Searching for LV in the gravitational

field

Jay D. Tasson

Carleton College

outline

• basics – a Newtonian example

• a few comments on General Relativity

• constructing the post-Newtonian framework

• experiments

Quentin Bailey, Alan Kostelecky PRD 2006

Newtonian exampleQ: what does it mean to have Lorentz violation in the

gravitational field?

~F

(Not to scale)

a) The force changes when you

rotate the observer.

b) The force changes when you

rotate the tennis ball

c) The force changes when you

rotate the Earth and the tennis

ball about a common axis

d) The force changes when you

rotate the Earth

e) None of the above

Newtonian exampleQ: what does it mean to have Lorentz violation in the

gravitational field?

~F

(Not to scale)

a) The force changes when you

rotate the observer.

b) The force changes when you

rotate the tennis ball

c) The force changes when you

rotate the Earth and the tennis

ball about a common axis

d) The force changes when you

rotate the Earth

e) None of the above

~F =m~g

Newtonian exampleQ: what does it mean to have Lorentz violation in the

gravitational field?

~F

(Not to scale)

a) The force changes when you

rotate the observer.

b) The force changes when you

rotate the tennis ball

c) The force changes when you

rotate the Earth and the tennis

ball about a common axis

d) The force changes when you

rotate the Earth

e) None of the above

~F =m~g(1+LV )

Sun-centered frame

lunar laser ranging

binary pulsar

perihelion shift of planets

gyroscope experiment

light propagation

gravimeter tests

torsion-pendulum tests

Gravitational experiments

Newtonian exampleQ: How can you measure s?

~F

(Not to scale)

~F =m~g(1¡ 112sXY sin

2 Â sin(2!T +2Ã) + : : :)

ongoing searches with...

proposals based on: Bailey, Kostelecky, PRD ’06

Bailey, PRD ’09

• solar-system tests Battat, Chandler, Stubbs, PRL ’07

• gravimeters Mueller et al., PRL ’08

(atom interferometer) Chung et al., PRD ’09

• laboratory gravity Long, in CPT 10

• binary pulsars

• gyroscope

• light travel

LLV =Lfermion+Lphoton+Lpuregravity+ : : :

PPN vs. SME

framework PPN SME

parameterizes

deviations from:

General Relativity

(including some

Lorentz violation)

exact Lorentz invariance

(including some

corrections to GR)

expansion about: GR metric GR + standard model

lagrangian

GR corrections? Yes Yes, different ones!

matter sector

/standard model

corrections?

No Yes

Lorentz invariant

corrections?

Yes (not primary interest)

parameterized deviations from GR are different!

Example: pure-gravity sector of minimal SME vs. PPN

• different coefficients

• can lead to qualitatively different results

If you currently investigate the PPN,

you may be able to test additional

physics using the SME!

Bailey, Kostelecky, PRD ’06