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Abstract:
In conventional world-line formalism for spinning binaries in general relativity, one assumes that the dynamical degrees of freedom for spin are the completely captured by the rest frame canonical spin. A spin supplementary condition (SSC) is then necessary to remove redundancies. We study this problem from an amplitude-based field theory perspective. In higher spin field theories, it is notoriously difficult to impose transverse and traceless conditions when interactions are included. We take an alternative approach and keep the additional degrees of freedom. We see that for generic Wilson coefficients, we obtain a system with additional physical degrees of freedom that has physical effect starting at the quadrupole level. It will decouple when we choose special values for Wilson coefficients, and we land back on the dynamics of conventional spinning binaries. The situation is very similar to a symmetry breaking in the classical limit. We also construct a world-line Lagrangian and a classical effective Hamiltonian that completely match the physics mentioned above, which incorporates such additional dynamical degree of freedom. Such generic spinning objects are realized in a world-line formalism, in which the additional degrees of freedom can be removed through a world-line shift when Wilson coefficients take special values. Finally, we propose a few candidates for such generic spinning bodies.
Biography:
Prof. Fei Teng got his PhD from University of Utah in 2017, and then worked at Uppsala University and Pennsylvania State University as a postdoc researcher, before joining Fudan University in 2024. His research interests are mainly in scattering amplitudes and their applications.
Host: Prof. Kai Yan
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