TY - JOUR

T1 - Cosmology and Warped Space Times in Dynamical String Tension Theories

AU - Guendelman, Eduardo

PY - 2021/4/1

Y1 - 2021/4/1

N2 - The string and brane tensions do not have to be put in by hand, they can
be dynamically generated, as in the case when we formulate string and
brane theories in the modified measure formalism. Then string and brane
tensions appears, but as an additional dynamical degree of freedom . It
can be seen however that these string or brane tensions are not
universal, but rather each string and each brane generates its own
tension, which can have a different value for each string or brane. We
define a new background fields that can couple to this new type of
extended objects, the tension scalar is capable of changing locally
along the world sheet the value of the tension of the extended object.
When many strings probing the same region of space are considered this
tension scalar is constrained by the requirement of quantum conformal
invariance. For the case of two strings probing the same region of space
with different dynamically generated tensions, there are two different
metrics, associated to the different strings, that have to satisfy
vacuum Einstein equations and the consistency of these two Einstein
equation determines the tension scalar. The universal metric, common to
both strings generically does not satisfy Einstein equation . The
problem is analyzed for Schwarzschild background and for Kasner type
space, for the Milne representation, for the case of two types of string
tensions, with solutions with negative string tension at the early
universe and a positive string tension that appears for the late
universe . The universal metric is not flat, instead it represents a non
singular bounce cosmology. The case in a warped space time where
positive and and negative string tensions are separated by a
spontaneously generated wall is also studied.

AB - The string and brane tensions do not have to be put in by hand, they can
be dynamically generated, as in the case when we formulate string and
brane theories in the modified measure formalism. Then string and brane
tensions appears, but as an additional dynamical degree of freedom . It
can be seen however that these string or brane tensions are not
universal, but rather each string and each brane generates its own
tension, which can have a different value for each string or brane. We
define a new background fields that can couple to this new type of
extended objects, the tension scalar is capable of changing locally
along the world sheet the value of the tension of the extended object.
When many strings probing the same region of space are considered this
tension scalar is constrained by the requirement of quantum conformal
invariance. For the case of two strings probing the same region of space
with different dynamically generated tensions, there are two different
metrics, associated to the different strings, that have to satisfy
vacuum Einstein equations and the consistency of these two Einstein
equation determines the tension scalar. The universal metric, common to
both strings generically does not satisfy Einstein equation . The
problem is analyzed for Schwarzschild background and for Kasner type
space, for the Milne representation, for the case of two types of string
tensions, with solutions with negative string tension at the early
universe and a positive string tension that appears for the late
universe . The universal metric is not flat, instead it represents a non
singular bounce cosmology. The case in a warped space time where
positive and and negative string tensions are separated by a
spontaneously generated wall is also studied.

KW - High Energy Physics - Theory

KW - General Relativity and Quantum Cosmology

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JO - arxiv hep-th

JF - arxiv hep-th

ER -