Can anyone explain me this quantum entanglement experiment

In summary, this article discusses a passive entanglement quantum state tomography experiment that uses two photons to generate quantum entanglement. The article provides a detailed example of how the experiment is performed, and explains the various steps involved.
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James2018
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TL;DR Summary
Entanglement Generation in Spatially Separated Systems Using Quantum Walk
Experiment

I have encountered this experiment that generates quantum entanglement but I cannot understand its mechanism. Is the conservation of energy and momentum involved? Is interference part of this experiment? What are the phenomena that contribute together to generate entanglement in this experiment? What degree of freedom is part of the entangled state?

https://www.scirp.org/html/1-1300041_20127.htm
 
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That article was published in the Journal of Quantum Information SCience which is published by SCIRP. SCIRP was on Beall's list of predatory publishers (https://web.archive.org/web/20170103170850/https://scholarlyoa.com/publishers/) and is generally known to publish articles of questionable quality.

To be honest, I would not bother with trying to understand this article as the chances that the article is incorrect are extremely high. If you are interested in entanglement generation in quantum walks in general, it might help to have a look at the initial works on that, e.g.: https://iopscience.iop.org/article/10.1088/1367-2630/7/1/156
 
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Here is how a passive quantum entanglement experiment based on quantum state tomography would work:

In this technique, the system is left to evolve freely, without any external intervention or measurement. This is in contrast to active entanglement quantum state tomography, where measurements are performed on the system during its evolution. This is done by measuring the correlations between the particles after they have evolved for a certain period of time.

Here is an example of an experiment that could be used for passive entanglement quantum state tomography:

  1. Prepare a pair of entangled particles, such as two photons, using a source of entangled pairs
  2. Allow the pair to evolve freely for a certain period of time.
  3. Measure the correlations between the photons. This can be done by measuring the polarization of each photon using polarizing filters
  4. Repeat steps 2 and 3 for different evolution times.
  5. Use the measured correlations to reconstruct the quantum state of the system. This can be done using techniques such as maximum likelihood estimation or Bayesian inference.
  6. Verify the reconstructed state by comparing it to the expected state based on the properties of the entangled pair source.
 
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Thread closed for Moderation...
 
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This thread will remain closed. A new thread on this topic, based on a more reliable and peer-reviewed reference would be welcome.
 

FAQ: Can anyone explain me this quantum entanglement experiment

What is quantum entanglement?

Quantum entanglement is a phenomenon in quantum mechanics where two or more particles become interconnected in such a way that the state of one particle is directly related to the state of the other, no matter how far apart they are. This means that a change in one particle's state will instantaneously affect the state of the other entangled particle(s), even if they are separated by large distances.

How does the quantum entanglement experiment work?

In a typical quantum entanglement experiment, two particles, such as photons or electrons, are generated in such a way that their quantum states are entangled. These particles are then separated and sent to different locations. Measurements are performed on each particle independently. According to quantum mechanics, the results of these measurements will be correlated in a way that cannot be explained by classical physics, demonstrating the entangled nature of the particles.

What is the significance of the Bell test experiments?

Bell test experiments are designed to test the predictions of quantum mechanics against those of classical physics, specifically local realism. These experiments measure the correlations between entangled particles and compare the results to the limits set by Bell's inequalities. Violations of these inequalities provide strong evidence for the non-classical nature of quantum entanglement and support the predictions of quantum mechanics.

Can quantum entanglement be used for faster-than-light communication?

No, quantum entanglement cannot be used for faster-than-light communication. While the state of one entangled particle instantaneously affects the state of the other, this effect cannot be used to transmit information faster than the speed of light. The measurement outcomes are random, and any meaningful information transfer requires classical communication, which is limited by the speed of light.

What are the practical applications of quantum entanglement?

Quantum entanglement has several practical applications, particularly in the fields of quantum computing, quantum cryptography, and quantum teleportation. In quantum computing, entanglement is used to create qubits that can perform complex calculations more efficiently than classical bits. In quantum cryptography, entanglement ensures secure communication by detecting any eavesdropping attempts. Quantum teleportation uses entanglement to transfer quantum information between particles over long distances.

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