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somy
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Can anyone explain the relation between quantum field theory and relativity.
I mean the "cosmological constant".
Tanks a lot.
I mean the "cosmological constant".
Tanks a lot.
somy said:Can anyone explain the relation between quantum field theory and relativity...
From the perspective of general relativity it is known that at cosmological scales spacetime can be approximated in a good accuracy with the expanding Robertson-Walker metric. A Quantum Field Theory can be indeed defined on this expanding background.marcus said:Space, in GR, has a dynamic unpredetermined geometry which is constantly be influenced by the flow of matter.
One special solution of the GR equation is the static flat solution you get when the universe is perfectly empty----this is Minkowski space and it was the space of the earlier (1905) theory of special rel.
Quantum field theory has been constructed on Minkowski space.
QFT and GR do not even share the same space, which is one reason for the disconnect.
One widely used test of whether a theory is compatible with GR is
to see whether it is "background independent"-----that it does not rely on a prior rigid geometrical framework (like Minkowski space) but can be defined without precommitting to a background geometry.
What is called "relativistic quantum field theory" is not, in fact, background independent and is therefore not relativistic in the GR sense.
somy said:Can anyone explain the relation between quantum field theory and relativity.
I mean the "cosmological constant".
Tanks a lot.
Chronos said:I think there is something fundamentally wrong with QT predictions of ZPF energy density. Unless GR is horribly flawed, which is not evident, QT appears more suspect at this point. While QT has been enjoyed some huge successes, it has also demonstrated some profound deficiencies - notably that certain particles that should have appeared at certain energy levels, have not, and cutoff energy limits predicted have been grossly violated.
The Cosmological Constant is a term in Einstein's equations of General Relativity that represents the energy density of the vacuum of space. It is important in Relativity and Quantum Field Theory because it helps explain the expansion of the universe and the distribution of matter in space.
The Cosmological Constant acts as a repulsive force in Einstein's equations, pushing galaxies away from each other and contributing to the overall expansion of the universe. It is believed to be responsible for the accelerated expansion of the universe that was discovered in the late 1990s.
Quantum Field Theory is a theoretical framework that combines the principles of Quantum Mechanics and Special Relativity. It is used to study the behavior of particles and fields at the smallest scales, and it is essential in understanding the Cosmological Constant as it allows us to calculate the energy density of the vacuum and its effects on the universe.
The Cosmological Constant is often equated with Dark Energy, as it is believed to be the source of the mysterious force that is causing the accelerated expansion of the universe. However, it is important to note that the Cosmological Constant is just one possible explanation for Dark Energy, and its origin is still not fully understood.
In Einstein's equations, the Cosmological Constant is represented by a constant value. However, there are theories that suggest it may change over time due to the nature of Quantum Mechanics. This is still a topic of ongoing research and debate among physicists.