theoretical modified GR metric

In addition to the well-accepted metrics associated with general relativity (GR) are metrics invented to explore possible modifications to GR. Motivations for such modifications include explaining dark energy (and/or possibly dark matter) and observations that require some kind of new physics, such as some new wrinkle in gravity. Among the experimental metrics:

• QK metric - "quasi-Kerr metric".
• BK metric - "bumpy Kerr metric".
• MN metric - "Manko and Novikov metric".
• JP metric - "Johannsen-Psaltis metric".
• MGBK metric - "modified GR bumpy Kerr metric".
• CS metric - "Chern-Simons metric".

Each represents a model of gravity, and may be cited as such, e.g., Chern-Simons gravity.