A question about metric compatibility equation

  • Context: Undergrad 
  • Thread starter Thread starter Jianbing_Shao
  • Start date Start date
  • Tags Tags
    Metric
Click For Summary
SUMMARY

The discussion centers on the constraints required for a connection to be metric compatible in the context of general relativity (GR) and its extensions. A metric-compatible connection satisfies the equation $$\nabla_\rho g_{\mu\nu}=0$$, which allows for the derivation of the Levi-Civita connection. However, the presence of torsion complicates this relationship, as an arbitrary connection can be expressed as a sum of the Levi-Civita connection and a torsion component. The conversation highlights the distinction between metric-compatible and non-metric-compatible connections, emphasizing that the latter does not necessarily have to be torsion-free.

PREREQUISITES
  • Understanding of vector fields and scalar fields in differential geometry.
  • Familiarity with the concepts of metric compatibility and torsion in general relativity.
  • Knowledge of the Levi-Civita connection and its derivation from metric compatibility.
  • Basic understanding of partial differential equations and their applications in physics.
NEXT STEPS
  • Study the properties of the Levi-Civita connection in detail.
  • Explore the implications of torsion in Einstein-Cartan theory.
  • Investigate the nonmetricity tensor and its role in connection theory.
  • Learn about the mathematical techniques for solving systems of partial differential equations in the context of GR.
USEFUL FOR

The discussion is beneficial for theoretical physicists, mathematicians specializing in differential geometry, and researchers exploring advanced concepts in general relativity and its extensions.

  • #61
Jianbing_Shao said:
I think it perhaps a conbination of rotation invariance of metric and curvature determine the property of path dependence of metric.
It's frustrating when you continue to make these statements about what you "think". What matters is what you can prove! The whole point of my post #46 is to demonstrate (prove!) that the metric ##g## is unchanged by parallel-transport through an infinitesimal-distance along a path by any metric-compatible connection ##\Gamma## (see eq.(10)), regardless of the curvature or torsion. So I must cease commenting in this thread unless you do me the courtesy of one of the following:
  • Prove using equations (not words) that "curvature determine the property of path dependence of metric", or
  • Prove using equations (not words) that there is an error in post #46 that renders eq.(10) invalid, or
  • Acknowledge that eq.(10) is valid and proves that ##g## is invariant when parallel-transported by a metric-compatible ##\Gamma##.
 
  • Like
Likes   Reactions: haushofer and dextercioby
Physics news on Phys.org
  • #62
Thread closed for Moderation...
 
  • #63
After moderator review, this thread will remain closed as the OP question has been sufficiently addressed.
 
  • Like
Likes   Reactions: renormalize

Similar threads

  • · Replies 24 ·
Replies
24
Views
2K
  • · Replies 3 ·
Replies
3
Views
502
  • · Replies 4 ·
Replies
4
Views
1K
  • · Replies 1 ·
Replies
1
Views
980
  • · Replies 10 ·
Replies
10
Views
2K
  • · Replies 9 ·
Replies
9
Views
1K
  • · Replies 2 ·
Replies
2
Views
3K
  • · Replies 38 ·
2
Replies
38
Views
2K
  • · Replies 7 ·
Replies
7
Views
1K
  • · Replies 7 ·
Replies
7
Views
2K