- #1
m_brain
I just read a book by Davies and Brown entitled
"_Superstrings:_A_Theory_of_Everything_?"
They dismiss 11D theory as having a fatal flaw: -"A distinctive element
of the weak interaction is that it breaks left-right mirror symmetry.
This implies that elementary particles must be endowed with a definite
handedness, or 'chirality'...It turns out that definite chirality only
exists in spaces with an odd number of dimensions. This means that
space must have an odd number of dimensions, and hence spacetime must
have an even number of dimensions, otherwise there would be no
chirality in the laws of nature. In short, eleven spacetime dimensions
won't work."-
Any thoughts?
[Moderator's note: While it's true that M-theory on smooth spaces gives
left-right symmetric physics, M-theory compactified on singular spaces
generically leads to asymmetric, chiral theories. This is why M-theory
on singular G_2 manifolds offers realistic backgrounds that may match
reality. Another way how chiral, asymmetric theories can occur from
M-theory is in the context of M-theory on two-torus which is not a
9-dimensional symmetric theory but a 10-dimensional asymmetric one. LM]
--
m_brain
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"_Superstrings:_A_Theory_of_Everything_?"
They dismiss 11D theory as having a fatal flaw: -"A distinctive element
of the weak interaction is that it breaks left-right mirror symmetry.
This implies that elementary particles must be endowed with a definite
handedness, or 'chirality'...It turns out that definite chirality only
exists in spaces with an odd number of dimensions. This means that
space must have an odd number of dimensions, and hence spacetime must
have an even number of dimensions, otherwise there would be no
chirality in the laws of nature. In short, eleven spacetime dimensions
won't work."-
Any thoughts?
[Moderator's note: While it's true that M-theory on smooth spaces gives
left-right symmetric physics, M-theory compactified on singular spaces
generically leads to asymmetric, chiral theories. This is why M-theory
on singular G_2 manifolds offers realistic backgrounds that may match
reality. Another way how chiral, asymmetric theories can occur from
M-theory is in the context of M-theory on two-torus which is not a
9-dimensional symmetric theory but a 10-dimensional asymmetric one. LM]
--
m_brain
------------------------------------------------------------------------
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View this thread: https://www.physicsforums.com/showthread.php?t=66834
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