g.m. tino, fps-06, lnf, 22/3/2006 atom interferometers and atomic clocks: from ground to space...
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G.M. Tino, FPS-06, LNF, 22/3/2006
Atom Interferometers and Atomic Clocks:Atom Interferometers and Atomic Clocks:From Ground to SpaceFrom Ground to Space
Atom Interferometers and Atomic Clocks:Atom Interferometers and Atomic Clocks:From Ground to SpaceFrom Ground to Space
Università degli Studi di Firenze - Dipartimento di Fisica, LENS
Istituto Nazionale di Fisica Nucleare - Sezione di Firenze
Guglielmo M. TinoGuglielmo M. Tino
G.M. Tino, FPS-06, LNF, 22/3/2006
Laser cooling of atoms
vL L
Lab ref. frame
Atom ref. frame
L(1-v/c) L(1+v/c)
Idea: T.W. Hänsch, A. Schawlow, 1975Exp. demonstration: S. Chu et al., 1985
0
222
2
2 2/8(v) v = - v
[1 ]4 ( )L I IhF
c
Sr MOTLENS, Firenze
G.M. Tino, FPS-06, LNF, 22/3/2006
Laser cooling: temperatures
2
1rB
LM
hk T
c
2DB
hk T
Minimum temperature for Doppler cooling:
Examples: TD Tr
Na 240 K 2.4 KRb 120 K 360 nKCs 120 K 200 nK
Single photon recoil temperature:
Atomic Temperature : kBT = Mv2rms
G.M. Tino, FPS-06, LNF, 22/3/2006
The Nobel Prize in Physics 1997
G.M. Tino, FPS-06, LNF, 22/3/2006
The Nobel Prize in Physics 2001
G.M. Tino, FPS-06, LNF, 22/3/2006
Atom optics
lenses
mirrors
beam-splitters
atom
laser
interferometers
atom
laser
Oven
laser
Atomic beam
atom laser
G.M. Tino, FPS-06, LNF, 22/3/2006
Atom Michelson Interferometer on a Chip Using a Bose-Einstein Condensate
Ying-Ju Wang, Dana Z. Anderson, Victor M. Bright, Eric A. Cornell, Quentin Diot, Tetsuo Kishimoto, Mara Prentiss, R. A. Saravanan, Stephen R. Segal, Saijun Wu, Phys. Rev. Lett. 94, 090405 (2005)
G.M. Tino, FPS-06, LNF, 22/3/2006
Atomic clocksAtomic clocks
G.M. Tino, FPS-06, LNF, 22/3/2006
Accuracy realization of the standard Stability stability of the frequency: depends on of the oscillator
0
0
The measurement of time
OSCILLATOR COUNTER
G.M. Tino, FPS-06, LNF, 22/3/2006
Atomic clocks
.t = 1
The definition of the second
The second is the duration of 9 192 631 770 periods of the radiation corresponding to the transition between the two hyperfine levels of the ground state of the 133Cs atom
(13th CGPM, 1967)
The definition of the second
The second is the duration of 9 192 631 770 periods of the radiation corresponding to the transition between the two hyperfine levels of the ground state of the 133Cs atom
(13th CGPM, 1967)
G.M. Tino, FPS-06, LNF, 22/3/2006
Atomic fountain clock
NIST-F1
G.M. Tino, Firenze, 11/12/2003
G.M. Tino, FPS-06, LNF, 22/3/2006
Cold Atoms Clocks in SpaceCold Atoms Clocks in Space• Interrogate fast (hot) atoms over
long distances T = 10 ms
• Use laser cooled atoms, limitation due to the presence of gravity T = 1 s
• Use laser cooled atoms in microgravity T = 10 s
C. Salomon et al., C.R. Acad. Sci. 2, 1313 (2001)
PHARAO
G.M. Tino, FPS-06, LNF, 22/3/2006
Accuracy of the atomic timeAccuracy of the atomic timeAccuracy of the atomic timeAccuracy of the atomic time
1950 1960 1970 1980 1990 2000 201010-17
1x10-16
10-15
1x10-14
1x10-13
1x10-12
1x10-11
1x10-10
1x10-9
NPL
?
