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The Big Bang
Published in Teunis C. Dorlas, Statistical Mechanics, 2021
The average density of visible matter in the Universe is estimated to be ρmat≈10−30g cm−3. Inserting this into equation (16.2), we find that k<0 so that the Universe would be infinite in extent and forever expanding. However, it is now thought that there is a large amount of invisible matter, so called ‘dark matter’ present in the Universe which could turn this conclusion around. On the other hand the cosmological constant is also thought be non-zero and as a result the Universe might still be expanding indefinitely.
Essentials of Data Analytics
Published in Adedeji B. Badiru, Data Analytics, 2020
Einstein’s elegant equation published in 1916 is the foundation for his theory of gravity, the theory of general relativity. The equation relates the geometrical curvature of space-time to the energy density of matter. The theory constructs an entirely new picture of space and time, out of which gravity emerges in the form of geometry and from which Newton’s theory of gravity emerges as a limiting case. Einstein’s field equation explains many features of modern cosmology, including the expansion of the universe and the bending of star light by matter, and it predicts black holes and gravitational waves. He introduced a cosmological constant in the equation, which he called his greatest blunder, but that quantity may be needed if, as recent observations suggest, the expansion of the universe is accelerating. A remaining challenge for physicists in the 21st century is to produce a fundamental theory uniting gravitation and quantum mechanics.
Gut and Cosmology
Published in K Grotz, H V Klapdor, S S Wilson, The Weak Interaction in Nuclear, Particle and Astrophysics, 2020
K Grotz, H V Klapdor, S S Wilson
The cosmological problems discussed in Section 9.2, which arise in connection with the standard model, may be at least partially resolved if the universe went through an inflationary epoch in the course of its early development (Guth (1981), Linde (1982, 1984), Albrecht and Steinhardt (1982)). To understand the meaning of this, we consider the Friedmann-Einstein-Lemaitre equations (9.10) and (9.11). The case previously considered, Λ = 0, corresponds to the assumption that the vacuum does not contribute to the energy density of the universe. This seems self-evident in classical physics. However in quantum field theory, the vacuum already contains different quantum fields. These are found in a state of least energy which is, however, not necessarily zero. Thus we assume in the following that we may attribute a non-vanishing energy density ρV to the vacuum. In modern quantum field theory, the cosmological constant Λ of general relativity is interpreted as the energy density of the vacuum. The relationship between the two quantities is (McCrea (1951), Zeldovich (1968)) () Λ=8πGNρV
Probability, Choice, and Reason
Published in Technometrics, 2022
Chapter 5 “Probability, Truth, and Reason” explores some mind-bending ideas which could be testable or falsifiable. It includes C.G. Hempel’s paradox, aka the Raven paradox, due to which if something might or might not exist, and is not observed, it is more likely to exist if it is less observable than something else which is more observable; the Simulated World question on the probability that we live in a virtual reality created by an advanced civilization; the Quantum World thought experiments on the famous E. Schrödinger’s Cat simultaneously existing in different states of the life and death, with the related “quantum suicide” experiment about the alternative realities, or the “many-worlds interpretation” (MWI); the Fine-Tuned Universe puzzle, which discusses the perception and concepts of the cosmological constant and the universe expansion, dark energy existence and symmetry-asymmetry paradox, initial conditions for the Big Bang and alien civilizations; and William Occam’s Razor principle of simplicity, or parsimony in choice of theories with the fewest assumptions, which corresponds to escaping overfit in statistical estimations (also minted by Einstein—“Everything should be as simple as it can be, but not simpler”—S.L.).
Molecular theory of the genetic code
Published in Molecular Physics, 2018
The appearance of irreducible matrix blocks is usually a problem, which one wants avoid, but here it becomes a blessing in disguise. In addition to the possibility to map a CDS or a CDE onto a Jordan block, displaying the information bearing transformation , one can show that the appearing multi-curve-crossing structures prohibit decoherence, commensurate with its thermal structure, providing a self-referential formulation of some basic properties of general relativity, like a simple derivation of the Schwarzschild line element, evading the cosmological constant, establishing background independence and black hole-like objects. The self-referential characteristic exhibits a surprising relation to Gödel’s incompleteness theorems [19,29,30] via a conversion of an extended logical negation table to a linear algebra vernacular. All in all, it arranges for fundamental quantum theory to be applicable from the microscopic domain to the macroscopic and cosmological ranks, including teleonomic structures in biological complex enough systems.