https://doi.org/10.1140/epjp/s13360-026-07827-x
Regular Article
Thermal lag effect in torsion pendulum for gravitational experiment
1
Faculty of Information Engineering, Quzhou College of Technology, 324000, Quzhou, People’s Republic of China
2
MOE Key Laboratory of TianQin Mission, TianQin Research Center for Gravitational Physics & School of Physics and Astronomy, Frontiers Science Center for TianQin, Gravitational Wave Research Center of CNSA, Sun Yat-sen University (Zhuhai Campus), 519082, Zhuhai, People’s Republic of China
3
National Gravitation Laboratory, MOE Key Laboratory of Fundamental Physical Quantities Measurement and Hubei Key Laboratory of Gravitation and Quantum Physics, Huazhong University of Science and Technology, 430074, Wuhan, People’s Republic of China
a
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b
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Received:
6
April
2026
Accepted:
12
May
2026
Published online:
31
May
2026
Abstract
Here we present a thermal lag effect in the torsion pendulum for gravitational experiments. Using ambient room-temperature fluctuations for passive modulation, we observe that the equilibrium position of the pendulum lags the temperature change by approximately 3.85 h, corresponding to an angular change of 
. This lag behavior goes beyond the temperature-related effects previously considered in torsion pendulum gravitational experiments. We demonstrate that the low frequency noise of the torsion pendulum is dominated by the thermal lag effect. It is suggested that the effect should be carefully evaluated and corrected in a precision gravitational experiment.
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© The Author(s), under exclusive licence to Società Italiana di Fisica and Springer-Verlag GmbH Germany, part of Springer Nature 2026
Springer Nature or its licensor (e.g. a society or other partner) holds exclusive rights to this article under a publishing agreement with the author(s) or other rightsholder(s); author self-archiving of the accepted manuscript version of this article is solely governed by the terms of such publishing agreement and applicable law.
