Discussion Overview
The discussion centers on the potential experiments that could differentiate Einstein-Cartan gravity from General Relativity (GR). Participants explore theoretical implications, experimental challenges, and the role of spin and torsion in these gravitational theories.
Discussion Character
- Exploratory
- Technical explanation
- Debate/contested
Main Points Raised
- One participant suggests that Einstein-Cartan gravity and GR are equivalent in vacuum but differ in the presence of matter due to torsion in the Einstein-Cartan metric.
- Another participant notes the lack of observational evidence for torsion, emphasizing that current tests of GR against alternative theories rely on macroscopic objects rather than spin.
- A participant mentions an attempt by researchers at the University of Washington to create a high angular momentum source to test spin-dependent gravity, although they express uncertainty about the sensitivity of the device.
- One participant raises the idea that the alignment of spins in neutron stars could lead to modifications in the equilibrium state of the stars, suggesting a possible avenue for exploration.
- A reference to Poplawski's work on Einstein-Cartan theory is provided, highlighting that while it has a high citation count, it may not yield experimentally testable predictions relevant to the current inquiry.
- Another participant mentions their advisor's work on Einstein-Cartan cosmologies, indicating ongoing research in this area.
Areas of Agreement / Disagreement
Participants express differing views on the feasibility of distinguishing between Einstein-Cartan gravity and GR through experiments. There is no consensus on specific experimental methods or the implications of torsion and spin.
Contextual Notes
Some limitations include the dependence on macroscopic descriptions of matter and unresolved questions regarding the sensitivity of proposed experimental setups.
Who May Find This Useful
This discussion may be of interest to researchers in theoretical physics, particularly those focused on gravitational theories, cosmology, and experimental physics related to gravity.