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3 votes

Please help me with this paradox

The recession rates you are talking about are not relative velocities, so it's not meaningful to compare them to the speed of light, and it's incorrect to use them to calculate relativistic effects. ...
Sten's user avatar
  • 5,717
6 votes

Could a delayed choice Aharonov-Bohm experiment be used for FTL information transfer?

A transient electromagnetic wave will propagate outward from the solenoid when you change the field. Electron pairs before it passes will show the old phase shift, and electron pairs after it passes ...
benrg's user avatar
  • 27.3k
2 votes

Whats wrong with concept of "faster than light" information transfer device? (not about technical implementation, just about theory)

There isn't enough information given here to answer this question fully, but the short version is that whatever you do at you do for the "modulation" has absolutely no observable effect on ...
ors's user avatar
  • 289
5 votes
Accepted

Could a delayed choice Aharonov-Bohm experiment be used for FTL information transfer?

I looked at the segment you mention where Maudlin discusses this. It precisely corresponds to an experimental proposal made by Zeilinger in 1984 (i.e. 40 years ago). The technical difficulty was ...
DrChinese's user avatar
  • 1,419
2 votes
Accepted

If the speed of causality changes, could you go FTL?

What you are describing as a "causality change" is simply the concept of a metric in general relativity. Having a metric on a spacetime is equivalent if you want to the assignment of a light ...
Pipe's user avatar
  • 813
1 vote

If the speed of causality changes, could you go FTL?

In special relativity, one cannot simply use the regular three-dimensional velocity $v$. Instead, one has to use the four-velocity $u^\mu = \frac{dx^\mu}{d\tau}$ where $\tau = t\sqrt{1-\frac{v^2}{c^2}}...
paulina's user avatar
  • 1,301
2 votes

Transmitting Data faster than the speed of light using entangled particles

It's not that simple. Entanglement is a quantum phenomenon in whcih you have the complete knowledge about the combined system of the particles, but still have no information about its individual parts....
Ronny's user avatar
  • 166
0 votes

Does the fact that we are able to see CMBR implies that universe expanded faster than light?

Although another answer accurate points out that we don't see radiation from arbitrarily early times, we could in principle without violating relativity. For example, the possibility has been ...
Sten's user avatar
  • 5,717
1 vote

Does the fact that we are able to see CMBR implies that universe expanded faster than light?

No, the fact that we see the CMB simply means that the radius of the observervable universe is at least 13 billion light years. If you imagine the early universe as a 3D infinite sea of bright orange ...
RC_23's user avatar
  • 9,293
2 votes

Does the fact that we are able to see CMBR implies that universe expanded faster than light?

We do not detect any CMBR from the inflationary epoch. The CMBR originated about 370000 years later, at recombination. Before that time the universe was opaque, like a star or substantially hotter. ...
Dale's user avatar
  • 102k
0 votes

Could the speed of causality be (significantly) faster than $c$?

The speed of light is routinely slowed in dielectric material and also in high gravitational fields. This is changing the dielectric constants of space increasing the capacitance per distance, which ...
Ron's user avatar
  • 5
3 votes
Accepted

How to make meaningful experiments and the methods of doing so

There are a number of things to discuss about your experimental setup and your discussion around that (and I didn't downvote). You have placed Z closer to B than C is to B. This distinction is ...
DrChinese's user avatar
  • 1,419
0 votes

Can you exit the event horizon with a rocket?

Absolutely not, mass can not exceed the speed of light, so if a rocket(made of mass) goes into the black holes event horizon it is too late, in fact at around 2r no object with mass can escape. Also, ...
Graham Harrington's user avatar
0 votes

Could reducing entanglement by unitary operations allow for FTL-communication? (and why not?)

Andrew pointed out in his answer, that the mechanism in the bottom side of the apparatus can’t possibly achieve, what it needs, while maintaining unitary, because it has to change the scalar product ...
Zaph's user avatar
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