# Has a calculation of the vacuum energy density been done with strings?

JandeWandelaar
TL;DR Summary
The vacuum energy density of the vacuum, as calculated in standard QFT, shows a discrepancy of about $10^{120}$ with what we see. Has the value been calculated in string theory, which doesn't assume point-like particles?
The calculation of the vacuum energy density gives us a discrepancy with reality. There should be a mass equivalent of about $10^{96}$ kilograms. I'm wondering if the assumed point-like "structure" of particles could be the cause of this wrong value.

Since string theory doesn't assume a point-like structure, I asked myself if a calculation of the energy density with strings has been done.

Delta2

Staff Emeritus
The calculation of the vacuum energy density gives us a discrepancy with reality.

Nonsense. There is no such calculation. At best, there is an estimate, and not a very good one at that.

Starting threads by presenting incorrect statements as facts is, in general, not a good plan.

JandeWandelaar
Why does the estimate differ so much with what we see? Is there an estimate in string theory? I could not find it. Only estimates in standard QFT.

Delta2
JandeWandelaar
Nonsense. There is no such calculation. At best, there is an estimate, and not a very good one at that.

Starting threads by presenting incorrect statements as facts is, in general, not a good plan.
BTW, do you know why the LaTex doesn't function? Is $10^{120}$ not right?

Homework Helper
Gold Member
BTW, do you know why the LaTex doesn't function? Is $10^{120}$ not right?
you got to put double \$ at start and end. And then refresh the page.

JandeWandelaar
Homework Helper
Gold Member
2022 Award
JandeWandelaar and Delta2
JandeWandelaar
Thanks dude (am I allowed...?). 😉

Delta2
Homework Helper
Gold Member
Is this about the so called, ground state energy of the fields?

Mentor
Why does the estimate differ so much with what we see?
Nobody knows. This is an open area of research.

Is there an estimate in string theory? I could not find it.
I'm not aware of one either.

JandeWandelaar
Nobody knows. This is an open area of research.

I'm not aware of one either.
Somehow I think $$10^{120}$$ and the cube of the Planck length, $$10^{-115}$$, are related.

malawi_glenn, PeroK and Motore
Mentor
Somehow I think $$10^{120}$$ and the cube of the Planck length, $$10^{-115}$$, are related.
Personal speculation of this kind is off limits here.

Mentor