I Curved spacetime and measurement direction

  • I
  • Thread starter Thread starter Hill
  • Start date Start date
Hill
Messages
735
Reaction score
575
TL;DR Summary
How are parallel directions for measurements of entangled particles defined in locations which are far from each other?
To be specific, let's say that two photons in EPR entangled state were sent to Alice and Bob separated by billions of light years. We know that if they measure their photon polarizations in the same direction, they certainly get the same result. My question is, what is the same direction in their case?
I assume that this is determined by the parallel transport in curved spacetime and depends on trajectories of the photons between their origin and Alice and Bob respectively. Is this assumption correct?
 
Physics news on Phys.org

Thread 'Question about Parallel Transport'

In this video I can see a person walking around lines of curvature on a sphere with an arrow strapped to his waist. His task is to keep the arrow pointed in the same direction How does he do this ? Does he use a reference point like the stars? (that only move very slowly) If that is how he keeps the arrow pointing in the same direction, is that equivalent to saying that he orients the arrow wrt the 3d space that the sphere is embedded in? So ,although one refers to intrinsic curvature...
View full post »

Thread 'Trying to calculate proper time of worldlines using rotating frames'

So, to calculate a proper time of a worldline in SR using an inertial frame is quite easy. But I struggled a bit using a "rotating frame metric" and now I'm not sure whether I'll do it right. Couls someone point me in the right direction? "What have you tried?" Well, trying to help truly absolute layppl with some variation of a "Circular Twin Paradox" not using an inertial frame of reference for whatevere reason. I thought it would be a bit of a challenge so I made a derivation or...
View full post »

Thread 'Describing the Big Bang'

I started reading a National Geographic article related to the Big Bang. It starts these statements: Gazing up at the stars at night, it’s easy to imagine that space goes on forever. But cosmologists know that the universe actually has limits. First, their best models indicate that space and time had a beginning, a subatomic point called a singularity. This point of intense heat and density rapidly ballooned outward. My first reaction was that this is a layman's approximation to...
View full post »

Similar threads

B A well defined thought experiment
2
Replies
55
Views
3K
I Uncover Traps in Spacetime Diagrams: Bob & Alice's Cases
Replies
33
Views
3K
I Request for Input: 2D Minkowski Spacetime Diagram Generator
Replies
6
Views
2K
I Parallel transport and entanglement
Replies
5
Views
1K
I Struggling with a special relativity "paradox"
Replies
47
Views
4K
A Entangled particles in curved spacetime
Replies
4
Views
2K
I Is the moment of the measurement well defined?
Replies
12
Views
2K
B Metric Line Element Use: Do's & Don'ts for Accelerated Dummies?
Replies
29
Views
2K
I Null Spacetime Intervals and Quantum Superposition
Replies
16
Views
2K
Speed of light measured in/by a parallel frame moving at c
Replies
2
Views
2K

Hot Threads

Recent Insights

Back
Top