PTB
Optical clocks
NIST
Ca PTB
H MPQ
Cold atoms
Microwave clocksSlope: gain of 10 every 10 years
ACCURACY OF THE ATOMIC TIME
SYRTE
PTBNIST
PTBNRCNBSVNIIFTRI
NPLNBSLSRH
RE
LAT
IVE
AC
CU
RA
CY
YEAR
from C. Salomon
G.M. Tino, FPS-06, LNF, 22/3/2006
Optical clocks: Towards 10-18-10-19
• Direct optical-wave connection by optical frequency comb
• Narrow optical transitions o ~ 1 Hz, 0 ~ 1015 Hz
• Candidate atoms
Trapped ions: Hg+, In+, Sr+, Yb+,…
Cold neutral atoms: H, Ca, Sr, Yb,… (Fermions?)
cycle
0 average fringe
1 1
2y
atom
TNoise
Q Signal CN
Th. Udem et al., Nature 416 , 14 march 2002
G.M. Tino, FPS-06, LNF, 22/3/2006
G.M. Tino, FPS-06, LNF, 22/3/2006
Ca clock example
From L. Hollberg, Hyper symposium 2002
G.M. Tino, FPS-06, LNF, 22/3/2006
• Method: (H. Katori)
Interrogate atoms in optical lattice without frequency shift• Long interaction time• Large atom number (108)• Lamb-Dicke regime
Excellent frequency stability
• Small frequency shifts:• No collisions (fermion)• No recoil effect (confinement below optical wavelength)• Small Zeeman shifts (only nuclear magnetic moments)…
87Sr optical clock
G.M. Tino, FPS-06, LNF, 22/3/2006
Towards a Sr clock – The experiment in Firenze
-400 -200 0 200
0.04
0.06
0.08
0.10
0.12
0.14
0.16
0.18
0.20
87Sr
88Sr
84Sr
86Sr
Laser detuning (MHz)
Flu
ore
sce
nce
sig
na
l (V
)
1S0 - 3P1 (7.5 kHz) 1S0 - 3P0 (1 mHz, 87Sr) 1S0 - 3P2 (0.15 mHz)
Optical trapping in Lamb-Dicke regime with negligible change of clock frequency
• Optical clocks using visible intercombination lines
Firenze 2003, Magneto-optical trapping of all Sr isotopes
Comparison with different ultra-stable clocks(PHARAO/ACES)
PHARAO
G. Ferrari, P.Cancio, R. Drullinger, G. Giusfredi, N. Poli, M. Prevedelli, C. Toninelli and G.M. Tino, Phys. Rev. Lett. 91, 243002 (2003)
G.M. Tino, FPS-06, LNF, 22/3/2006
Atomic clocksAtomic clocks
• Location finding• Precision navigation and navigation in outer space• Variability of Earth’s rotation rate and other periodic
phenomena• Earth’s crustal dynamics• Secure telecommunications
• Very Long Baseline Interferometry (VLBI)• Spectroscopy• Expression of other physical quantities in terms of time• Tests of constancy of fundamental constants• Tests of the special and general theories of relativity
G.M. Tino, FPS-06, LNF, 22/3/2006
Atom InterferometersAtom Interferometers
G.M. Tino, FPS-06, LNF, 22/3/2006
Quantum interference
Initial state
|i
Final state
|f
Interference of transition amplitudesP(|i|f) = |AI + AII|2 = |AI|2 + |AII|2 + 2 Re(AI AII
*)
path II
amplitude AII
path I
amplitude AI
G.M. Tino, FPS-06, LNF, 22/3/2006
Atomic clocks: Interference fringes
G.M. Tino, FPS-06, LNF, 22/3/2006
Time-domain Ramsey-Bordé interferences with cold Ca atoms (PTB)
G.M. Tino, FPS-06, LNF, 22/3/2006
atomic flux at exit port 1 at exit port 2Phase difference
21
Flux
Atom InterferometryAtom Interferometry
Atom interferometer
G.M. Tino, FPS-06, LNF, 22/3/2006
2driftacc Tk
a
a
Ah
m22 at
rot
Matter wave sensors
rotations:
10at
ph
mat 105h
cm~
1711
2
atph
mat 1010v
c~
accelerations:
G.M. Tino, FPS-06, LNF, 22/3/2006
Maximum interaction time : 90 ms3 rotation axes2 acceleration axes
Cycling frequency 2Hz
Expected sensitivity (106 at):• gyroscope : 4 10-8 rad.s-1.Hz-1/2
• accelerometer : 3 10-8 m.s-2.Hz-1/2
50
cm
30 cm
One pair of Raman lasers switched on 3 times
Magneto-Optical Traps
DetectionsLaunching velocity: 2.4 m.s-1
SYRTE cold atom gyroscope
G.M. Tino, FPS-06, LNF, 22/3/2006
Interferometer
MOT 1
15 cm
3 mm
A
PreparationDetection
MOT 2
C. Jentsch, T. Müller, E. Rasel, and W. Ertmer, Gen. Rel. Grav, 36, 2197 (2004)& Adv. At. Mol. Physics
IQO Cold Atom Sagnac Interferometer
