# C. S. Unnikrishnan Gravitation Lab,

## Presentation on theme: "C. S. Unnikrishnan Gravitation Lab,"— Presentation transcript:

Dynamics, Relativity and the Equivalence Principle in the ‘once-given’ Universe
C. S. Unnikrishnan Gravitation Lab, Tata Institute of Fundamental Research, Homi Bhabha Road, Mumbai , India address: Website:

Topics: Experimental tests of the PREDICTIONS of the General Theory of Relativity Experimental tests of the FOUNDATIONS of the General Theory of Relativity: Equivalence Principles and Special Relativity SOME missing physics Implications for the General Theory of Relativity

Testing The General Relativistic Theory of Gravity
Tests of ‘electric gravity’: Redshift, Time dilation, Deflection, Shapiro delay Tests of Gravitomagnetism: Lense-Thirring and Geodetic spin precession Gravitational waves

Equivalence Principle
Universality of Free Fall  Weak Equivalence Principle; Universal ratio of gravitational and inertial mass Einstein’s Equivalence Statement: Gravitational field ‘g’ and acceleration ’-a=g’ are equivalent g

Einstein Equivalence Principle
g From gravitational redshift to time dilation: Frequency is the number of waves ‘per second’. The number detected is the same as the number of waves emitted at the source – however, the unit ‘second’ is different at different points in these frames and hence the measured frequency is different.

The real gravitational field near the earth
Gravitomagnetism : uniquely relativistic consequence of GR-like theories The real gravitational field near the earth

Testing Foundations The Weak Equivalence Principle (WEP) Einstein Equivalence Principle and the Strong Equivalence Principle The Principle of Relativity Dynamics: The Special Theory of Relativity

A serious problem with the foundations of fundamental theories
Universe with all its matter content and gravity existed ages before we started making our theories… All our fundamental theories of the physical world were completed well before we acquired ANY significant knowledge about the physical universe, its content and its long term evolution. In particular, the theories of relativity and dynamics (including QM) as well as the theory of gravity were developed assuming an EMPTY universe. However, the gravitational potentials of the matter in the universe is a billion (109) times larger than our local potentials, and if these have any say in dynamics, then we have completely missed that out in our theories. All our experimental tests, in contrast, are in the unavoidable presence of cosmic gravity. So, empirical evidence includes all cosmic gravitational effects, whereas fundamental theories, as constructed, do not – A reconsideration becomes essential.

300 Million Light years (up to Coma) 10 Billion Light years

Moving through the Universe and its CMB marker
Absolute velocity Absolute (universal) time Same as average T (1/105) Every observer can decide whether he is moving or not, and all clocks in the universe can be synchronized to this temperature.

There is ONE special frame in which V=0 In all other frames, SPACE is anisotropic in the frame of a moving observer. There is a large current of matter (the charge of gravity)

Isotropic space remains isotropic after Lorentz transformations on coordinates
Clear conflict with real anisotropic space from matter current A physical and logically consistent boost transformation should have returned an anisotropic homogenous metric, reflecting the symmetry of the transformed space.

A maximal Lorentz violation from a vector-like (part of a modified metric tensor field) generated by the motion of the laboratory through the real matter-filled universe. The anisotropic current and the gravi-magnetic potentials are physical and large ~v/c. Physics – dynamics and relativity – indeed has a preferred frame and universal time. There are important consequences for even laboratory experiments

In a frame moving through this matter filled universe, there is a large matter-current and space is ANISOTROPIC Galilean boost gives the physically consistent metric – flat and anisotropic

Both time dilation and length contraction follows from this anisotropic transformed metric, with ‘absolute velocity’ (velocity relative to the cosmic frame) in the Lorentz factors instead of relative velocities. GPS/atomic clock data strongly support time dilations with ‘absolute’ velocities. It is in fact the most accurate estimates of such time dilations.

