2026/02/26 by Amit Singh Ubhi, Lari Koponen, Jiri Smetana +11 · 1 citation
Physics and Astronomy · Engineering · Earth and Planetary Sciences · #Pulsars and Gravitational Waves Research #Geophysics and Sensor Technology #Geophysics and Gravity Measurements
paper · pdf · doi:10.1103/65gz-dcjz
Extending the sensitivity of terrestrial gravitational-wave detectors below 20 Hz is a long-standing challenge, limited by ground motion and inertial sensing noise. In this Letter, we demonstrate ultra-high-vacuum compatible inertial isolation and position sensing technologies that achieve active platform stabilization down to 10 mHz. Our laser position sensors reach a <a:math xmlns:a="http://www.w3.org/1998/Math/MathML" display="inline"> <a:mrow> <a:mi>sub</a:mi> <a:mtext>−</a:mtext> <a:mi>pm</a:mi> <a:mo>/</a:mo> <a:msqrt> <a:mrow> <a:mi>Hz</a:mi> </a:mrow> </a:msqrt> </a:mrow> </a:math> sensitivity above 10 mHz, independent of the input light polarization, representing a 100-fold improvement over the current LIGO position sensors. In addition, our inertial sensors provide at least a factor of 5 improvement in low-frequency sensitivity compared to state-of-the-art commercial seismometers. We integrate these technologies into a LIGO-like interferometer model and predict a low-frequency sensitivity improvement of up to an order of magnitude at 10 Hz, with enhanced linearity and calibration stability. This extension increases the detection horizon for intermediate-mass black hole binaries of mass <c:math xmlns:c="http://www.w3.org/1998/Math/MathML" display="inline"> <c:mrow> <c:msup> <c:mrow> <c:mn>10</c:mn> </c:mrow> <c:mrow> <c:mn>3</c:mn> </c:mrow> </c:msup> <c:msub> <c:mrow> <c:mi>M</c:mi> </c:mrow> <c:mrow> <c:mo stretchy="false">⊙</c:mo> </c:mrow> </c:msub> </c:mrow> </c:math> by a factor of 3 and increases the SNR for all lower mass binaries. Our results provide the first experimental demonstration of a practical pathway to sub-10 Hz operation of terrestrial gravitational-wave detectors and establish key technologies for next-generation observatories such as Cosmic Explorer and Einstein Telescope.