1. Tachyons: Messengers from the future?
Robert Ehrlich
George Mason University

2. Unfortunate uses of the word "tachyon“
(nothing to do with this talk)
tachyon healing, tachyon rods
tachyon energy, tachyon beads
tachyon chambers, tachyon boots
tachyon wellness, tachyon EMF protection
tachyon superfoods, tachyon gunCams
tachyon meditation, tachyon wristbands
tachyon illumination, tachyon belts
tachyon jewelry, tachyon binoculars
tachyonized material testing, tachyon cameras
tachyon skin care, tachyon star dust
and:  Tachyonized Personal Sexual Enhancement 
Tachyon ahead

3. Link between faster-than-light speed and time travel
There was a young lady named Bright Whose speed was far faster than light; She set out one day In a relative way And returned on the previous night.
A. H. Reginald Butler

4. “Faster-than-light speeds have no possibility of existence.”
If they did exist a beam of FTL particles could send a message back to the past – the “tachyon anti-telephone”
Could Einstein have been wrong about no FTL speed?

5. Basics of relativity (1905)
Based on 2 ideas:
Same laws of physics for all observers
Same speed of light in vacuum for all observers
All sorts of weird conclusions follow
Time is the fourth dimension
Slowing down of “moving” clocks
No absolute motion
“Relativity of simultaneity”
Time order of events can get scrambled
One type of time travel is definitely possible

6. One way to reach FTL speed that does not work
Just keep accelerating ship at “1 g” for about a year to reach light speed?
It does not work because relativity says mass increases with speed
It takes an infinite amount of energy to reach light speed

7. Nothing can go faster than light
… if it travels in in vacuum
… if it carries energy or information
… if it started out slower than light

8. spukhafte Fernwirkung!
Quantum Entanglement of 2 particles
spukhafte Fernwirkung!
Information about their quantum states are so inextricably linked that finding the color of one particle can tell you about the other instantly.
Does this permit FTL communication? No!

9. A “loophole” in relativity to allow FTL?
Energy
m is imaginary!
Bilaniuk, O.-M. P.; Deshpande, V. K.; Sudarshan, E. C. G. "'Meta' Relativity". American Journal of Physics (1962).

10. Hypothetical FTL particles (“tachyons”)
Tachyons are consistent with equations of relativity
They can never slow down below speed of light
Imaginary mass means as they lose energy the speed up!?!
Light speed is a two-way barrier
3 classes of particles: tachyons, tardyons & luxons
Tachyons looked for but not yet found
Their existence is unknown – most physicists dubious
Neutrinos are the only known possibility

11. Neutrinos: the most “ghostly” subatomic particles known

12. Neutrinos Very weakly interacting
Can pass through a lightyear of lead without being absorbed
Trillions passing through your finger-tip each second
Mass believed to be no more than 2 millionths that of the electron
They are emitted during radioactivity (beta decay)
Example of beta decay

13. Why are neutrinos the only tachyon candidate?
Only neutrinos have masses so close to zero that within experimental uncertainty we do not know if mass is real or imaginary
Measured value of m2 X
Doing experiments with neutrinos is really hard

14. Super-Kamiokande Neutrino detector: Currently the World’s largest
Need Huge detectors
Shield against all “backgrounds”
Want intense sources
Be patient

15. How to tell if neutrinos are tachyons?
See if a beam of neutrinos can outrace photons over some distance
See if high energy neutrinos take longer to travel a known distance than low energy neutrinos
Measure their m2 and see if it is negative
Four additional more technical ways

16. Using TOF to measure speed of neutrinos
2011 claim that beam of neutrinos outraced light
732 km
Oops – they found a loose cable in the timing circuit!
Corrected result: Neutrino speed no different than light within uncertainties
This need not mean they do not exist

17. Need a more sensitive speed measurement
Look at neutrinos from a very short “burst” occurring a long distance away
Could use an atomic bomb …. But…
No very short bursts from the sun
Look at the neutrino burst from a supernova, but these are quite rare in our galaxy

18. Supernova: the death of a massive star

19. Supernova SN 1987A Only Neutrino “burst” ever seen Visible burst
Last one seen was in 1604 AD
Only Neutrino “burst” ever seen
Visible burst

20. My “3+3” tachyon model
In 2013 using data from SN 1987A I published a model claiming 3 neutrino masses one of which was a tachyon
Very much against the conventional thinking
Subsequently various kinds of evidence has been published in support of the model
An experiment now underway at the Karlseruhe Institute of technology (KIT) known as KATRIN will pronounce the ultimate verdict

21. KATRIN experiment spectrometer en route to KIT

22. KATRIN experiment to measure neutrino mass Cannot put subatomic particles on a scale!
Count how many electrons emitted with different energy in beta decay
Started taking data in March 2019
Nearly everyone expects to find m < 1 eV
My “3+3” model says they will find 3 much larger masses one of which is imaginary (a tachyon)
First results from experiment ambiguous -- enough data within a year to tell

23. Tachyons and messages from the future
A message claiming to be from my future self: “Do not post those nude photos from the other night!”

24. Psychic abilities? Precognition
Claimed ability to receive messages from the future
Not necessarily a “psychic” ability
Possibilities:
Phenomenon does not exist
Only certain gifted people can receive messages
Only occurs in extreme cases, e.g., a premonition of disaster
Signal is small & hidden by the noise
Technology for receiving messages does not yet exist
The technology exists but we are unaware how to use it
“Feeling the future: A meta-analysis of 90 experiments
on the anomalous anticipation of random future events” (2015)
Daryl Bem, Patrizio Tressoldi, Thomas Rabeyron, and Michael Duggan
Psychic abilities?

25. A Review of this talk
FTL speed is connected with time travel and backward time messaging Einstein (and most physicists today) believe there are no FTL particles known as tachyons If tachyons exist neutrinos are the only candidates I have a model making a specific testable prediction about neutrinos being tachyons The KATRIN experiment now underway should decide within a year Tachyons raise the possibility of sending messages back in time

26. Sending messages back in time Questions to ponder
If you got a message claiming to be from your future self, what would it take for you to believe it was real?
Have you ever gotten a message from the future including a premonition that came true?
What about the “grandfather paradox?”
If FTL tachyons exist does that mean you could travel at FTL speed and travel to the past? This is the subject for another talk!