عنوان مجله
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European Physical Journal Plus
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چکیده
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In the present work we study collapse process of a homogeneous and isotropic fluid in Brans–Dicke (BD) theory with
non-vanishing spacetime torsion. In this theory, torsion can be generated by the BD scalar field as well as the intrinsic angular
momentum (spin) of matter. Assuming the matter content of the collapsing body to be a Weyssenhoff fluid, which is a generalization
of perfect fluid in general relativity (GR) in order to include the spin effects, we find that in BD theory with torsion, the existence
of spin effects could avoid the spacetime singularity that forms in the original version of this theory (Scheel et al. in Phys Rev
D 51:4208, 1995, Scheel et al. in Phys Rev D 51:4236, 1995). Numerical simulations of collapse model show that the spacetime
singularity is replaced by a non-singular bounce, the spacetime event at which the collapse process halts at a minimum radius and
then turns into an expanding phase. Moreover, the model parameters can be set so that the apparent horizon will never meet the
boundary of the collapsing body so that the bounce event can be detectable by external observers in the Universe.
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