A novel model that employs quantum correction terms to
extend Einstein's theory of general relativity suggests that the universe may
have lived forever. The model might simultaneously address several issues by
taking into consideration dark matter and dark energy.
According to general relativity, the universe is 13.8
billion years old, which is the generally accepted age. All of existence is
believed to have originated in a single, singularity-like point that was
infinitely dense. The universe didn't actually start until this point started
to expand in a "Big Bang."
Although the equations of general relativity directly and
ineluctably lead to the Big Bang singularity, some scientists find this to be
problematic because the math can only explain what occurred immediately after
the singularity—not at or before it.
"Because the laws of physics seem to be violated there, Ahmed
Farag Ali of Benha University and the Zewail City of Science and Technology in
Egypt told Phys.org that the Big Bang singularity is the most significant issue
with general relativity."
In an article that was recently published in Physics Letters B, Ali and coauthor Saurya Das from the University of Lethbridge in Alberta, Canada, demonstrated how their novel theory—in which the cosmos has no origin and no end—can resolve the Big Bang singularity.
The physicists stress that they do not arbitrarily apply their quantum correction terms to try to specifically get rid of the Big Bang singularity. Their work is based on concepts put out by David Bohm, a theoretical physicist also noted for his contributions to physics philosophy. Beginning in the 1950s, Bohm investigated using quantum trajectories in place of conventional geodesics (the shortest route between two locations on a curved surface).
In their study, physicists Ali and Das Das applied these
Bohmian trajectories to an equation created at Presidency University in
Kolkata, India, in the 1950s by physicist Amal Kumar Raychaudhuri. When Das
attended that university as an undergraduate student in the 1990s, Raychaudhuri
was also his professor.
The quantum-corrected Friedmann equations, which describe
the expansion and evolution of the universe (including the Big Bang) within the
setting of general relativity, were developed by Ali and Das using the
quantum-corrected Raychaudhuri equation. The model incorporates aspects of both
quantum theory and general relativity, despite not being a true theory of
quantum gravity. In addition, Ali and Das anticipate that their findings will
hold true whether or not a complete theory of quantum gravity is developed.
No strange or dark things
The new model does not predict a "huge crunch"
singularity in addition to not forecasting a Big Bang singularity. According to
general relativity, the cosmos might begin to contract before collapsing
massively in on itself to form an impossibly dense point once more.
In their study, Ali and Das describe how a crucial
distinction between Bohmian trajectories and classical geodesics allows their
model to avoid singularities. Singularities are the places where classical
geodesics finally converge and cross each other. Singularities do not arise in
the equations because Bohmian trajectories do not intersect one another.
The researchers clarify that the quantum corrections can be viewed as a radiation term and a cosmological constant term (without the necessity for dark energy). These conditions maintain the universe's limited size, giving it an infinite age. Additionally, the terms provide predictions that nearly match the cosmological constant and cosmic density as observed today.
New gravitational particle
The model states that there is a quantum fluid at the centre
of the universe. Theoretical massless particles called gravitons, which mediate
the gravitational force, are thought to make up this fluid, according to the
scientists. The existence of gravitons is regarded to be crucial to a quantum
gravity theory.
Further support for this model has been provided in a
companion study by Das and another colleague, Rajat Bhaduri of McMaster
University in Canada. They demonstrate that gravitons can create the
Bose-Einstein condensate, which bears the names of both Einstein and
Satyendranath Bose, a physicist from India.
The physicists intend to conduct a more thorough analysis of
their concept in the future since it has the potential to explain dark matter
and dark energy as well as the singularity that results from the Big Bang.
Small inhomogeneous and anisotropic perturbations will be taken into
consideration when they perform their analysis in the future, but they do not
anticipate that these perturbations will have a large impact on the outcomes.
"It is gratifying to see that such simple fixes have the
ability to address so many problems at once, Das added."
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