Tests of the Equivalence Principle| Tests of the Equivalence Principle |
In General > s.a. eötvös experiment
and fifth force; quantum equivalence principle.
* Idea: Possible
consequences of a small violation of the equivalence principle include
small differences in the free-fall acceleration of different materials,
and a rotation of the plane of polarization for linearly polarized
radiation propagating over cosmological distances.
* History: The earliest
recorded test was by Galileo; The best experimental test is to compare the
free-fall acceleration of different materials; Late 1800s, validated to
one part in 108 by the Eötvös
experiment; 2001, Eöt-Wash experiments on the weak principle,
the best tests so far, confirm it up to corrections of order
10−13 and have reached their thermal
limit; 2004, The most accurate experiment with atoms shows no departure [@ news
pw(04)nov];
2016, MICROSCOPE launched.
* Of the strong equivalence principle:
2003, The only technique available to test it is Lunar Laser Ranging (>
see tests of general relativity);
2004, results give \(\Delta(m_{\rm g}/m_{\rm i})_{\rm SEP}\) = \((-2.0 \pm 2.0)
\times 10^{-13}\), and \(\eta:= 4\beta-\gamma-3 = (4.4 \pm 4.5) \times 10^{-4}\).
* Results from the Nordtvedt effect:
Experiments give \(m_{\rm g}/m_{\rm i}\) = 1 + \(\eta(U_{\rm G} / mc^2)\),
with \(\eta < 10^{-12}\) so far.
* Results with self-energy:
Satisfied up to 10−3 [@ Baeßler et al
PRL(99),
news PT(99)nov].
* Plans: 2004, NASA-ESA STEP
(Satellite Test of the Equivalence Principle) to be put in orbit in 2005, aims at
\(10^{-18}\) accuracy; SEE (Satellite Energy Exchange); GReAT experiment, involving a
free fall by 4 km in the stratosphere, will test the wep to 1 part in \(5 \times 10^{15}\)
at 95% cl, 100 times better than ground-based; 2005, MICROSCOPE
(MICRO-Satellite à trainée Compensée pour l'Observation du Principe
d'Équivalence) scheduled for 2008, will measure differential acceleration
of test masses in a rotating spacecraft to better than 1 part in \(10^{15}\);
2010, MICROSCOPE now scheduled for 2012 launch;
2012, MICROSCOPE now scheduled for 2016 launch, Galileo Galilei
(GG) mission planned, with accuracy of 1 part in \(10^{17}\), and STEP is still only
a design concept; 2014, STE-QUEST (as opposed to MICROSCOPE
and STEP) will use fundamentally quantum-mechanical systems.
@ Status, reviews: Damour CQG(96)gq, gq/97-proc;
news pw(05)jan;
news NASA(07)may;
issue CQG(12)#18;
news Sci(15)mar;
Schlippert et al a1507-proc [Earth-based tests];
Tino et al PPNP(20)-a2002 [and precision gravity tests].
@ General references:
Gabriel & Haugan PRD(90);
Klein & Mittelstaedt AJP(97)apr [demo];
CPLEAR collaboration PLB(99) [K0s];
Haugan & Lämmerzahl LNP(01)gq;
Luo et al PRD(02)gq/01 [rotation];
Gundlach NJP(05) [lab tests];
Newburgh EJP(08) [simple demonstration];
Hohensee et al PRL(11)-a1102 [matter-wave redshift experiments and clock comparisons];
Hohensee & Müller JMO(11)-a1106 [with matter waves];
Unnikrishnan & Gillies CQG(12);
Hohensee & Müller proc(14)-a1307
[differences between spaceborne and quantum mechanical tests, and conventional tests];
Nobili PRD(16)-a1608 [smallness of general relativistic effects on experiments].
Specific Systems and Experiments > s.a. fine-structure constant;
neutrino experiments; neutrino oscillations;
tests of general relativity with light.
* Cosmology: A field non-minimally coupled
to the electromagnetic Lagrangian can induce a violation of the Einstein equivalence
principle, which in a cosmological context would break the validity of the cosmic distance
duality relation and cause a time variation of the fine structure constant.
