Workshop on Infrared Modifications of Gravity September 2011

Transcription

1 Workshop on Infrared Modifications of Gravity September 2011 Solar System Tests of Relativistic Gravity: Recent Progress and Possible Future Directions S.G. Turyshev CALTECH U.S.A.

2 Solar System Tests of Relativistic Gravity: Recent Progress and Possible Future Directions Slava G. Turyshev Jet Propulsion Laboratory, California Institute of Technology 4800 Oak Grove Drive, Pasadena, CA USA Workshop on Infrared Modifications of Gravity, The Abdus Salam International Centre for Theoretical Physics, September 2011, Trieste, Italy

3 TESTS OF RELATIVISTIC GRAVITY IN SPACE Outline: Solar System Tests of Gravity The talk will cover: Theoretical Landscape in the 20th Century: (brief ) History of the tests of general relativity Frameworks used: the PPN formalism and Robertson-Mansouri-Sexl Recent progress in the tests of general relativity Beginning of the 21st Century : Motivations for high-precision tests of gravity What to expect in the near future? and some proposed experiments Main objective: Remind where we came from and what lessons we learned Themes for discussion: Are the solar system tests still useful? Is there a discovery potential? Or what is the importance of new improved limits? What tests are most valuable?

4 Theoretical Landscape of the 20 th Century: Competing Theories of Gravity Newton 1686 Poincaré 1890 not a complete list Einstein 1912 Nordstrøm 1912 Nordstrøm 1913 Einstein & Fokker 1914 Einstein 1915 Whitehead 1922 Cartan 1923 Kaluza & Klein 1932 Fierz & Pauli 1939 Birkhoff 1943 Milne 1948 Thiry 1948 Papapetrou 1954 Jordan 1955 Littlewood & Bergmann 1956 Brans & Dicke 1961 Yilmaz 1962 Whitrow & Morduch 1965 Kustaanheimo & Nuotio 1967 Page & Tupper 1968 Bergmann 1968 Deser & Laurent 1968 Nordtvedt 1970 Wagoner 1970 Bollini et al Rosen 1971 Will & Nordtvedt 1972 Ni 1972 Hellings & Nordtvedt 1972 Ni 1973 Yilmaz 1973 Lightman & Lee 1973 Lee, Lightman & Ni 1974 Rosen 1975 Belinfante & Swihart 1975 Lee et al Bekenstein 1977 Barker 1978 Rastall 1979 Coleman 1983 Hehl 1997 Overlooked (20 th century) Theory must be Complete Self-consistent Relativistic

5 Theoretical Landscape of the 20 th Century: Competing Theories of Gravity Newton 1686 Poincaré 1890 Einstein 1912 Nordstrøm 1912 Nordstrøm 1913 Einstein & Fokker 1914 Einstein 1915 Whitehead 1922 Milne 1948 Brans & Dicke 1961 Thiry 1948 Papapetrou 1954 Jordan 1955 Littlewood & Bergmann 1956 Page & Tupper 1968 Bergmann 1968 Deser & Laurent 1968 Nordtvedt 1970 Bollini et al Wagoner 1970 Rosen 1971 Will & Nordtvedt 1972 Ni 1972 Hellings & Nordtvedt 1972 Ni 1973 Yilmaz 1973 Lightman & Lee 1973 Lee, Lightman & Ni 1974 Belinfante & Swihart 1975 Coleman 1983 Cartan 1923 Hehl 1997 Yilmaz 1962 Kaluza & Klein 1932 Rosen 1975 Lee et al Bekenstein 1977 Barker 1978 Rastall 1979 Overlooked (20 th century) Theories that fail already Fierz & Pauli 1939 Birkhoff 1943 Whitrow & Morduch 1965 Kustaanheimo & Nuotio 1967 speed of sound = speed of light