300 Million Light years (up to Coma) 10 Billion Light years

Dynamics and Relativity from Cosmic Gravity (Cosmic Relativity)
Principle of Relativity as unobservability of this ‘gauge’ potential. Same as statement of Lorentz/Galileo Invariance or invariance under boosts. NEWTON’S LAW FROM COSMIC GRAVITY It is already relativistic and ‘gravito-magnetic’

NEWTON’S LAW FROM COSMIC GRAVITY
It is relativistic and ‘gravito-magnetic’ EQUIVALENCE PRINCIPLE FROM COSMIC GRAVITY If dynamics respects Newton’s law it respects Equivalence principle as well! The result that Newton’s law of motion and the WEP have exactly the same cosmic gravitational origin and physical content implies that all test systems that follow Newton’s law in any experiment (even in non-gravitational fields) also obeys the WEP, to the same accuracy! C. S. Unnikrishnan, Int. Jl. Mod. Phys. (2014) WAG 2014

A very serious prediction:
No differential time dilation in accelerated frames!

10 m This test will return a positive result, obeying EEP – There will be a redshift in an accelerated frame, as there is in a real gravitational field.

10 m However, this test will return a null result, violating EEP – There will be no differential time dilation in an accelerated frame, while there is, in a real gravitational field. But the test is intermingled with the issue of the nature of the relative velocity of light and clock synchronization. Galilean relative velocity of light is the only way one can get a redshift and no differential time dilation.

Galilean or Einsteinien?
Is the genuine one-way velocity of light relative to an inertial observer Galilean or Einsteinien?

Is light Galilean or Einsteinien?
The Michelson-Morley interferometer experiment compared the TWO-WAY speed of light in two orthogonal directions

Time delay (fixed L in rest frame) Vel. of reference source/detector

The relative one-way velocity of light is Galilean to first order

Universe in rotating frame
Cosmic Gravito-magnetic Effects Universe in rotating frame Currents of mass generates a vector potential. ‘A’ changes direction… Centrifugal force is clearly of cosmic gravitational origin (Mach, Sciama…)

Universe in rotating frame
Cosmic Gravito-magnetic Effects Universe in rotating frame Currents of mass generate large vector potential And its ‘curl’ is a strong gravito-magnetic field

In the interferometer frame: Mass current with curl  Gravitomagnetic field

Atom Interferometer Gyroscope and Cosmic Gravity

Cosmic Gravity and Spin Physics
SPIN (both classical and quantum) will couple to this because spin and angular momentum are currents of the charge of gravity – mass currents Results: Spin-Statistics Connection Spin valves in chiral molecules (experiments) Fractional quantum Hall effect Geometric Phases in chiral transport (experiments) Unnikrishnan: Relativity and Dynamics in the once-given Universe (in prep.)

An Ampere Experiment in Electromagnetism
The flip of the magnetic moment is due to a reversed current-current interaction or reversed magnetic field, now written as

An ‘Ampere Experiment’ in Gravity

Einstein’s equation is INCOMPLETE and needs an important correction.
All our theories are constructed and TESTED in the background gravity of the entire matter in the universe. There are no experimental tests in the absence of this cosmic gravity, and there will not be any that can avoid it. Therefore, ALL theories have to incorporate this EVER-PRESENT gravitational background a priori, in the relevant equation itself. Einstein’s equation is INCOMPLETE and needs an important correction. Warning: Removal gives the wrong theory This incorporates Mach’s principle, and more, into theory of gravity It is now clear why Einstein could not do it, as he regretted, before ‘seeing’ the real universe. 35

The Centenary Einstein Equation
Machian, Galilean, and fully relativistic The only input is the observed ~isotropic and ~homogeneous universe with near-critical density No assumptions of relativity principle, equivalence principle, or geodesic principle – all are derived from cosmic relativity. On close and careful experimental scrutiny, special relativity has to be replaced by cosmic relativity as the only consistent choice for the basis of GR.

The case of the asymmetric clocks:
V Time contraction for leftward clock! Experiments do show that the relative rate of clocks depend not on their relative velocity, but on their absolute velocity (GPS data).

Is light Galilean or Einsteinien?
The Michelson-Morley interferometer experiment compared the TWO-WAY speed of light in two orthogonal directions

NO SIGNAL WAS SEEN Lorentz-Fitzgerald: There is ether, as a special preferred frame Anisotropic length contraction, anisotropic speed-of-light Einstein: There is no ether, no real length contraction and no preferred frame, but isotropic speed of light