Not exactly. M-Theory - and all that - are mathematically based. But it's easy for many to distrust a framework based on mathematics alone.
It's my sense too that angels, and the devil, do not exist outside the illustrative sense of God as they would otherwise undermine monotheism.
Though, "If I knew God I'd be Him."
Reagrdless of mathematics, I do believe in angels.
My guardian angel and the archangels.