atoms, are not the elementary particles. They are composed of quarks and gluons.
But it is impossible to create quarks and gluons at normal temperatures. They can be seen only under very special conditions. They came into existence immediately after the Big Bang, as did the other fundamental particles. The quarks and gluons quickly coalesced to form the protons and neutrons within a few microseconds.
One of our groups is now trying to figure out the conditions under which this “coalescence” becomes a “phase transition”— the change from quark matter to nuclear matter. More specifically, we have been trying to estimate the temperature and density of quark matter at which this phase transition begins to happen. Another group of ours is engaged in finding the detailed properties of particles like protons and neutrons.
Our research is purely theoretical. Using quantum field theory, mathematical tools and heavy computing, we have tried to estimate the transition temperature and density. Such attempts have been made earlier as well, but those estimates have not been satisfactory.
I along with my colleague Rajiv Gavai, were able to develop a new method to make these calculations. The estimations involve long and very complex calculations and even supercomputers take years to process the results.
Based on our results, we have estimated that the temperature at which this interesting phase transition — the singular evolution of quark matter into nuclear matter — would take place will be nearly two trillion Celsius, while the density of quark matter would have been many times of what exists in the collapsing neutron stars.
Our calculations are presently in the process of being verified through experimental data by the Relativistic Heavy Ion Collider (RHIC) at the Brookhaven National Laboratory in the United States. In collider experiments like these, sub-atomic particles are accelerated to very high speeds, comparable to that of light, in opposite directions and are allowed to collide with each other. The energy released in these collisions raises the temperature of nuclear matter, creating conditions similar to that experienced immediately after the Big Bang. Collider experiments are being carried out at several places. The most famous of these is the Large Hadron Collider at the European CERN facility on the France-Switzerland border.
Preliminary results from the RHIC have been very interesting and seem similar to our theoretical proposals. The final results will take more time to come out. In the meanwhile, we are calibrating and extending our calculations further. We are planning to use a new and more powerful supercomputer, which is currently the 114th most powerful in the world and will give us a better understanding of the system.
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