Inferring Fundamental Spacetime Symmetries with Gravitational-Wave Memory: From LISA to the Einstein Telescope.

Area of Science:

• Astrophysics
• General Relativity
• Gravitational Wave Astronomy

Background:

• Gravitational wave (GW) memory, a subtle but persistent effect in spacetime, has traditionally been a challenging signal to detect.
• Its potential for probing fundamental physics beyond standard GW searches has remained largely unexplored.
• Understanding GW memory is crucial for advancing our knowledge of gravity and the universe.

Purpose of the Study:

• To establish gravitational wave memory as a tool for measuring spacetime symmetries.
• To investigate the potential of displacement and spin memory for probing these symmetries.
• To assess the impact of neglecting memory effects on binary black hole merger parameter estimations.

Main Methods:

• Theoretical analysis of gravitational wave memory effects.
• Simulations incorporating the Einstein Telescope's (ET) projected sensitivity.
• Quantification of measurement uncertainties for binary black hole merger parameters.

Main Results:

• Displacement and spin memory can be used to probe spacetime symmetries.
• The Einstein Telescope can constrain displacement memory strain amplitude to 2% and spin memory to 22%.
• Neglecting memory effects can lead to ~10% overestimation of BBH merger parameter uncertainties in ET.

Conclusions:

• Gravitational wave memory is a key observable for measuring spacetime symmetries.
• The Einstein Telescope will provide unprecedented precision in constraining memory effects.
• Accurate modeling of GW memory is essential for precise astrophysical parameter estimation.