Is Negative Mass Possible in String Theory Through Quantum Fluctuations?

[Strange_matter]

If dark energy is caused by quantum fluctuations, where does this energy come from? Also according to string theory mass is determined by the sum of a string's positive, vibrational energy and its negative energy from quantum fluctuations. Could it be possible to create a particle with negative mass by creating a string with more energy from quantum fluctuations, than vibrational energy?

 

[UltrafastPED]

If it is caused by quantum fluctuations ... then it doesn't come from anywhere, and simply comes and goes.

Your further suppositions don't seem to be well founded.