No, there is no acceleration in photons. They're either travelling at c, or they're not existing.

What about this?

 

Lene Vestergaard Hau (born in Vejle, Denmark, on November 13, 1959) is a Danish physicist. In 1999, she led a Harvard University team who succeeded in slowing a beam of light to about 17 metres per second, and, in 2001, was able to momentarily stop a beam. She was able to achieve this by using a superfluid.

 

Also from NPR.

 

Scientists manage to stop light, hold it trapped in a cloud of chilled atoms known as a Bose Einstein condensate, and then release it in a second cloud a short distance away. We'll talk about the work and its potential applications in information processing.

 

Does anyone know if they stopped a single photon, or just the light itself but the photons kept moving. If the former, then saving a halted photon "for later" surely counts as the light having existence while unable to move at c?

the photons moved at c, they just got absorbed and remitted so often the speed AVERAGED to about 17m/s.

They also can't reflect instantaneously, as that would require information traveling faster than the speed of light (all parts of the photon would have to know that the front hit something instantly). But I'm guessing that the front of a photon can be moving in a different direction than the tail, when the photon is reflecting. I guess I should have said "average acceleration". But if photons as you say cannot accelerate, then they cannot change direction either.

 

An individual photon does not change direction, it is absorbed and re-emitted.

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What about this?

 

Lene Vestergaard Hau (born in Vejle, Denmark, on November 13, 1959) is a Danish physicist. In 1999, she led a Harvard University team who succeeded in slowing a beam of light to about 17 metres per second, and, in 2001, was able to momentarily stop a beam. She was able to achieve this by using a superfluid.

 

Also from NPR.

 

Scientists manage to stop light, hold it trapped in a cloud of chilled atoms known as a Bose Einstein condensate, and then release it in a second cloud a short distance away. We'll talk about the work and its potential applications in information processing.

 

Does anyone know if they stopped a single photon, or just the light itself but the photons kept moving. If the former, then saving a halted photon "for later" surely counts as the light having existence while unable to move at c?

 

Photons travel at c, the light appears to travel slower as IA says due to absorption and emission.

An individual photon does not change direction, it is absorbed and re-emitted.

 

Then how do you explain photon-photon scattering, or gravitational lensing? Both of these result in photons changing direction, but with nothing to absorb them. Refraction may be another example.

Correct me if I'm wrong but light curves as it is affected by gravity and therefore undergoes constant velocity acceleration (maintains c while changing direction)

 

So what is the smallest possible radius of that curvature?

But the photons path along the curved space is straight... and infitesimally close to a black hole singularity I guess it'd be infitesimally small... of course at those length scales GR breaks down, so, who knows!