6 Theoretical Landscape of the 20 th Century: Competing Theories of Gravity Newton 1686 Poincaré 1890 Theories that violate the Einstein s Equivalence Principle Einstein 1912 Nordstrøm 1912 Nordstrøm 1913 Einstein & Fokker 1914 Einstein 1915 Whitehead 1922 Milne 1948 Brans & Dicke 1961 Fierz & Pauli 1939 Birkhoff 1943 Thiry 1948 Papapetrou 1954 Jordan 1955 Littlewood & Bergmann 1956 Whitrow & Morduch 1965 Kustaanheimo & Nuotio 1967 Page & Tupper 1968 Bergmann 1968 Deser & Laurent 1968 Nordtvedt 1970 Bollini et al Wagoner 1970 Rosen 1971 Will & Nordtvedt 1972 Ni 1972 Hellings & Nordtvedt 1972 Ni 1973 Yilmaz 1973 Lightman & Lee 1973 Lee, Lightman & Ni 1974 Rosen 1975 Coleman 1983 Cartan 1923 Belinfante & Swihart 1975 Hehl 1997 Yilmaz 1962 Kaluza & Klein 1932 Lee et al Bekenstein 1977 Barker 1978 Rastall 1979 Overlooked (20 th century) Einstein s Equivalence Principle (EEP):

7 Empirical Foundations of General Relativity: Confrontation Between the Theory and Experiment 1e-8 1e-9 1e-10 1e-11 1e-12 1e-13 1e-14 1e-15 1e-16 1e-17 1e-18 Eötvös Tests of Einstein s Equivalence Principle (EEP) Renner Boulder Princeton Moscow Free-Fall LLR Eöt Wash Eöt Wash Eöt Wash MicroSCOPE APOLLO POEM, QUANTUS LLR, APOLLOPLR GG PLR STEP 2040 Uniqueness of Free Fall All bodies fall with the same acceleration WEP SEP

8 Newton 1686 Poincaré 1890 Milne 1948 Belinfante & Swihart 1975 Theoretical Landscape of the 20 th Century: Competing Theories of Gravity Einstein 1912 Nordstrøm 1912 Nordstrøm 1913 Einstein & Fokker 1914 Einstein 1915 Whitehead 1922 Brans & Dicke 1961 Kaluza & Klein 1932 Fierz & Pauli 1939 Birkhoff 1943 Thiry 1948 Papapetrou 1954 Jordan 1955 Littlewood & Bergmann 1956 Whitrow & Morduch 1965 Kustaanheimo & Nuotio 1967 Page & Tupper 1968 Bergmann 1968 Deser & Laurent 1968 Nordtvedt 1970 Wagoner 1970 Bollini et al Rosen 1971 Will & Nordtvedt 1972 Ni 1972 Hellings & Nordtvedt 1972 Ni 1973 Yilmaz 1973 Lightman & Lee 1973 Lee, Lightman & Ni 1974 Rosen 1975 Coleman 1983 Cartan 1923 Hehl 1997 Yilmaz 1962 Theories that violate Local Lorentz Invariance (LLI) Lee et al Bekenstein 1977 Barker 1978 Rastall 1979 Overlooked (20 th century)

9 Empirical Foundations of General Relativity: Confrontation Between the Theory and Experiment 1e-2 1e-4 1e-6 1e-8 1e-10 1e-12 1e-14 1e-16 1e-18 1e-20 1e-22 1e-24 1e-26 Michelson Morley Tests of Local Lorentz Invariance (LLI) JPL Joos TPA Centrifuge Cavities Brillet Hall Hughes Drever NIST Cavities Harvard Washington Fermi GrST Local Lorentz Invariance: Future experiments Test of one-way speed of light:

10 Theoretical Landscape of the 21 st Century: Special Relativity Laboratory tests of Lorentz Invariance: search for preferred-frame effects e.g. CMB laboratory Mansouri & Sexl, 1977 Special Theory of Relativity:

11 Clock comparison experiments: Precision tests of Lorentz Invariance: Theoretical Landscape of the 21 st Century: Special Relativity Michelson-Morley: orientation dependence Kennedy-Thorndike: velocity dependence Ives-Stillwell: contraction, dilation Eisele et al, PRL 103 (2009) Wolf et al, PRL 90 (2003) Saathoff et al, PRL 91 (2003) Tests of isotropy of the speed of light: Herrmann et al, PRD 80 (2009)

