Inflationary Energy: Origins & Conversion

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In summary, the conversation discusses the origin of energy in the universe, specifically the energy of the inflation field. It is stated that when inflation ends, the energy of the inflation field converts into a "hot soup" of particles. The source of this energy is not fully understood and there are conflicting theories, such as it arising from quantum fluctuations or from the creation of spacetime itself. It is also mentioned that pressure is a contributor to the gravitational field but cannot exist without matter or energy. The main mystery lies in the origin of the inflaton particle and its nearly-uniform density. Overall, the concept of energy conservation in an expanding universe is a complex and ongoing topic of discussion.
  • #1
windy miller
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As I understand it when inflation ends, it gives up the energy of the inflation field and converts into a "hot soup" of particles.
But where does the energy of the inflation field come from? Can it borrow it from the gravitational field ?
 
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  • #3
You get pair production at a furious pace at the end of inflation from the energy of the inflaton field. Where the inflaton energy originates is an unsolved mystery. A common hypothesis is it arises due to quantum fluctuations in the vacuum energy density of the infant universe - IOW it arises from nothing. A lot of people find that unsatifying because you need space and time as a backround for vacuum energy to exist. If spacetime itself was created by the BB, no space or time existed prior to the BB - turning the whole vacuum fluctuation thing into a chicken and egg paradox. Bear in mind there is no gravitational field without matter or energy. Welcome to the conflicting world where quantum physics meets theoretical cosmology.
 
  • #4
Isn't pressure a contributor to the gravitational field ?
 
  • #5
windy miller said:
Isn't pressure a contributor to the gravitational field ?

Pressure appears in the stress-energy tensor, so it is part of the source of the gravitational field. But you can't have pressure without having matter or energy.
 
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  • #6
Chronos said:
Where the inflaton energy originates is an unsolved mystery.
I don't think this is an accurate statement. Where the inflaton energy originates isn't a mystery at all: it doesn't originate from anywhere as energy isn't conserved in an expanding universe. In particular, the properties of inflation make it so that a small amount of initial energy gives rise to a huge amount of energy at a similar density spread across a much larger region of space. There's no real mystery as to how this occurs: inflation has a nearly-constant energy density, which leads to a nearly-exponential expansion rate, which leads to a nearly-exponential increase in energy.

The mystery is where the inflaton itself came from: what is the inflaton particle, and how did it come to have a nearly-uniform density over a small region of space?

Also note that there are other alternative explanations for the early universe besides inflation, and those give rise to somewhat different questions about how our universe got its start. The answer to the energy issue remains the same in all of these models, however: energy isn't conserved in an expanding universe.
 
  • #7
I'm guessing the origins of energy in the universe is more a mystery than its subsequent conservation, or lack thereof.
 

1. What is inflationary energy?

Inflationary energy is a hypothetical form of energy that is believed to have existed during the early universe and is thought to have caused a rapid expansion of space. It is a key concept in the theory of cosmic inflation, which attempts to explain the observed homogeneity and flatness of the universe on large scales.

2. What are the origins of inflationary energy?

The origins of inflationary energy are not fully understood, but it is believed to have been present in the universe at the time of the Big Bang. It may have originated from the decay of a scalar field, which is a type of particle that can have a non-zero energy even at the lowest energy state. Another theory suggests that it may have been a result of phase transitions in the early universe.

3. How does inflationary energy contribute to the expansion of the universe?

Inflationary energy is thought to have caused a rapid expansion of the universe in its early stages. This expansion, known as cosmic inflation, is believed to have occurred at a much faster rate than the expansion we observe today. This rapid expansion is thought to have smoothed out any irregularities and created the uniformity that we see in the universe today.

4. Can inflationary energy be converted into other forms of energy?

Yes, according to the theory of cosmic inflation, inflationary energy can be converted into other forms of energy. As the universe expanded and cooled, the inflationary energy is thought to have decayed into other forms of energy, such as matter and radiation. This process is known as reheating and is an important step in the early evolution of the universe.

5. What evidence supports the existence of inflationary energy?

There is currently no direct evidence for the existence of inflationary energy. However, the theory of cosmic inflation has been successful in explaining several key observations, such as the uniformity of the cosmic microwave background radiation and the large-scale structure of the universe. Further evidence may be found through observations of gravitational waves or future experiments aimed at detecting primordial gravitational waves.

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