Physicists have modeled the formation of a quark-gluon plasma in the collisions of neutron stars. It turned out that it is accompanied by a characteristic increase in the frequency emitted by the system of gravitational waves, which can measure the existing detectors. The simulation results will help to detect the quark-gluon plasma in vivo, write the scientists in the journal Physical Review Letters.
The quark-gluon plasma (or homoplasy) is the state of matter in which matter moves at very high temperatures. The mechanism of occurrence is largely similar to a conventional plasma. Formation of the latter is due to ionization — the separation of nuclei and electrons in atoms. The substance as a whole remains electrically neutral, but its individual parts acquire an electric charge.
At the birth of the quark-gluon plasma are destroyed is not the atoms and hadrons — smaller particles, which consist of three quarksthat exchange gluons. Quarks carry color charge (the so-called quantum characteristics), whereas hadrons — neutral with respect to this charge. Colorless in General, the quark-gluon plasma is, thus, of the colored particles.
Now according to the accepted theory, the universe was a state of quark-gluon plasma in the range 10-11 — 10-6 seconds after the Big Bang. The researchers associated with the properties this form of matter baryon asymmetry of the predominance of matter over antimatter, which allowed the particles to escape annihilation and become a galaxy.
Today, physicists have learned short-term (a billionth of a second) to quark-gluon plasma by colliding particles in accelerators, however, available energy is often not enough to obtain reliable results. The problem could allow the detection of CSB in natural conditions — it is assumed, in particular, that it occurs in the collisions of neutron stars. Observations that would confirm a hypothesis are not currently available.
Scientists from the University of Frankfurt Goethe under the direction of Lucas of Weyhe (Lukas R. Weih) decided to explore the gravitational signal, which is emitted at the birth of the quark-gluon plasma in such collisions. The authors appealed to the equation of state of nuclear matter (managed to get it on the basis of experimental data). Using this equation, physicists have simulated the merger of neutron stars with different parameters. The researchers observed the frequency of the emitted gravitational waves and the density in the center of the resulting object. This last value allows to detect the transition of a substance into a state of quark-gluon plasma.
In the result, the physicists have revealed the most favorable for the detection of the quark-gluon plasma scenario. It hypermassive star goes into a metastable state by avoiding collapse. The quark-gluon plasma is not formed at the moment of collision, but with a delay of the order of several milliseconds. Such a process corresponds to a characteristic gravitational signal, whose frequency after the merger of stars first increases, and then stabiliziruemost. If the radiation is of such form will be able to observe experimentally, that confirms the existence of the quark-gluon plasma in terms of the Universe of late and will seriously expand the opportunities for its study.
Earlier we wrote about how traces of the quark-gluon plasma found in collisions of protons and with the assist of gravitational interferometers want to catch particles of dark matter.