12 Newton 1686 Poincaré 1890 Einstein 1912 Whitehead 1922 Cartan 1923 Kaluza & Klein 1932 Fierz & Pauli 1939 Birkhoff 1943 Milne 1948 Brans & Dicke 1961 Page & Tupper 1968 Bollini et al Belinfante & Swihart 1975 Theoretical Landscape of the 20 th Century: Competing Theories of Gravity Nordstrøm 1912 Nordstrøm 1913 Einstein & Fokker 1914 Einstein 1915 Thiry 1948 Papapetrou 1954 Jordan 1955 Littlewood & Bergmann 1956 Kustaanheimo & Nuotio 1967 Bergmann 1968 Deser & Laurent 1968 Nordtvedt 1970 Wagoner 1970 Rosen 1971 Will & Nordtvedt 1972 Ni 1972 Hellings & Nordtvedt 1972 Ni 1973 Yilmaz 1973 Lightman & Lee 1973 Lee, Lightman & Ni 1974 Rosen 1975 Coleman 1983 Lee et al Bekenstein 1977 Barker 1978 Rastall 1979 Hehl 1997 Yilmaz 1962 Whitrow & Morduch 1965 Overlooked (20 th century) Theories that violate Local Position Invariance (LPI)

13 Empirical Foundations of General Relativity: Confrontation Between the Theory and Experiment 1e-1 1e-2 1e-3 1e-4 1e-5 1e-6 1e-7 1e-8 1e-9 Pound Rebka SolS Pound Snider Tests of Local Position Invariance (LPI) R&S SolS R&S Null Redshift H Maser ms Pulsar SolS R&S Saturn Null Redshift Null Redshift Null Redshift ACES BEC Interferometry Gravitational redshift: Local Position Invariance:

14 TESTS OF RELATIVISTIC GRAVITY IN SPACE Parameterized Post-Newtonian (PPN) formalism PPNFormalism:Eddington,Fock,Chandrasekhar,Dicke,Nordtvedt,Thorne,Will, Assumption: Local Lorentz Invariance (LLI) and local position invariance (LPI) hold, thus, preferred frame parameters,, are not included General case, there are 10 PPN parameters: are the Eddington s parameterized post-newtonian (PPN) parameters: Generalrelativity: BransDicketheory: is the post-ppn parameter important for next generation of light propagation tests.

15 TESTS OF RELATIVISTIC GRAVITY IN SPACE PPN Equations of Motion (a part of the model) PossibleEP violation Possible temporal dependence ofg In general theory of relativity, thus (this is not the case for scalar-tensor theories of gravity, for instance, where these parameters can have different values).

16 Newton 1686 Poincaré 1890 Einstein 1912 Whitehead 1922 Cartan 1923 Kaluza & Klein 1932 Fierz & Pauli 1939 Birkhoff 1943 Milne 1948 Thiry 1948 Papapetrou 1954 Jordan 1955 Brans & Dicke 1961 Page & Tupper 1968 Bollini et al Rosen 1971 Belinfante & Swihart 1975 Coleman 1983 Theoretical Landscape of the 20 th Century: Competing Theories of Gravity Yilmaz 1962 Einstein 1915 Whitrow & Morduch 1965 Kustaanheimo & Nuotio 1967 Bergmann 1968 Deser & Laurent 1968 Nordtvedt 1970 Wagoner 1970 Will & Nordtvedt 1972 Theories that predict = 0 or 1 fail Nordstrøm 1912 Nordstrøm 1913 Einstein & Fokker 1914 Hellings & Nordtvedt 1972 Ni 1973 Yilmaz 1973 Lightman & Lee 1973 Lee, Lightman & Ni 1974 Rosen 1975 Hehl 1997 Lee et al Bekenstein 1977 Barker 1978 Rastall 1979 Overlooked (20 th century) Littlewood & Bergmann 1956 Ni 1972 Parameterized Post-Newtonian Formalism (PPN): 2011

