- #1
oquen
- 109
- 1
I'm reading the 100 years anniversary edition of Sci-am and there is an article called "The Search for Relativity Violations". Some passages perplexed me:
"In the case of relativity violations,
the equations describing the stick and
the applied force are replaced by the
equations of the ultimate theory. In
place of the stick are the quantum fields
of matter and forces. The natural background
strength of such fields is usually
zero. In certain situations, however,
the background fields acquire a nonzero
strength. Imagine that this happened
for the electric field. Because the electric
field has a direction (technically, it is a
vector), every location in space will
have a special direction singled out by
the direction of the electric field. A
charged particle will accelerate in that
direction. Rotational symmetry is broken
(and so is boost symmetry). The
same reasoning applies for any nonzero
“tensor” field; a vector is a special case
of a tensor.
Such spontaneous nonzero tensor
fields do not arise in the Standard Model,
but some fundamental theories, including
string theory, contain features
that are favorable for spontaneous
Lorentz breaking."
It mentioned electric field breaks Lorentz symmetry yet it added the standard model doesn't break Lorentz symmetry.. isn't electric field part of the standard model?
When you add magnetic field to electric field to become electromagnetic field.. does it break Lorentz symmetry (so called rotational symmetry and boost symmetry)
And what does it mean the fundamental theory may break Lorentz symmetry. Is the consequence for example the strings may all be non-locally connected throughout the universe but at large scale, relativity is a low energy limit. But if the strings can communicate.. won't this cause backward in time causality problem in the low energy limit? How do you make it compatible the low energy obey relativity while at high energy it doesn't?
"In the case of relativity violations,
the equations describing the stick and
the applied force are replaced by the
equations of the ultimate theory. In
place of the stick are the quantum fields
of matter and forces. The natural background
strength of such fields is usually
zero. In certain situations, however,
the background fields acquire a nonzero
strength. Imagine that this happened
for the electric field. Because the electric
field has a direction (technically, it is a
vector), every location in space will
have a special direction singled out by
the direction of the electric field. A
charged particle will accelerate in that
direction. Rotational symmetry is broken
(and so is boost symmetry). The
same reasoning applies for any nonzero
“tensor” field; a vector is a special case
of a tensor.
Such spontaneous nonzero tensor
fields do not arise in the Standard Model,
but some fundamental theories, including
string theory, contain features
that are favorable for spontaneous
Lorentz breaking."
It mentioned electric field breaks Lorentz symmetry yet it added the standard model doesn't break Lorentz symmetry.. isn't electric field part of the standard model?
When you add magnetic field to electric field to become electromagnetic field.. does it break Lorentz symmetry (so called rotational symmetry and boost symmetry)
And what does it mean the fundamental theory may break Lorentz symmetry. Is the consequence for example the strings may all be non-locally connected throughout the universe but at large scale, relativity is a low energy limit. But if the strings can communicate.. won't this cause backward in time causality problem in the low energy limit? How do you make it compatible the low energy obey relativity while at high energy it doesn't?