G.M. Tino, FPS-06, LNF, 22/3/2006
MAGIA
• Measure g using free falling atoms and atom interferometry
• Add known source masses
• Measure change of g Determine G
g
aM
Misura Accurata di G mediante Interferometria Atomica
G.M. Tino, in “2001: A Relativistic Spacetime Odyssey”, World Scientific (2003)
M. Fattori, G. Lamporesi, T. Petelski, J. Stuhler, G.M. Tino, Phys. Lett. A 318, 184 (2003)
http://www.fi.infn.it/sezione/esperimenti/MAGIA/home.html
G.M. Tino, FPS-06, LNF, 22/3/2006
I
1
2
II
1
2
z1
z2
In collaboration with LNF, Frascati
Misura Accurata di G mediante Interferometria Atomica
http://www.fi.infn.it/sezione/esperimenti/MAGIA/home.html
MAGIA
G.M. Tino, FPS-06, LNF, 22/3/2006
Laser and optical system
Phase locked lasers for Raman transitionsL. Cacciapuoti et al., Rev. Scient. Instr. 76, 053111 (2005)
MAGIA: Firenze atom gravity gradiometer apparatus
Source masses and support
G.M. Tino, FPS-06, LNF, 22/3/2006
MAGIA: first results
G.M. Tino, FPS-06, LNF, 22/3/2006
Precision Measurement of Gravity at Micrometer Scale using Ultracold Sr Atoms
= m g /2 h
optical latticebeam
mirror
probebeam
trappedatoms
CCDcamera
red MOTbeams
g
• G. Ferrari et al., 2006, to be published
G.M. Tino, FPS-06, LNF, 22/3/2006
Test of the gravitational 1/r2 law in the sub-mm range with atom interferometry sensors (Casimir?)
a = 2Gd
Example:
Au 19 g/cm3
d 200 m a 2 x 10-9 ms-2
-d-
95% confidence level constraints on a Yukawa violation of the gravitational inverse-square law. The vertical axis represents the strength of a deviation relative to that of Newtonian gravity while the horizontal axis designates its characteristic range. The yellow region has been excluded (From S. J. Smullin et al., 2005)
• G.M. Tino, in “2001: A Relativistic Spacetime Odyssey”, Firenze, 2001, World Scientific (2003)• G.M. Tino, Nucl. Phys. B 113, 289 (2002)• G. Ferrari et al., 2006, to be published
optical latticebeam
mirror
probebeam
trappedatoms
CCDcamera
red MOTbeams
g
= m g /2 h
G.M. Tino, FPS-06, LNF, 22/3/2006
From Earth Laboratories to SpaceFrom Earth Laboratories to Space
G.M. Tino, FPS-06, LNF, 22/3/2006
Atomic Clock Ensemble in SpaceAtomic Clock Ensemble in Space
PHARAO : Cold Atom Clock in Space. CNES (France)
A. Clairon, P. Laurent, P. Lemonde, M. Abgrall, S. Zhang, C. Mandache, F. Allard, M. Maximovic, F. Pereira, G. Santarelli, Y. Sortais, S. Bize, H. Marion, D. Calonico, (BNM-LPTF), N. Dimarcq (LHA), C. Salomon (ENS)
SHM : Space Hydrogen Maser. ON (Switzerland)
L. Jornod, D. Goujon, L.G. Bernier, P. Thomann, G. Busca
MWL : Microwave link. Kayser-Threde-Timetech (Germany)
W. Schaefer, S. Bedrich
ACES is open to any interested scientific userW. Knabe, P. Wolf, L. Blanchet, P. Teyssandier, P. Uhrich, A. SpalliciNew members :2001: UWA (Australia), A. Luiten, M. Tobar, J. Hartnett, R. Kovacich2002: LENS (Italy), G.M. Tino, G. Ferrari, L. Cacciapuoti
ESA: MSMStephen Feltham CNES:C. Sirmain + team of 20 engineers at CST, Toulouse
Support: ESA, CNES, BNM, CNRS
• A cold atom clock in space• Worldwide access• Fundamental physics tests
H= 400 kmV=7 km/sT= 5400 s
G.M. Tino, FPS-06, LNF, 22/3/2006
ACES ON COLUMBUS EXTERNAL ACES ON COLUMBUS EXTERNAL PLATFORMPLATFORM
ACES ON COLUMBUS EXTERNAL ACES ON COLUMBUS EXTERNAL PLATFORMPLATFORM
M = 227 kg P = 450 W
Launch date : 2009Mission duration : 18 months
ACES
G.M. Tino, FPS-06, LNF, 22/3/2006
ACES objectives
L. Blanchet, C. Salomon, P. Teyssandier, and P. Wolf, A&A 370, 320 (2001)
G.M. Tino, FPS-06, LNF, 22/3/2006
ESA-AO-2004Life and Physical Sciences and Applied Research Projects
G.M. Tino, FPS-06, LNF, 22/3/2006
PARCSPrimary Atomic Reference Clock in Space
G.M. Tino, FPS-06, LNF, 22/3/2006
HYPER
