Eccentric extreme mass-ratio inspirals: a gateway to probe quantum gravity effects

Abstract We examine a loop quantum gravity (LQG) inspired rotating black hole, treating it as a central supermassive black hole (SMBH) in an extreme mass-ratio inspiral (EMRI) system, where an inspiralling object exhibits eccentric motion around the SMBH. With the orbital dynamics, we derive analytical expressions for the rate of change of orbital energy and angular momentum, as well as orbital evolution, and subsequently generate the gravitational waveforms. To evaluate the difference between EMRI waveforms emitted from the Kerr black hole and a spinning black hole in LQG, we compute the dephasing and mismatch using the Laser Interferometer Space Antenna (LISA) observation. Our result indicates that LISA can distinguish the modified effect of LQG with a parameter as small as $$2\times 10^{-6}$$ <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:mrow> <mml:mn>2</mml:mn> <mml:mo>×</mml:mo> <mml:msup> <mml:mn>10</mml:mn> <mml:mrow> <mml:mo>-</mml:mo> <mml:mn>6</mml:mn> </mml:mrow> </mml:msup> </mml:mrow> </mml:math> . The constraint on a parameter in LQG using the Fisher information matrix can be obtained within a fraction error of $$10^{-6}$$ <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:msup> <mml:mn>10</mml:mn> <mml:mrow> <mml:mo>-</mml:mo> <mml:mn>6</mml:mn> </mml:mrow> </mml:msup> </mml:math> .