Testing Lorentz Invariance with an Optical Cavity Yuta Michimura - - PowerPoint PPT Presentation

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Testing Lorentz Invariance with an Optical Cavity Yuta Michimura - - PowerPoint PPT Presentation

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Lunch Talk (Department of Physics, University of Tokyo) November 20, 2015 Testing Lorentz Invariance with an Optical Cavity Yuta Michimura Department of Physics, University of Tokyo Self Introduction Assistant Professor(

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Testing Lorentz Invariance with an Optical Cavity

Yuta Michimura

Department of Physics, University of Tokyo

Lunch Talk (Department of Physics, University of Tokyo) November 20, 2015

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  • Assistant Professor(助教), Ando Group

from July 2014

  • Gravitational Waves
  • DECIGO Pathfinder

prototype experiment

  • KAGRA

main interferometer design & development

  • Test of Lorentz Invariance
  • anisotropy search in the speed of light

asymmetric optical ring cavity

  • “interferometry for fundamental physics”

macroscopic quantum mechanics, test of gravitational inverse square law, dark matter search etc……

Self Introduction

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DECIGO Pathfinder KAGRA

  • ptical ring cavity
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  • Large-scale Cryogenic Gravitational wave Telescope

being built in Kamioka mine, Gifu

  • initial phase observation run in FY2015
  • room temperature
  • 3km Michelson
  • final phase observation run in ~ FY2017
  • cryogenic temperature (20K)
  • 3km RSE

KAGRA

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iKAGRA (FY2015) bKAGRA (~ FY2017)

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  • inauguration
  • f initial stage

facility

  • mirror installation
  • ngoing
  • very exciting stage!

Recent KAGRA News

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2015年11月6日 朝日新聞 2015.10.30

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  • LI could only be an approximate
  • test isotropy of the speed of light
  • two-way test (Michelson-Morley type)

has been tested to level

  • one-way test (our type)

tested to level

Test of Lorentz Invariance

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an order of magnitude improvement

  • M. Nagel+, Nature Communications 6,8174 (2015)
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SLIDE 6
  • compare resonant frequencies of counter-

propagating modes of asymmetric optical ring cavity

Asymmetric Optical Ring Cavity

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no violation CCW CW

no dielectric dielectric

Lorentz violation resonant

  • freq. shift

∝ LV

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  • double-pass configuration for null measurement

Method for Frequency Comparison

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Laser counter-clockwise clockwise Lorentz violation signal frequency servo dielectric photo- diodes

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  • frequency comparison using double-pass setup
  • rotate and modulate LV signal

rotate

Experimental Setup

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silicon

LV signal

collimator frequency servo vacuum enclosure (0.1-1kPa) fiber

turntable ring cavity

Laser

extract LV from amplitude

1550 nm

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Photo of the Optics

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ring cavity PDs1 PDp1 PDs2 PDp2 collimator Inside vacuum enclosure (30cm×30cm×17cm)

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Photo of the Whole Setup

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laser source vacuum enclosure + shielding (optics inside) turntable electrical cables 40 cm

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  • 12 sec / rotation, alternately

Rotation

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Observation Data

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  • from July 2012 to October 2013
  • 393 days, 1.67 million rotations
  • duty cycle: 53% (64% after Oct 2012)
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  • demodulate data with and then

Data Analysis

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sidereal X Y Z turntable Sun Earth

360 deg rotational symmetry

acquired LV signal demodulation amplitudes are modulated by sidereal frequency frequency

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Demodulation Amps

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  • zero consistent at 2σ

no significant LV can be claimed at

average over 393 days 1 day data

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  • current noise level is limited by vibration noise from

rotation

  • semi-monolithic
  • ptical bench to

reduce vibration sensitivity

  • continuous rotation for more stable operation
  • aim to have reduced noise by ~ 1/100

Upgrade of the Apparatus

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stationary when rotating

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Apparatus Comparison

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turntable laser semi- monolithic

  • ptics

vacuum enclosure data logger AC power turntable laser non- monolithic

  • ptics

vacuum enclosure data logger AC power slip ring

2012 Model

  • non-monolithic optics
  • alternative rotation

New Model

  • semi-monolithic optics
  • continuous rotation
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  • assembly mostly done
  • stationary noise higher than before
  • investigation ongoing (scattering?)

Current Status of the New Model

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work done by Jake Guscott (undergrad from U of Adelaide)

when rotating (old) stationary (old) stationary (new)

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  • compared the speed of light propagating in
  • pposite directions
  • using a double-pass optical ring cavity
  • put new limits on Lorentz violation in photons
  • currently developing an upgraded apparatus
  • Y. Michimura+, Phys. Rev. Lett. 110, 200401 (2013)
  • Y. Michimura+, Phys. Rev. D 88, 111101(R) (2013)
  • supported by JSPS科研費 若手A 15H05445

Summary

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