17 TESTS OF RELATIVISTIC GRAVITY IN SPACE List of PPN Parameters for Competing Theories Competing theories of Gravity Einstein (1915) GR Scalar Field theories d Einstein (1912) [not GR] * Whitrow-Morduch (1965) * Rosen (1971) 4(1) Papapetrou (1954a, 1954b) Ni (1972) (stratified) Yilmaz (1958, 1962) * Page-Tupper (1968) Nordström (1912, 1913) 1 ½ * Einstein-Fokker (1914) 1 ½ Ni (1972) (flat) 1 1q * Whitrow-Morduch (1960) 1 1q q 0 0* Littlewood (1953), Bergman (1956) 1 ½ *

18 TESTS OF RELATIVISTIC GRAVITY IN SPACE List of PPN Parameters for Competing Theories Competing theories of Gravity Einstein (1915) GR Scalar-Tensor theories Bergmann (1968), Wagoner (1970) Nordtvedt (1970), Bekenstein (1977) Brans-Dicke (1961) Vector-Tensor theories Hellings-Nordtvedt (1973) Will-Nordtvedt (1972) Bimetric theories k 2 Rosen (1975) k Rastall (1979) Lightman-Lee (1973) Stratified theories Lee-Lightman-Ni (1974) ac 0 /c Ni (1973) ac 0 /c 1 bc

19 Theoretical Landscape of the 20 th Century: Competing Theories of Gravity Newton 1686 Poincaré 1890 Einstein 1912 Nordstrøm 1912 Nordstrøm 1913 Einstein & Fokker 1914 Einstein 1915 Whitehead 1922 Cartan 1923 Kaluza & Klein 1932 Fierz & Pauli 1939 Birkhoff 1943 Milne 1948 Thiry 1948 Papapetrou 1954 Jordan 1955 Littlewood & Bergmann 1956 Brans & Dicke 1961 Page & Tupper 1968 Whitrow & Morduch 1965 Kustaanheimo & Nuotio 1967 Bergmann 1968 Deser & Laurent 1968 Nordtvedt 1970 Wagoner 1970 Bollini et al Rosen 1971 Will & Nordtvedt 1972 Ni 1972 Hellings & Nordtvedt 1972 Ni 1973 Yilmaz 1973 Lightman & Lee 1973 Lee, Lightman & Ni 1974 Belinfante & Swihart 1975 Coleman 1983 Yilmaz 1962 Rosen 1975 Lee et al Bekenstein 1977 Barker 1978 Rastall 1979 Hehl 1997 Overlooked (20 th century) Unlikely Scalar-Tensor Theories

20 Theoretical Landscape of the 20 th Century: Competing Theories of Gravity Newton 1686 Poincaré 1890 Einstein 1912 Nordstrøm 1912 Nordstrøm 1913 Einstein & Fokker 1914 Einstein 1915 Whitehead 1922 Cartan 1923 Kaluza & Klein 1932 Fierz & Pauli 1939 Birkhoff 1943 Milne 1948 Thiry 1948 Papapetrou 1954 Jordan 1955 Littlewood & Bergmann 1956 Brans & Dicke 1961 Yilmaz 1962 Whitrow & Morduch 1965 Kustaanheimo & Nuotio 1967 Page & Tupper 1968 Bergmann 1968 Deser & Laurent 1968 Nordtvedt 1970 Bollini et al Wagoner 1970 Rosen 1971 Will & Nordtvedt 1972 Ni 1972 Hellings & Nordtvedt 1972 Ni 1973 Yilmaz 1973 Lightman & Lee 1973 Lee, Lightman & Ni 1974 Belinfante & Swihart 1975 Coleman 1983 Rosen 1975 Lee et al Bekenstein 1977 Barker 1978 Rastall 1979 Hehl 1997 Overlooked (20 th century) Mercury s Perihelion: Theories that fail fromhelioseismology;confirmedbykonoplivetal.,2010