Differential measurement between two atom gyroscopes and a star tracker orbiting around the Earth
~h/mImproving knowledge offine-structure constant
Mapping Lense-Thirring effect close to the Earth
Atomic gyroscope control of a satellite
Testing EP with microscopic bodies
http://sci.esa.int/home/hyper/index.cfm
G.M. Tino, FPS-06, LNF, 22/3/2006
ESA-AO-2004 AI
G.M. Tino, FPS-06, LNF, 22/3/2006
Laser Cooled Atom (LCA) Sensor
for Ultra-High-Accuracy Gravitational Acceleration
and Rotation Measurements
in response to ESA ITT No. AO-1-4477/03/NL/CH
G.M. Tino, FPS-06, LNF, 22/3/2006
Prototype field ready sensor
Laser system
Sensor optomechanicsSensor head
From M. Kasevich talk atSpacePart '03 Conference Washington D.C., December 10th - 12th, 2003.
W.W. Hansen Experimental Physics Laboratory, Stanford, CA 94305
SpacePart ‘03
G.M. Tino, FPS-06, LNF, 22/3/2006
JPL
http://horology.jpl.nasa.gov/quantum/atominterferometry.html
G.M. Tino, FPS-06, LNF, 22/3/2006
BEC in space
G.M. Tino, FPS-06, LNF, 22/3/2006
pumps
µ-metal shielding
Battery pack
Laser
DC-DC transformer
Computer control
From E. Rasel, 2005
G.M. Tino, FPS-06, LNF, 22/3/2006
G.M. Tino, FPS-06, LNF, 22/3/2006
Applications of new quantum sensors based on atom interferometry
• Development of transportable atom interferometers
• Short-distances forces measurement
• Test of equivalence principle
space
• New detectors for gravitational waves ? geophysics
• Search for electron-proton charge inequality
• New definition of kg
• Measurement of fundamental constants G
G.M. Tino, FPS-06, LNF, 22/3/2006
Future prospects:Atomic clocks
• New optical clocks with fractional stability ~ 10-17-10-19
• mm-scale positioning and long-distance clock syncronization
• Very large baseline interferometry (VLBI) and geodesy
• Search for variation of fundamental constants
• Tests of SR and GR in Earth orbit (ACES, OPTIS)
• Improved tests of GR in solar orbit: Shapiro delay, red shift, …
G.M. Tino, FPS-06, LNF, 22/3/2006
Conclusions
• New atomic quantum devices can be developped with unprecedented sensitivity New atomic quantum devices can be developped with unprecedented sensitivity using ultracold atoms and atom opticsusing ultracold atoms and atom optics
• Applications: Fundamental physics, Earth science, Space research, CommercialApplications: Fundamental physics, Earth science, Space research, Commercial
• Well developped laboratory prototypesWell developped laboratory prototypes
• Work in progress for transportable/space-compatible systemsWork in progress for transportable/space-compatible systems
G.M. Tino, FPS-06, LNF, 22/3/2006
Fine
G.M. Tino, FPS-06, LNF, 22/3/2006
LINKS
G.M. Tino, FPS-06, LNF, 22/3/2006
h/m and fine structure constant
S. Chu et al., 2002
G.M. Tino, FPS-06, LNF, 22/3/2006
vgmUI
Goal: Redefinition of kg on microscopic quantities with accuracy better than 10-8
Idea: Watt-balance compares electrical and mechanical realization of Watt
ztU
vmgz
I
Watt balance groups working at NPL (UK), NIST (USA), METAS (Switzerland), BNM (France)
The kilogram is the unit of mass; it is equal to the mass of the international prototype of the kilogram (1st CGPM, 1889)
The kilogram is the unit of mass; it is equal to the mass of the international prototype of the kilogram (1st CGPM, 1889)
Unit of mass
G.M. Tino, FPS-06, LNF, 22/3/2006
Tests of weak equivalence principle
Best tests so far: EOT-Wash group (Adelberger, Gundlach), See “http://www.npl.washington.edu/eotwash/”Long range EP tested at the level of 10-13
Atoms:
Prospects
• different isotopes, e.g. 85Rb vs 87Rb • different atoms, e.g. Rb vs Cs • bosons vs fermions, e.g. Rb vs 40K • different spins • anti-matter (?)
