Delayed choice quantum eraser – Yoon Vs Walborn experiment/paper

San K
Messages
905
Reaction score
1
Delayed choice quantum eraser – Yoon Vs Walborn experiment/paper

is it true that in the Walborn experiment we manipulate p, but in Yoon paper we do not?

The below link discusses the Walborn paper:
http://grad.physics.sunysb.edu/~amarch/


[PLAIN]http://grad.physics.sunysb.edu/~amarch/PHY5657.gif

s = s-photon, p = p-photon
s-photon is going down and detected by detector Ds
p-photon is going up and detected by detector Dp
The delay (path length) for p is such that s is detected at Ds well before p reaches the polarizer.
Case 1:
The polarizer/eraser is kept there and the experiment is repeated same way for say a million photons (sent one by one)
Case 2:
The polarizer/eraser is removed AFTER s is detected at Ds (and before p reaches the polarizer) and the same sequence of events is repeated same way for say a million photons (sent one by one)

Questions:
a) Will the pattern in case 1 (after correlating the entangled pairs and removing noise) be that of an interference pattern?
b) Will the pattern in case 2 1 (after correlating the entangled pairs and removing noise) be that of a non- interference pattern?


c) In case 2 (or even case 1) when s arrives
a. its position is marked? On the screen of Ds
b. However we do not know which one is the real s till we correlate with p? (i.e. remove noise)
c. Why can we not figure out s simply via timing (velocity, distance, time calculation), without having to correlate with p?

d) Case 2 is interesting because this is different from the experiment by Yoon where we do not mess with p?
Yoon paper is discussed on http://en.wikipedia.org/wiki/Delayed_choice_quantum_eraser

In the Yoon paper the path of p is not “controlled” ….hence when s strikes Ds, one could conclude that the path of p has been fixed (probabilistically) at the time struck Ds.

However the Walborn paper is different -- where we still play with P (after s has struck Ds) by keeping or removing the polarizer/eraser.

Thus

Yoon-kim = DCQE with p allowed to follow whatever path it will take
Walborn = DCQE with manipulation of p?

Yoon = one could still conclude that once s is detected, the path of p is fixed ("probabilistically")
Walborn = we are "operating" on p after s is detected, thus s that has happened in the past is showing results that correlate with p that is (being manipulated) in future?
 
Last edited by a moderator:
Physics news on Phys.org
San K said:
Delayed choice quantum eraser – Yoon Vs Walborn experiment/paper

is it true that in the Walborn experiment we manipulate p, but in Yoon paper we do not?

The below link discusses the Walborn paper:
http://grad.physics.sunysb.edu/~amarch/


[PLAIN]http://grad.physics.sunysb.edu/~amarch/PHY5657.gif

s = s-photon, p = p-photon
s-photon is going down and detected by detector Ds
p-photon is going up and detected by detector Dp
The delay (path length) for p is such that s is detected at Ds well before p reaches the polarizer.
Case 1:
The polarizer/eraser is kept there and the experiment is repeated same way for say a million photons (sent one by one)
Case 2:
The polarizer/eraser is removed AFTER s is detected at Ds (and before p reaches the polarizer) and the same sequence of events is repeated same way for say a million photons (sent one by one)

Questions:
a) Will the pattern in case 1 (after correlating the entangled pairs and removing noise) be that of an interference pattern?
b) Will the pattern in case 2 1 (after correlating the entangled pairs and removing noise) be that of a non- interference pattern?


c) In case 2 (or even case 1) when s arrives
a. its position is marked? On the screen of Ds
b. However we do not know which one is the real s till we correlate with p? (i.e. remove noise)
c. Why can we not figure out s simply via timing (velocity, distance, time calculation), without having to correlate with p?

d) Case 2 is interesting because this is different from the experiment by Yoon where we do not mess with p?
Yoon paper is discussed on http://en.wikipedia.org/wiki/Delayed_choice_quantum_eraser

In the Yoon paper the path of p is not “controlled” ….hence when s strikes Ds, one could conclude that the path of p has been fixed (probabilistically) at the time struck Ds.

However the Walborn paper is different -- where we still play with P (after s has struck Ds) by keeping or removing the polarizer/eraser.

Thus

Yoon-kim = DCQE with p allowed to follow whatever path it will take
Walborn = DCQE with manipulation of p?

Yoon = one could still conclude that once s is detected, the path of p is fixed ("probabilistically")
Walborn = we are "operating" on p after s is detected, thus s that has happened in the past is showing results that correlate with p that is (being manipulated) in future?

The answer might be that you cannot really control the randomness of the quantum/photon.
 
Last edited by a moderator:
Insights auto threads is broken atm, so I'm manually creating these for new Insight articles. Towards the end of the first lecture for the Qiskit Global Summer School 2025, Foundations of Quantum Mechanics, Olivia Lanes (Global Lead, Content and Education IBM) stated... Source: https://www.physicsforums.com/insights/quantum-entanglement-is-a-kinematic-fact-not-a-dynamical-effect/ by @RUTA
If we release an electron around a positively charged sphere, the initial state of electron is a linear combination of Hydrogen-like states. According to quantum mechanics, evolution of time would not change this initial state because the potential is time independent. However, classically we expect the electron to collide with the sphere. So, it seems that the quantum and classics predict different behaviours!
Back
Top