21 Theoretical Landscape of the 20 th Century: Competing Theories of Gravity Newton 1686 Poincaré 1890 Einstein 1912 Nordstrøm 1912 Nordstrøm 1913 Einstein & Fokker 1914 Einstein 1915 Whitehead 1922 Cartan 1923 Kaluza & Klein 1932 Fierz & Pauli 1939 Birkhoff 1943 Milne 1948 Thiry 1948 Papapetrou 1954 Jordan 1955 Littlewood & Bergmann 1956 Brans & Dicke 1961 Yilmaz 1962 Whitrow & Morduch 1965 Kustaanheimo & Nuotio 1967 Page & Tupper 1968 Bergmann 1968 Deser & Laurent 1968 Nordtvedt 1970 Bollini et al Wagoner 1970 Rosen 1971 Will & Nordtvedt 1972 Ni 1972 Hellings & Nordtvedt 1972 Ni 1973 Yilmaz 1973 Lightman & Lee 1973 Lee, Lightman & Ni 1974 Rosen 1975 Belinfante & Swihart 1975 Lee et al Bekenstein 1977 Barker 1978 Rastall 1979 Coleman 1983 Hehl 1997 GW & Binary Pulsar: Theories that fail Overlooked (20 th century)

22 TESTS OF RELATIVISTIC GRAVITY IN SPACE The Current Values of the PPN Parameters Parameter What it measured relative to General Relativity? Current value Effects Experiments Measure of space curvature produced by unit mass Measure of non-linearity in gravitational superposition Measure of existence of preferred location effects Time delay, light deflection Nordtvedt effect, perihelion shift Cassini tracking Lunar laser ranging Earth tides Gravimeter data Measure the existence of preferred frame effects Orbit polarization Lunar laser ranging Spin precession Sun axis' alignment w/ ecliptic Self-acceleration Pulsar spin-down statistics Measure (plus ) of the Binary pulsar failure of conservation laws of energy, momentum and angular momentum Combined PPN bounds acceleration Pulsar: PSR Newton's 3rd law Lunar acceleration Kreuzer experiment

23 Laboratory for Relativistic Gravity Experiments: Our Solar System Strongest gravity potential GM Sun 2 crsun ~ 10 6 GM 2 cr ~ 10 9 Most accessible region for gravity tests in space: ISS, LLR, SLR, free-fliers Technology is available to conduct tests in the immediate solar proximity

24 TESTS OF RELATIVISTIC GRAVITY IN SPACE 40 Years of Solar System Gravity Tests Techniques for Gravity Tests: Radar Ranging:. Laser: Dedicated Gravity Missions: LLR ( on-going!!) New Engineering Discipline Applied General Relativity: UnitCurvature MarsRanging LLR Nonlinearity Cassini 03 1 (2.12.3) AstrometricVLBI 09 GeneralRelativity 4 5 A factor of 100 in 40 years is impressive, but is not enough for the near future!

25 Theoretical Landscape of the 20 th Century: Competing Theories of Gravity Newton 1686 Poincaré 1890 Einstein 1912 Nordstrøm 1912 Nordstrøm 1913 Einstein & Fokker 1914 Einstein 1915 Whitehead 1922 Cartan 1923 Kaluza & Klein 1932 Fierz & Pauli 1939 Birkhoff 1943 Milne 1948 Thiry 1948 Papapetrou 1954 Jordan 1955 Littlewood & Bergmann 1956 Brans & Dicke 1961 Yilmaz 1962 Whitrow & Morduch 1965 Kustaanheimo & Nuotio 1967 Page & Tupper 1968 Bergmann 1968 Deser & Laurent 1968 Nordtvedt 1970 Bollini et al Wagoner 1970 Rosen 1971 Will & Nordtvedt 1972 Ni 1972 Hellings & Nordtvedt 1972 Ni 1973 Yilmaz 1973 Lightman & Lee 1973 Lee, Lightman & Ni 1974 Belinfante & Swihart 1975 Coleman 1983 Hehl 1997 Aesthetics-Based Conclusion for 20 th Century Rosen 1975 Lee et al Bekenstein 1977 Barker 1978 Rastall 1979 Overlooked (20 th century)