Space: MICROSCOPE 10-15
STEP 10-18
Fray S, et al. PRL. 93, 240404 (2004)g/g=(0.4+/-1.2)x10-7( )
10-12 - 10-13
G.M. Tino, FPS-06, LNF, 22/3/2006
Test of equivalence principle for anti-matter
H• Compare g
g/g 10-9 ?
- Time of flight
- Atom interferometry • Raman transitions between 2S HFS sublevels
• 2Shigh-P levels transitions (T. Heupel et al., Europhys. Lett. 57, 158 (2002))
H
anti-H production (ATHENA, ATRAP)
anti-H selective state population
anti-H cooling
anti-H trapping
g measurement:
• Steps:
1s1/2
2s1/2 2p
243 nm
121.6 nm
243 nm
1/2
3/2
1420 MHz
0
1
0
1
177 MHz
3s1/2 3p
4 45 5
H levelspartial scheme(not to scale)
1/23/2
10968 MHz
59 MHz
24 MHz
g/g 10-3 ?
G.M. Tino, FPS-06, LNF, 22/3/2006
Search for electron-proton charge inequality
• Electrostatic, ferromagnetic, diamagnetic levitation Millikan (1935), Morpurgo (1966-1984), Braginsky (1970), Stover (1967), Rank (1968), LaRue (1979)
• Gas flow Piccard and Kessler (1925), Hillas & Cranshaw (1960), King (1960)
• Acoustic cavity Dylla and King (1973)
• Atomic and molecolar beams Hughes (1957), Chamberlain & Hughes (1963), Fraser (1965), Shapiro (1957), Shull (1967)
Present limit ep< 1x10-21 e
(From G. Carugno and G. Ruoso)
G.M. Tino, FPS-06, LNF, 22/3/2006
Chiu - Hoffmann (1964)Indipendenza della carica dell’elettrone dalla velocità e trasformazioni di Lorentz
Con atomi di vario Z miglioro limite
Neutralità materia
Einstein (1929)Spiegare campi magnetici terra e sole ep+ rotazione -> i -> B si aspettava ep= 3x10-19 e
ep= qe+ qp; qn ; q
Bondi - Lyttleton (1959); Hoyle (1960)se ep~ 2x10-18 e => espansione universo
Feinberg - Goldhaber (1959); Gell-Mann - Nambu (1960)
ep ≠ 0 per spiegare leggi di conservazione (es. numero barionico)
Motivazioni: digressione storica
Limiti su qn e q
Se C e CPT conservati da qn = qe + qp + qricavo limiti
Attualmenteqn < 10-21 e Esp. con fasci di neutroni termici (1988)
q < 10-15 e Da astrofisica, Barbiellini - Cocconi (1987)
qe (v) qe (0)[1 a(v /c)2]
(Da G. Carugno and G. Ruoso)
G.M. Tino, FPS-06, LNF, 22/3/2006
Search for electron-proton charge inequality
ep< 1x10-25 e ?
