Evolution of Photons from Bell-States to Separable States

In summary, the conversation discusses the article found at http://arxiv.org/ftp/arxiv/papers/1203/1203.4834.pdf where the authors discuss discarding clicks at H at output b" with V at output c" and claim that they are separable states regardless of whether a bell-state measurement is made on photons #2 and #3. The speaker asks for someone to explain the evolution of the photons to achieve this result, similar to what is shown for the two bell-states on page 14.
  • #1
StevieTNZ
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Hi there,

I know in this article - http://arxiv.org/ftp/arxiv/papers/1203/1203.4834.pdf - the authors discard the clicks at H at output b" with V at output c" (and vice versa), saying they are seperable states regardless of whether the decision to perform a bell-state measurement on photons #2 and #3 is made or not.

I was wondering if someone who knows their stuff could write the evolution of the photons to get that above result (including for when the photons get converted into L and R polarisation)? Similiar to what they have for their evolution of the two bell-states they detect (on page 14).

Many thanks!
 
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  • #2
@StevieTNZ did you find any more insight on this topic?
 

1. What is the concept of "Evolution of Photons from Bell-States to Separable States"?

The concept of "Evolution of Photons from Bell-States to Separable States" refers to the process by which entangled photons, initially in a Bell state, gradually lose their entanglement and become separable. This phenomenon is a result of the interaction of the photons with their environment, causing a breakdown of their quantum entanglement.

2. How do photons become entangled in the first place?

Photons become entangled through a process called spontaneous parametric down-conversion (SPDC). This occurs when a nonlinear crystal splits a single photon into two entangled photons with opposite polarizations. These photons are then correlated in their properties, even when separated by large distances.

3. What are Bell-states and separable states?

Bell-states are quantum states of two entangled particles that exhibit strong correlations, even when separated by large distances. These states were first described by physicist John Bell in 1964. On the other hand, separable states are quantum states of two particles that are not entangled and can be described independently of each other.

4. What causes the gradual loss of entanglement in photons?

The gradual loss of entanglement in photons is caused by the interaction of the photons with their environment. This can include factors such as photon absorption, scattering, and decoherence, which disrupt the delicate quantum state of the photons and lead to a breakdown of their entanglement.

5. Why is the evolution of photons from Bell-states to separable states important?

The evolution of photons from Bell-states to separable states is important for understanding the nature of quantum entanglement and its relationship with the environment. It also has practical applications in quantum communication and computing, as well as providing insights into the fundamental principles of quantum mechanics.

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