new optical tests of relativity on earth and in...
TRANSCRIPT
New Optical Tests of Relativityon Earth and in Space
38th Recontres de Moriond, March 2003, Les Arcs, FranceAchim Peters
Contents
OPTIS – a satellite test of Special and General Relativity
A modern Michelson-Morley experimentusing cryogenic optical resonators (COREs)
Motivation
Results and prospects
Summary
Motivation
Relativity and Quantum Mechanicsare the foundation of modern physics
Improved technology makes new tests possible
Unified theories (String-theory, etc...)predict violations of Special Relativity
New frameworks for describing general violations of Special Relativity have been developed recently
Theory of Relativity
General Relativity (Einstein 1915): gravitation
Special Relativity (Einstein 1904)
velocityinvariance
isotropy universalityof free fall
local positioninvariance
time dilation
Experimental limits (2000)
! Velocity invariance ∆c/c < 2.10-13 |A| < 7.10-5
(Hils and Hall, 1990)
! Isotropy ∆c/c < 6.10-15 |B| < 6.10-9
(Brillet and Hall, 1979)
! Time dilation measurement violation < 10-7
(Isaak, 1970, Riis et al. 1988)
! Mansouri-Sexl test theory:
Assumed preferred frame: microwave background
Lorentz transformations confirmed at 7.10-5 level
∆cc = A
v2
c2 + Bv2
c2 sin2 θ
MM-experiments old & new
Frequency stabilization to a cavity
laser 1
PD
BS
servo
L
stable referencecavity
frequency analysis
Kennedy-Thorndike experiment
c
comparison
atomic clock
velocity of laboratory
Movement of Earth in space
Why Sapphire COREs ?
Low thermal expansion coefficient:Sapphire @ 1.5 K: 2·10-12 / KULE @ 300 K: 1·10-8 / K
Pure crystalline material at cryogenic temperatures:No (or very small) relaxation processes
Very high long-term stabilty: < 20 Hz / day (vs ~ 5 kHy / day for ULE @ 300 K)
Performance of COREs
Analysis of beatnote measurements between independent free-beam- or fiber-coupled CORES
MM-experiment using COREs
MM-experiment using COREsBeam alignment
control
Technical details:
3fm-PDH-Lock:demodulate at 3rd harmonicinsensitive to residual AMOffset compensation:Measure and compensate effectsof residual AM, residual etalons,mixer offsets, electrical offsets, ...Active beam pointing:Stabilize incoupling, compensate for cryo movements
Typical measurement - raw dataFeb. 05, 2002Red points: 2 min averagesoff-lock periods removed
Freq
uenc
y de
viat
ion
[Hz]
3 days
100 Hz
Time [days]
Data analysis – single measurement
Data analysis – complete data
Standard Model Extension (SME)
Analysis within SME
Future prospects
New, improved cryostat
Turntable, optimized rotation
Crossed monolithic COREs
Rotating CryostatPVLAS vacuum birefringence experiment
Fiber coupled resonators
Future Prospects- In Space -
OPTIS
Mission study funded by
Heinrich-Heine-Univ.
Universität Düsseldorf
• C. Lämmerzahl
• S. Schiller
ZARM, Univ. Bremen
• H. Dittus
Humboldt-Univ. Berlin
(formerly Univ. Konstanz)
• A. Peters
Satellite-based tests of Special and General Relativity
Mission Idea
• Michelson-Morley
• Kennedy-Thorndike• Gravitational redshift
U2(r)
U1(r)
v1
v2
fs Comb
Summary and Outlook
Improved MM-experiment(3 orders of magnitude)
Improved KT-experiment(1 order of magnitude)
Other fundamental tests ...
No reason to worry, yet ...
COREs are suitable tools for tests of fundamental physicsMichelson-Morley experiment: 3-fold improvement Standard Model Extension parameters: 100-fold improvement
Space based experiments
The team
Holger Müller, Achim Peters, Oliver Pradl, Claus Braxmaier,Sven Herrmann, and Alexsandro Sunaga
MM-experiment using COREsBeam alignment
control
Setup for measuring stability
Spacecraft and orbit"" MassMass 250 kg250 kg
"" Power Power budget budget 250 W250 W
"High elliptic orbit"Period: 14 h"Inclination 63°"Shadow:
5 months without shadow1 month with periods
"Sun rad. press. 4.4 µN/m2
"Earth albedo rad. press.1.2 µN/m2
GTO
HEO
Apogee motorfor orbit transfer
FEEPs:∆F = ± 0.1 µNFmax = 100 µN
+ Reference sensorδa=10-14 m/(s2·# Hz)
In(Cs) Reservoir
ONERA
Cold gas thrusterfor coarse attitude control
Analysis within SME
Sapphire COREs