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EMRI Resummation — Sensitivity to Interpolation Errors

Resummed energy loss in extreme-mass-ratio scattering using critical orbits

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What the paper says

The resummation method captures the divergence structure near critical orbits.

The Critique

The method relies on interpolation of 'highly accurate numerical data' for fluxes along unstable circular geodesics, but they don't quantify how sensitive the resummation is to errors in this interpolation. Unstable geodesics are exponentially sensitive to initial conditions—small errors in the interpolation could propagate into large errors in the resummed results.

Why It Matters

Extreme-mass-ratio inspirals (EMRIs) are prime sources for LISA. If the resummation method has hidden sensitivities or limited applicability, this affects waveform modeling for gravitational wave astronomy.

What They Missed

They don't address whether the method works when the background spacetime is not Kerr (e.g., with matter effects, modified gravity).