Spin–torsion interaction and geodesic bending
- 1S. N. Bose National Centre for Basic Sciences
Abstract
The intrinsic spin of fermions induces torsion in spacetime, leading to an effective four-fermion interaction. This affects the bending of null and timelike geodesics inside a star with a spherically symmetric distribution of gravitationally dense fermionic matter of constant density. Our analysis shows an additional torsional contribution to the geodesic deflection, alongside the conventional curvature-induced effect. This change depends on the fermion number density, coupling constants of the different species of fermions with different chiralities, and the temperature of the matter distribution. We have shown that the torsion-induced corrections to null geodesic bending remains very small for both low- and high-mass white dwarfs, whereas significantly larger effects may arise in more compact astrophysical objects such as neutron stars.
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BibTeX
@article{maity2026spintorsion,
title = {{Spin–torsion interaction and geodesic bending}},
author = {Sagar Kumar Maity and Amitabha Lahiri},
journal = {The European Physical Journal C},
year = {2026},
month = nov,
doi = {10.1140/epjc/s10052-026-16546-7},
url = {https://link.springer.com/article/10.1140/epjc/s10052-026-16546-7},
note = {CC BY 4.0},
}
RIS
TY - JOUR
TI - Spin–torsion interaction and geodesic bending
AU - Sagar Kumar Maity
AU - Amitabha Lahiri
PY - 2026
DA - 2026/11/09
JO - The European Physical Journal C
DO - 10.1140/epjc/s10052-026-16546-7
UR - https://link.springer.com/article/10.1140/epjc/s10052-026-16546-7
AB - The intrinsic spin of fermions induces torsion in spacetime, leading to an effective four-fermion interaction. This affects the bending of null and timelike geodesics inside a star with a spherically symmetric distribution of gravitationally dense fermionic matter of constant density. Our analysis shows an additional torsional contribution to the geodesic deflection, alongside the conventional curvature-induced effect. This change depends on the fermion number density, coupling constants of the different species of fermions with different chiralities, and the temperature of the matter distribution. We have shown that the torsion-induced corrections to null geodesic bending remains very small for both low- and high-mass white dwarfs, whereas significantly larger effects may arise in more compact astrophysical objects such as neutron stars.
SN - 1434-6052
ER -