[neilep (OP)]

Hello, I'm Sheepy How are ewe ?,


As a sheepy I of course collect black holes, here's my collection so far:



Genuine Bona-Fide Collection Of Black Holes Just Moments Ago
Including Phoenix A and Ton 618.


What would happen to a pair of entangled quanta/particles if one of them fell into a Black Hole ?

I don't know. I asked my Neighbour and he just ignored me despite the chloroform that I administered. Very rude...so...no luck there !!


whajafink ?

hugs and shmishes

mwah mwah xx

Neil

[Halc]

What would happen to a pair of entangled quanta/particles if one of them fell into a Black Hole ?

Nothing spectacular.  If, somehow, they were both measured and in the same way (more complicated than usual), a comparison of the two results (made only by something inside the black hole) would show the results to be correlated  The results of the BH measurement could not be known anywhere outside the black hole, so no comparison could be made outside, so it becomes just like any other non-entangled particle from that point of view.

my Neighbour and he just ignored me despite the chloroform that I administered

He's probably pretty used to you by now.

[Eternal Student]

Hi.

I agree with @Halc ,   although if you want to make it more complicated you could.
Whether all the quantum information that falls into a BH is somewhow preserved at the surface is debately but there are some pieces of information (like charge and angular momentum) that are agreed to be characteristics of a BH and an observer external to the BH should be able to determine them.

The Black Hole may be considered as a Kerr Black Hole,   it has some rotation.

The entangled property of the particles might be their spin.   Spin is an intrinsic angular momentum that the particle would have.

   Now when one particle falls in, even if it approaches the black hole radially and confers no orbital angular momentum to the BH,  it's spin will still carry in some momentum.  Angular momentum must be conserved so the black hole changes its rotation.

    Unless you can somehow isolate yourself from the gravitational effects of that BH (which would not be easy), the external observer would seem to be making some measurement of the new parameters of the BH.   The other particle should then collapse into a definite state.

     There may still be some uncertainity,   the in-falling particle could approach the BH slightly off-radially and spiral into it, effectively carrying in angular momentum this way.   GR is a non-quantum theory and we need to assign some definite positions and approach velocity vector to the in-falling particle to see how the Kerr metric may be affected.   Meanwhile, the particles were presumably modelled with a quantum theory where the position and velocity of the in-falling particle has an inherent uncertainty.
    We still don't have a competent quantum theory of gravity to the best of my knowledge.   So discussion of how you'll patch the two theories together and if the particle that remained outside the BH could only be found in one state after its partner fell in, could roll on for several pages.

Best Wishes.
   

[evan_au]

There is a rule that you can't clone a quantum state - that is equivalent to measuring it, which changes its state.

However, since a particle in the black hole can't directly affect anything outside the event horizon, there is a theoretical possibility that the quantum state remains on the event horizon, as well as falling in.
https://en.wikipedia.org/wiki/No-cloning_theorem

[neilep (OP)]

Thank you Halc,Eternal Student and Evan_au.

Phew !....I am a StEWEdent of ewe all. So, it is perfectly ok for the pair to become one ? i.e. if one particle is destroyed the other can happily enjoy a solo career ?

[evan_au]

if one (entangled) particle is destroyed the other can happily enjoy a solo career ?

Having entangled particles is not rare - it is the normal situation for most things in the universe.
- Every time a particle bumps into another (directly or indirectly), their quantum states become entwined/entangled.
- Pretty soon, every particle on Earth is entangled with every other particle on Earth.
- It takes longer, but particles on Earth can become entangled by photons from the star Sirius.

It is the exception to have a particle which is in a known quantum state - it takes a lot of work to get it into a known state, and it is easily disrupted by coming into contact with light, heat or sound in the environment, effectively entangling it once again with the unknown quantum state of "the universe".

So an entangled particle falling into a black hole is quite normal, and the rest of the surrounding universe continues unaffected - although the plasma in the accretion disk may not enjoy this liberty for very much longer...

So don't ewe stray beyond the horizon of your paddock; in that event you may become entangled with the fence (and by extension, the whole Earth).