QM calculation of vacuum energy

In summary, the conversation discusses a theory's predictions being labelled as rubbish by scientists if they are significantly different from experimental observations. However, the quantum mechanical calculation of vacuum energy, which has a discrepancy of 120 orders of magnitude with the Casimir effect, is not being labelled as rubbish. This is because there is agreement between theory and experiment for the Casimir effect and the discrepancy can be explained by the assumptions and simplifications made in the calculations. Some believe that a new quantum theory is needed to explain this discrepancy.
  • #1
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If I came up with a theory that had predictions 100 times larger or smaller than experimental observation my theory would labelled rubbish by scientists.The quantum mechanical calcualtion of vacuum energy is 120 zeros at odds with experimental observation ( casimir effect).Why aren't people labelling quantum mechanics as rubbish?
 
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  • #2
battery said:
If I came up with a theory that had predictions 100 times larger or smaller than experimental observation my theory would labelled rubbish by scientists.The quantum mechanical calcualtion of vacuum energy is 120 zeros at odds with experimental observation ( casimir effect).Why aren't people labelling quantum mechanics as rubbish?

If that's all your theory can predict, then yes, it is totally rubbish. But if your theory predicts other things that actually WORK, and you are using the very effect of that theory right this very second, then how can it be labelled as rubbish?

And it isn't widely accepted that such vacuum energy has THAT high of an energy density. There are fringe physics and crackpots that may think so, but we have seen from experiments on casimir effect that such an effect is extremely small and extremely difficult to detect, and that IS within what QM has predicted as well! I can show you MANY other nonsensical effects using many-body quantum mechanics. Does this make QM rubbish? No. You have to know that extrapolating QM in such a way requires significant assumptions and simplifications (example: mean field approximation). It is such simplification that can easily be at fault. Full, real phenomena are very seldom solved without making such assumptions.

Zz.
 
  • #3
battery said:
The quantum mechanical calcualtion of vacuum energy is 120 zeros at odds with experimental observation ( casimir effect).Why aren't people labelling quantum mechanics as rubbish?

As ZapperZ has already said, there is agreement between theory and experiment for the Casimir effect.

Do you mean the difference between vacuum energy and observed cosmological dark energy? In this case, rough calculations, as given in, e.g., Carroll's general relativity book, lead to a discrepancy between "theory and experiment" of 120 orders of magnitude. Other calculations give different results, but usually there is a large discrepancy.

Many people think that an accepted quantum theory that can be used for calculations is needed to explain this.

A minority, e.g. Roger Penrose, think that a large change in quantum mechanics is needed.
 
  • #4
I don't really think this discrepancy is so weird. Remember that the construction of quantum field theories starts with the assumption that space-time is Minkowski space. This means that we're describing a universe where there is no gravity. The theories we construct in this way are in excellent agreement with experiments about everything, except this one thing that has no relevance whatsoever in a world without gravity.
 

1. What is vacuum energy in the context of quantum mechanics?

Vacuum energy, also known as zero-point energy, is the lowest possible energy that a quantum mechanical physical system may have. It is the energy of the vacuum state, which is the lowest energy state of a quantum field theory. It is a fundamental concept in quantum mechanics and plays a role in various phenomena such as the Casimir effect and the Lamb shift.

2. How is vacuum energy calculated in quantum mechanics?

In quantum mechanics, vacuum energy is calculated using the Heisenberg uncertainty principle. This principle states that there is a minimum amount of energy associated with any physical system, even in its lowest energy state. This minimum energy is known as the zero-point energy and is calculated by summing up the energy of all possible quantum states of the system.

3. Why is vacuum energy important in quantum mechanics?

Vacuum energy is important in quantum mechanics because it has a direct impact on the behavior of particles and fields in the vacuum state. It affects the stability of atoms, the behavior of particles in the vacuum, and the creation and annihilation of particles in a vacuum. It also plays a role in the understanding of the universe at a fundamental level.

4. What are some applications of vacuum energy in quantum mechanics?

Vacuum energy has various applications in quantum mechanics. It is used to explain the stability of atoms and the Lamb shift, which is the small energy shift in atomic spectral lines due to the interaction between the electron and the vacuum state. It also plays a role in the prediction of the Casimir effect, which is the force between two parallel plates in a vacuum due to the zero-point energy of the quantum fields between them.

5. Can vacuum energy be measured in quantum mechanics?

Although vacuum energy cannot be directly measured in quantum mechanics, its effects can be observed and measured through various phenomena such as the Casimir effect and the Lamb shift. However, the actual value of vacuum energy remains a theoretical concept and is a subject of ongoing research and debate in the field of quantum mechanics.

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