June 17, 2024

Black holes precipitate as dark matter

Percentage of matter in the universe Ordinary matter makes up just over four percent of the contents of our universe. The majority (about 72 percent) appears to be made up of dark energy.

In order to estimate the number of primordial black holes, only theoretical calculations remain. As experts have discovered, the range could be very large: constraints imposed by cosmic background radiation, which requires the universe to be homogeneous 300,000 years after the Big Bang. It allowed strong fluctuations in density a few moments after the Big Bang -And with it a large number of primordial black holes.

Very strong approximation

Models from the field of quantum field theory were used for these calculations. This is a physical system that allows us to describe the behavior of matter in the subatomic system. This is exactly what was needed to describe the universe at a time when quarks, gluons and other elementary particles were compressed into a very small space. Quantum field theory has been very well tested, but it has a serious weakness: the calculations are so complex that it is almost impossible to calculate the result accurately. You always have to rely on approximation methods, which also turn out to be very computationally intensive.

Until now, researchers have used a very rough estimate to estimate the number of primordial black holes: it was as if we were calculating the sine function sin(s) through a straight line s An approximation (in a small area around zero this may be sufficient, but once you move away from zero, this approximation is clearly wrong). Christian and Yokoyama realized that this simplification could be too powerful Already feared in previous work. Now they can prove that their suspicions were justified.

Taylor Series | The simplest way to deal with a complex function is Taylor’s method, which is based on perturbation theory used in physics. This allows functions such as sine (black) to be approximated. The more terms you take into account (red: one, orange: two, yellow: three and so on), the better the approach represents the entire solution.

Using a slightly better approximation, the two physicists were able to show that the possible number of primordial black holes is decreasing dramatically. Christian and Yokoyama included additional terms in the original approximation: It’s as if one were sin(s) during s + s3/3 (which actually gives slightly better results). With their more precise model, Christian and Yokoyama were able to see that very large fluctuations in density – which would be necessary for a large number of primordial black holes – are out of proportion to the cosmic background radiation we observe today. Thus, the two physicists concluded that the number of primordial black holes is much smaller than previously assumed.

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