Quantum cosmology
[501.04899Quantum cosmology: a review">][412.4362Loop Quantum Gravity">] is the attempt in
theoretical physics
Theoretical physics is a branch of physics that employs mathematical models and abstractions of physical objects and systems to rationalize, explain, and predict List of natural phenomena, natural phenomena. This is in contrast to experimental p ...
to develop a
quantum theory of the
universe
The universe is all of space and time and their contents. It comprises all of existence, any fundamental interaction, physical process and physical constant, and therefore all forms of matter and energy, and the structures they form, from s ...
. This approach attempts to answer open questions of classical
physical cosmology
Physical cosmology is a branch of cosmology concerned with the study of cosmological models. A cosmological model, or simply cosmology, provides a description of the largest-scale structures and dynamics of the universe and allows study of fu ...
, particularly those related to the first phases of the universe.
Classical cosmology is based on
Albert Einstein
Albert Einstein (14 March 187918 April 1955) was a German-born theoretical physicist who is best known for developing the theory of relativity. Einstein also made important contributions to quantum mechanics. His mass–energy equivalence f ...
's
general theory of relativity (GTR or simply GR) which describes the evolution of the universe very well, as long as you do not approach the
Big Bang
The Big Bang is a physical theory that describes how the universe expanded from an initial state of high density and temperature. Various cosmological models based on the Big Bang concept explain a broad range of phenomena, including th ...
. It is the
gravitational singularity and the
Planck time where relativity theory fails to provide what must be demanded of a final theory of space and time. Therefore, a theory is needed that integrates relativity theory and quantum theory. Such an approach is attempted for instance with
loop quantum cosmology,
loop quantum gravity,
string theory and
causal set theory.
In quantum cosmology, the universe is treated as a
wave function
In quantum physics, a wave function (or wavefunction) is a mathematical description of the quantum state of an isolated quantum system. The most common symbols for a wave function are the Greek letters and (lower-case and capital psi (letter) ...
instead of classical
spacetime
In physics, spacetime, also called the space-time continuum, is a mathematical model that fuses the three dimensions of space and the one dimension of time into a single four-dimensional continuum. Spacetime diagrams are useful in visualiz ...
.
See also
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String cosmology
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Brane cosmology
*
Loop quantum cosmology
*
Top-down cosmology
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Non-standard cosmology
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Loop quantum gravity
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Canonical quantum gravity
*
Dark energy
In physical cosmology and astronomy, dark energy is a proposed form of energy that affects the universe on the largest scales. Its primary effect is to drive the accelerating expansion of the universe. It also slows the rate of structure format ...
*
Minisuperspace
*
Hamilton–Jacobi–Einstein equation
*
Theory of everything
A theory of everything (TOE), final theory, ultimate theory, unified field theory, or master theory is a hypothetical singular, all-encompassing, coherent theoretical physics, theoretical framework of physics that fully explains and links togeth ...
*
World crystal
*
Quantum vacuum state
*
False vacuum
*
Why is there anything at all?#Something may exist necessarily
References
*
Notes
External links
Quantum Cosmology by Paulo Vargas MonizLectures on Quantum Cosmology by J.J. Halliwell
{{Quantum mechanics topics
Quantum gravity
Physical cosmology