Undergrad Is the weak field limit valid for the Brans-Dicke scalar field?

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SUMMARY

The Brans-Dicke theory, a scalar-tensor modification of general relativity, has been validated through solar system experiments indicating that the parameter ##\omega > 40000##, rendering it nearly indistinguishable from general relativity (GR). These experiments rely on the weak field limit, where the scalar field is expressed as ##\phi = \phi_0 + \xi##. However, the validity of this weak field limit is questioned when considering long-range scalar fields, as they may incorporate contributions from all mass in the Universe, affecting the scalar field at any point in space.

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  • Understanding of Brans-Dicke theory and its implications in cosmology
  • Familiarity with scalar-tensor theories in general relativity
  • Knowledge of solar system experiments validating gravitational theories
  • Concept of weak field limits in gravitational physics
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  • Research the implications of long-range scalar fields in Brans-Dicke theory
  • Study the mathematical formulation of the weak field limit in scalar-tensor theories
  • Examine solar system experiments that test modifications to general relativity
  • Explore the relationship between scalar fields and gravitational effects in cosmology
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Physicists, cosmologists, and researchers interested in gravitational theories, particularly those exploring modifications to general relativity and the implications of scalar fields in cosmology.

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The Brans-Dicke theory is a scalar-tensor modification of general relativity that has been tested against solar system experiments which show that the parameter ##\omega \gt 40000## implying that the theory is almost indistinguishable from GR.

These tests assume the weak field limit of the theory so that the scalar field ##\phi = \phi_0 + \xi##.

But is this valid if the scalar field is long range so that all the mass in the Universe at any distance contributes to ##\phi## at any given point in space?
 

Thread 'EPR revisited'

In an inertial frame of reference (IFR), there are two fixed points, A and B, which share an entangled state $$ \frac{1}{\sqrt{2}}(|0>_A|1>_B+|1>_A|0>_B) $$ At point A, a measurement is made. The state then collapses to $$ |a>_A|b>_B, \{a,b\}=\{0,1\} $$ We assume that A has the state ##|a>_A## and B has ##|b>_B## simultaneously, i.e., when their synchronized clocks both read time T However, in other inertial frames, due to the relativity of simultaneity, the moment when B has ##|b>_B##...
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