@ Spin-gravity coupling: Silenko & Teryaev PRD(07)gq/06;
Tarallo et al PRL(14)-a1403
+ Phys(14)jul [search for effects on different falling Sr isotopes];
Hojman & Asenjo a1610
[testing the universality of free fall as opposed to spin-gravity coupling].
@ Neutrino oscillations:
Halprin et al PRD(96);
Fogli et al PRD(99)hp;
Datta PLB(01).
@ STEP mission: Sumner GRG(04);
Overduin et al ASR(09)-a0902;
Overduin et al CQG(12)-a1401;
Pereira et al PRL(16)-a1607 [as a test of MOND].
@ MICROSCOPE experiment:
Touboul et al CQG(12);
Bergé et al JPCS(15)-a1501 [status];
Pihan-Le Bars et al a1705;
Hardy et al SSR(17)-a1707 [signal processing];
Touboul et al PRL(17)
+ news sn(17)dec,
Touboul et al CQG(19)-a1909 [first results];
> s.a. MICROSCOPE site.
@ Other Earth satellites:
CQG(01)#13 issue;
Moffat & Gillies NJP(02)gq [wep];
Nobili et al PLA(03),
CQG(12) [GG proposal];
Iorio GRG(04)gq/03 [wep];
Nobili et al GRG(08) [LAGEOS and LAGEOS II, limitations];
Ni PRL(11)-a1105 [Gravity Probe B and wep II];
Aguilera et al CQG(14)-a1312,
Altschul et al ASR(15)-a1404
[STE-QUEST proposed satellite mission, using cold-atom interferometry];
Williams et al NJP(16)-a1510 [QTEST, on the ISS];
Nobili & Anselmi PLA(18)-a1709 [expected improvements];
Nobili & Anselmi PRD(18)-a1803 [after MICROSCOPE];
Ciufolini et al a1907.
@ Solar system:
Anderson et al ap/95-conf,
ApJ(96)ap/95 [Earth-Mars ranging];
Overduin PRD(00)gq [and higher-dimensional gravity];
Shiomi PRD(06)-a0811 [geophysical];
Rubincam PRD(11) [Mars seasonal polar caps];
Williams et al CQG(12),
Murphy et al CQG(12) [lunar laser ranging];
Overduin et al CQG(14)-a1307;
De Marchi & Congedo IJMPD(17)-a1702
[experiment to measure η on the future mission BepiColombo];
> s.a. gravitational redshift.
@ Of the strong equivalence principle: Congedo & De Marchi PRD(16)-a1602 [spacecraft near Lagrangian points];
news sn(18)jan [triple star system].
@ Binary pulsars:
Wex A&A-gq/95 [proposal];
Arzoumanian ap/02-proc.
@ Extragalactic transient sources: Wei et al PRL(15)-a1512,
Tingay & Kaplan ApJL(16)-a1602 [fast radio bursts];
Nusser ApJL(16)-a1601 [tighter constraints];
Wang et al PRL(16)-a1602 [PeV neutrinos from blazar flares];
Sang et al MNRAS(16)-a1605 [short GRBs and the PPN parameter γ];
Yang et al MNRAS(17)-a1706 [polarized GRBs];
Yu et al ApJ(18)-a1708 [robust method using time delays];
Tangmatitham & Nemiroff a1903 [cosmological GRBs];
Wei & Wu PRD(19)-a1905 [GRB polarization].
@ Gravitational waves: Yao et al a1909 [binary neutron star merger GW170817];
Yang et al a1912 [LIGO-Virgo catalog GWTC-1];
Unnikrishnan & Gillies a2007.