G.M. Tino, FPS-06, LNF, 22/3/2006
Gravitational wave detection by atom interferometry
Presentation at 2004 Aspen Winter College on Gravitational Waves:See http://www.ligo.caltech.edu/LIGO_web/Aspen2004/pdf/vetrano.pdf
See also: Chiao RY, Speliotopoulos AD, J. Mod. Opt. 51, 861 (2004)A. Roura, D.R. Brill, B.L. Hu, C.W. Misner, gr-qc/0409002
1E-3 0,01 0,1 1 10 100 1000 100001E-24
1E-23
1E-22
1E-21
1E-20
1E-19
1E-18
1E-17
1E-16
h (1
/Sqr
t(Hz)
)
/2 (Hz)
Virgo
G.M. Tino, FPS-06, LNF, 22/3/2006
LMXRBs&
Perturbed“newborn”NS
SlowPulsars
(1 y)
Sources - Detectors
-24
-22
-20
-18
h [1/sqrt Hz]
f [Hz] - 4 - 2 0 2 4
10 10 10 10 10
Galactic binaries
Coalescence ofmassive BH
NS-NS andBH-BH Coalescence
SN corecollapse
msPulsars
(1 y)
12
3
1 LISA2 LIGO – Virgo3 A.I.
G.M. Tino, FPS-06, LNF, 22/3/2006
Gravimeters
Comparison between instruments Spring gravimeter(1) Optical interferometry
dropping gravimeter(2,3) Superconducting
gravimeter(3,4) Atom interferometry
gravimeter(5)
Resolution g/g
5 x 10-9
only for short periods and distances
1 x 10-8/Hz
1 x 10-8/Hz
2 x 10-8 in 1.3 s
Accuracy g/g Or Repeatibility
0.5 x 10-6
only for short periods and distances
4 x 10-9
1 x 10-9
1 x 10-9
Measurement
Relative
Absolute
Relative
Absolute
Size and Weight
21.5 x 22 x 31 cm 9 kg
1.5 m3 320 kg
No field operation estimated 1 m3
250 kg
Error sources
temperature and random drift
Clibration varies in time and with position
magnetic and
electrostatic effects
thermal drift magnetic and
electrostatic effects
?
(1) www.LaCosteRomberg.com (2) www.microgsolutions.com (3)O. Francis, T.M. Niebauer, G. Sasagawa, F. Klopping, and G. Gschwind, “Calibration of a superconducting gravimeter by comparison with an absolute gravimeter FG5 in Boulder”, Geoph. Res. Lett.25 (1998) 1075-1078. (4) J.M. Goodkind “The superconducting gravimeter”, Rev. Scient. Instr., 70 (1999) 4131-4152. (5) A. Peters, K.Y. Chung, and S. Chu “Measurement of gravitational acceleration by dropping atoms”, 400 (1999) 849-852.
Resolution: 3x10-9 g after 1 minute
Absolute accuracy: g/g<3x10-9
A. Peters, K.Y. Chung and S. Chu, Nature 400, 849 (1999)
G.M. Tino, FPS-06, LNF, 22/3/2006
Gravimeter application in geophysics
Gravimetric measurements at Etna Pizzi DeNeri site during a 48-h-long period encompassing the beginning of the 2002-2003 eruption (Branca et al. Geoph. Res. Lett. 30 2077 (2003))
G.M. Tino, FPS-06, LNF, 22/3/2006
Gravimeter Application
Geophysical researchMonitoring of magma migration in active volcanic areasDetection of vertical crustal motion in seismogenic areasPost glacial rebound studiesMeasuring uplift in subduction areasEarthquake (strain accumulation in tectonic areas during interseismic phase)Calibrating measurement made by other techniques: height measurements, relative gravimeter
Environmental monitoringWater table monitoring in deep and/or multiple acquifersMonitoring of mining effectSlope and earth fill dam stabilityGlobal sea level studies for earth warming assessmentOn site inspection of sites for nuclear test or else.
Mineral exploration
G.M. Tino, FPS-06, LNF, 22/3/2006
Gradiometer applications
Airborne gravity measurement for oil and mineral exploration hazard investigation
Satellite gravity meausrement : GOCE projectGRACE Project
Gravity gradiometry gives higher resolution inMonitoring of anomaliesData processingJoint gravimetric-seismological data inversion
Gradiometer based on absolute Gravimeter combines complementary range of sensitivity for different mass/distance source
Tensorometer
G.M. Tino, FPS-06, LNF, 22/3/2006
ACES: Relativity tests
G.M. Tino, FPS-06, LNF, 22/3/2006
Search for variation of
G.M. Tino, FPS-06, LNF, 22/3/2006
Search for variation of