26 Theoretical Landscape of the 21 st Century: Competing Theories of Gravity Newton 1686 Poincaré 1890 Einstein 1912 Nordstrøm 1912 Nordstrøm 1913 Einstein & Fokker 1914 Einstein 1915 Whitehead 1922 Cartan 1923 Kaluza & Klein 1932 Fierz & Pauli 1939 Birkhoff 1943 Milne 1948 Thiry 1948 Papapetrou 1954 Jordan 1955 Littlewood & Bergmann 1956 Brans & Dicke 1961 Yilmaz 1962 Whitrow & Morduch 1965 Kustaanheimo & Nuotio 1967 Page & Tupper 1968 Bergmann 1968 Deser & Laurent 1968 Nordtvedt 1970 Bollini et al Wagoner 1970 Rosen 1971 Will & Nordtvedt 1972 Ni 1972 Hellings & Nordtvedt 1972 Ni 1973 Yilmaz 1973 Lightman & Lee 1973 Lee, Lightman & Ni 1974 Belinfante & Swihart 1975 Coleman 1983 Hehl 1997 First decade of 21 st century they are back! Rosen 1975 Lee et al Bekenstein 1977 Barker 1978 Rastall 1979 Overlooked (20 th century) Arkani-Hamed, Dimopoulos & Dvali 2000 Bekenstein 2004 Moffat 2005 Dvali, Gabadadze & Poratti 2003 Multiple f(r) models Scalar-Tensor Theories Bi-Metric Theories Strings theory? Need for new theory of gravity Other challenges Motivations for new tests of GR

27 Theoretical Motivation for New Gravity Tests Long-range massless [or low-mass] scalar: The unit curvature PPN parameter the most important quantity to test

28 TESTING RELATIVISTIC GRAVITY IN SPACE Cassini 2003: Where Do We Go From Here? Cassini Conjunction Experiment: Possible with Existing Technologies?! One needs a dedicated mission to explore accuracies better than 10 6 for both PPN parameters (and ). Interplanetary laser ranging is a possibility.

29 Theoretical Landscape of the 21th Century: Confrontation Between Theory and Experiment 1,7,9 2 3,8 5,6 4,7 1e-5 1e-6 1e-7 1e-8 1e-9 1e-10 Cassini 2002 Gaia BeppiColombo PLR GTDM LATOR, BEACON New Theories & Future Tests 1 Damour-Polyakov-Nordtvedt Damour-Esposito-Farese Damour-Piazza-Veneziano ,6 4,5 7 1e-13 1e-14 1e-15 1e-16 1e-17 1e-18 Eöt Wash, LLR 2007 APOLLO PLR MicroSCOPE POEMS I.C.E. Galileo Galilei STEP 4 Arkani-Dimopoulos-Dvali Dvali-Gabadadze-Poratti F(R) gravity models ,8 2,5,6 7 3,4 1e-12 1e-13 1e-14 1e-15 1e-16 1e-17 LLR 2007 APOLLO PLR 7 Bekenstein Moffat Jaekel-Reynaud 2006 Current best Funded Proposed

30 TESTS OF RELATIVISTIC GRAVITY IN SPACE Conclusions Recent technological progress: arxiv: [gr-qc] Resulted in new instruments with unique performance Could lead to major improvements in the tests of relativistic gravity Already led to a number of recently proposed gravitational experiments Challenges for solar system tests of gravity: Dedicated space-based experiments are very expensive the science must worth the cost EP, G-dot and PPN tests are most relevant. Motivation for the tests in a weak gravity field is a challenge: there is no strong expectation to see deviations from GR in the solar system (we are looking for anomalies ) access to strong(er) gravity regime is needed! GR is very hard to modify, embed, extend or augment (whatever your favorite verb is ) thus, perhaps, those anomalies are important PPN formalism becomes less relevant for modern gravity research Looking to Cosmos for help? There is none: Little or no correspondence between cosmological tests and physical principles in the foundation of tests of PPN gravity EP, LLI, LPI, energy-momentum conservation, etc