Cauchy-Characteristic Extraction (CCE) at Null Infinity with CarpetX and SpECTRE

Driven by the need for higher accuracy gravitational waveforms, recent advances in modeling techniques and numerical relativity have shed light on the importance of extracting signals at future null infinity where they are free from gauge and finite radius effects. In this talk, I will present ongoing work on extending the Einstein Toolkit’s (ETK) waveform extraction capabilities by implementing the current Cauchy-Characteristic Extraction module (CCE_Export) within CarpetX – the next generation Adaptive Mesh Refinement (AMR) driver for ETK. This development establishes a new computational pipeline linking ETK’s Cauchy evolutions with the CCE module from SpECTRE – another next generation open-source numerical relativity code developed by the Simulating eXtreme Spacetime collaboration – enabling gauge invariant waveform extractions at null infinity. I will discuss implementation details, compatibility challenges and preliminary results comparing CCE waveforms to finite radius extrapolation in binary black hole simulations. This work lays a foundation for accurate waveform extraction in next generation relativity codes applications for both general relativity and modified gravity.