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Novel Method to Measure the Gravitational Constant

Research Project

Project/Area Number 21K03603
Research Category

Grant-in-Aid for Scientific Research (C)

Allocation TypeMulti-year Fund
Section一般
Review Section Basic Section 15020:Experimental studies related to particle-, nuclear-, cosmic ray and astro-physics
Research InstitutionRikkyo University

Principal Investigator

Zeidler Simon  立教大学, 理学部, 助教 (80773598)

Project Period (FY) 2021-04-01 – 2023-03-31
Project Status Discontinued (Fiscal Year 2022)
Budget Amount *help
¥4,160,000 (Direct Cost: ¥3,200,000、Indirect Cost: ¥960,000)
Fiscal Year 2023: ¥520,000 (Direct Cost: ¥400,000、Indirect Cost: ¥120,000)
Fiscal Year 2022: ¥1,820,000 (Direct Cost: ¥1,400,000、Indirect Cost: ¥420,000)
Fiscal Year 2021: ¥1,820,000 (Direct Cost: ¥1,400,000、Indirect Cost: ¥420,000)
Keywordspolarization stability / noise / coherence / Interferometer / Mach-Zehnder / Laser / Gravity
Outline of Research at the Start

Gravity is one of the four universal forces, but we do not understand it as much as the other three, particularly at microscopic scales. Attempts to measure gravity at very close distances were concentrated up to now only on mechanical approaches which suffer from external influences like electrostatics. Here, I propose a new method by using relativistic effects on laser-light for the measurements which would reduce these influences drastically. As these effects are very small, my research is concentrated on improving the methods for measuring phase distortions due to gravity in laser-light.

Outline of Annual Research Achievements

I succeeded to build a laser Doppler-interferometer, connected to a high-speed sampling oscilloscope, with which oscillation-amplitudes at 1~5kHz below picometer-ranges (<10^-12 m) could be measured. The first attempt of building such an instrument lagged clearly in polarization stability as the measured ground noise could not be lowered below 1pm/Hz^(1/2) even with a maximum sampling rate of 5MHz. The last measured ground noise is now at 0.13pm/Hz^(1/2).
The instrument has experienced upgrades regarding the polarization stability in the form of Glan-Taylor prisms which are now in front of the waveplates on the recombining beam-splitter side and a Faraday isolator at the laser-input. Furthermore, care has been taken to ensure an equal optical path length for both the reference and the signal beam path by using polarization maintaining fibers. This increased the coherence of both beams and thus also the contrast of the observed fringes at the detectors.
One minor aspect of the conducted research was to ensure the usability of the Piezo-test chip even for oszillation amplitudes below a picometer. This is important to keep the dynamic constrast low and thus the resolution of the measurements high. The results clearly proof the capability of the test-chip.

Report

(2 results)
  • 2022 Annual Research Report
  • 2021 Research-status Report
  • Research Products

    (3 results)

All 2022 2021

All Presentation (3 results) (of which Int'l Joint Research: 1 results,  Invited: 1 results)

  • [Presentation] Sub-nm Amplitude Detector Construction for Newton-V Microgravity Measurement2022

    • Author(s)
      Simon Zeidler
    • Organizer
      JPS Spring Meeting
    • Related Report
      2022 Annual Research Report
  • [Presentation] The Search for Deviations from Newton’s Gravity at Micrometer Scales2022

    • Author(s)
      Simon Zeidler
    • Organizer
      General Relativity 23
    • Related Report
      2022 Annual Research Report
    • Invited
  • [Presentation] Novel Method to Measure Gravity at small Distances2021

    • Author(s)
      Simon Zeidler
    • Organizer
      JPS autumn meeting 2021
    • Related Report
      2021 Research-status Report
    • Int'l Joint Research

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Published: 2021-04-28   Modified: 2023-12-25  

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