@ Other astrophysics:
Guzzo et al APP(02) [supernova neutrinos];
Freire et al CQG(12)-a1205 [for strongly self-gravitating bodies];
Asvathaman et al MNRAS(16)-a1506
+ news pt(17)jan [supermassive black holes];
Wei et al ApJL(16)-a1601 [using TeV blazars];
Yang & Zhang PRD(16)-a1608,
Zhang & Gong ApJ(17)-a1612 [Crab pulsar and γ];
Wu et al PRD(17)-a1703 [polarized light from astrophysical events];
Wei et al JCAP(17)-a1710 [multimessenger, GW170817 and its electromagnetic counterparts];
Xie PRD(18)-a1807 [astrometry of quasars];
Amorim et al, GRAVITY Collaboration PRL(19)-a1902 [near Sgr A*];
Li et al PRR(20)-a1912 [black-hole shadows];
Li et al a2102 [photon ring].
@ Dark sector: Kesden & Kamionkowski PRD(06)ap [galaxy tidal tails];
Mohapi et al JCAP(16)-a1510,
Bahrami JCAP(19)-a1810 [constraints].
@ CMB: Boucher et al PRD(04)ap [constraints];
Arai et al PRD(16)-a1605 [spectral distortions];
> s.a. cmb.
@ Other cosmology: Amendola & Quercellini PRL(04)ap [large-scale structure];
Bertolami et al GRG(09) [Abell cluster A586];
Hees et al PRD(14)-a1406 [electromagnetic sector];
Creminelli et al JCAP(14)-a1312 [consistency relations for Large Scale Structure];
di Serego Alighieri IJMPD(15)-a1501 [cosmic polarization rotation];
Martins et al JCAP(15)-a1508 [and the stability of the fine-structure constant];
Luo et al JHEA-a1604 [with supercluster Laniakea];
Holanda & Barros PRD(16)-a1606;
Holanda et al CQG(17)-a1705;
Bonvin & Fleury JCAP(18)-a1803;
Bonvin et al a2004 [proposed null test based on galaxy surveys];
Giani & Frion a2005 [lensing time delays].
@ Torsion-balance tests: Schlamminger et al PRL(08) [rotating];
Wagner et al CQG(12)-a1207;
Cowsik et al a1808 [long-period].
@ Atom interferometry:
Fray et al PRL(04);
Dimopoulos et al PRL(07)gq/06;
Giulini a1105-conf [rev];
Wolf et al a1109-proc;
Herrmann et al CQG(12) [rev];
Schlippert et al PRL(14)-a1406
+ news db(14)jun [using Rb and K atoms (different elements), no effect up to 10−7];
Zhou et al PRL(15)-a1503;
Hartwig et al NJP(15)-a1503;
Roura PRL(17)-a1509 [circumventing Heisenberg's uncertainty principle];
Lefèvre et al a1705-proc;
Asenbaum et al a2005 [\(10^{-12}\) level].
@ Other atomic systems:
Peters et al Nat(99)aug [cooled Cs atoms];
Duan et al PRL(16)
[Rb atoms of opposite spin orientation fall at the same rate];
Rosi et al nComm(17)-a1704
+ news sn(17)apr [atoms in superpositions of internal energy eigenstates];
Zhou et al a1904 [Rb atoms].
@ Anti-hydrogen:
Holzscheiter et al PRP(04);
Perez & Sacquin CQG(12) [GBAR experiment];
Doser et al CQG(12) [AEGIS experiment, pulsed cold beam of antihydrogen];
news pw(13)apr [ALPHA experiment at CERN];
Scampoli & Storey MPLA(14) [AEGIS experiment at CERN].
@ Other proposals: Álvarez & Mann PRD(97)gq/96 [lepton and meson sectors];
Wesson IJMPD(05)gq/06 [and higher-dimensional gravity];
Kirch phy/07 [muonium];
Reasenberg & Phillips CQG(10)
+ news po(10)may,
Reasenberg et al CQG(12) [wep, suborbital rocket];
Saha PRD(14)-a1306 [COW test of the weak equivalence principle and spacetime non-commutativity];
Bonder et al PRD(13)-a1305 [with unstable particles];
Hohensee et al PRL(13)-a1303 [radio-frequency spectroscopy];
Kalaydzhyan a1608-conf [relativistic matter in accelerators];
Terno et al a1811 [optical interferometric test proposal].
> Related topics: see Nordtvedt Effect;
radiation [accelerated charge]; self-force [radiation reaction].
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