Can-quantum-entanglement-be-used-for-faster-than-light-communication - by Brecht Corbeel - Quora Question review

This document contains a review of the answer by Brecht Corbeel on the question in Quora: "Can-quantum-entanglement-be-used-for-faster-than-light-communication"
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• The text in italics is copied from the article.
  
• Immediate followed by some comments
  

Contents

• 1. Answer Review

Reflection

• Reflection 1 - Question Review

1. Answer Review

The question of whether quantum entanglement can be used for faster-than-light communication is one that has intrigued physicists and laypeople alike.

The most important question is: exactly what is quantum entanglement, and how can it be demostrated.

Quantum entanglement, a phenomenon where the states of two or more particles become correlated in such a way that the state of one particle instantly influences the state of another, no matter the distance separating them, seems to defy our classical understanding of the universe.

The physical explanation is wrong. Particles, created at the result of an experiment, can not influence each other instantly. Nor at the moment when one is measured, disturbed or manual influenced
The origin of the so called quantum entangled particles lies always at moment when the particles are created. At that moment the particle are correlated, in the sense that when one particle is + the other particle is a -. This correlation is established 'later' when both particles are measured. There after, when the same reaction is repeated 100 times, this correlation becomes a physical fact. That means when only particle is measured and is a +, the outcome of the other particle can be predicted as being a -.
No special communication is involved between both particles, and no action at a distance

This phenomenon was famously described by Einstein as "spooky action at a distance," and it's one of the cornerstones of quantum mechanics.

During each experiment no "spooky action at a distance" is involved.

Let's first clarify what we mean by "faster-than-light communication." According to the theory of special relativity, nothing can travel faster than the speed of light in a vacuum.

As mentioned before no "faster-than-light communication" is involved.

This is not just a limit on the speed of particles, but a fundamental property of spacetime itself. The equations of special relativity, such as the Lorentz transformations, make it clear that as an object approaches the speed of light, its relativistic mass increases without bound, requiring an infinite amount of energy to reach or exceed the speed of light.

The concept of spacetime is not involved in any reaction (or collision) when the so called 'entangled particles' are created.

Now, quantum entanglement does involve correlations between particles that are space-like separated, meaning they are not connected by any light signal.

There exists no reaction or collision experiment, wherby particles are created which are physical connected and or are connected by light signals.

When you measure the state of one entangled particle, you instantly know something about its entangled partner.

This is not the way in which quantum mechanical experiments are performed. The problem is that when you perform any experiment for the first time it must be repeated many times. See experimental phase above.
What the experimental phase demonstrates is that both particles are correlated, not that they are entangled, implying a certain physical connection.

This has been experimentally verified through Bell tests, which rule out local hidden variables as an explanation for these correlations. However, the key point is that while the entangled states are correlated, the outcome of each individual measurement is random. You cannot control the state that you will measure.

What the experimental phase demonstrates is that both particles are correlated. If there-after only one particle is measured, the outcome of that measurement is random.

This randomness is a crucial point when considering the potential for faster-than-light communication.

There exists no process in which faster than light communication is involved.
If you receive a box with a left shoe, then you know that some one else has received the right shoe. That type of information processing, which involves in your head, does not involve faster than light communication.

If you could control the state of one of the entangled particles, then in theory, you could use entanglement to send information instantaneously.

No.

However, according to the no-communication theorem in quantum mechanics, it is not possible to send information this way.

This has nothing to do with any theorem.

The theorem states that it is impossible to transmit information solely by performing measurements on one's own particle of an entangled pair. The correlation between the entangled particles can be verified only after the parties compare their measurements, which requires a classical communication channel and thus cannot occur faster than light.

It should be understood that quantum entangled particles, which are physical connected, don't exist.
Elementary particles are not physical connected. All the protons, neutrons and electrons within an atom are not physical connected.

Quantum information theory further elaborates on this limitation. Even if you and a partner shared a large number of entangled particles, and you both performed measurements on your respective particles, the sequence of measurement outcomes would appear random to both of you. Only after you compared your results—via a classical channel limited by the speed of light—would the correlations become evident. Therefore, while entanglement is a form of quantum correlation, it does not allow for quantum signaling.

The Einstein-Podolsky-Rosen (EPR) paradox initially brought attention to the puzzling nature of quantum entanglement.

Okay.

The paradox questioned whether quantum mechanics provides a complete description of physical reality.

It is not possible to describe a complete description of the physical reality (in time)

While entanglement has been experimentally confirmed, and quantum mechanics has stood the test of time, the EPR paradox highlights the counterintuitive nature of the quantum world.

No process in the physical world can be evolve counterintuitive. Physics can never be counterintuitive. Anyway there exists no quantum world.

Yet, it's essential to note that these entangled states, as perplexing as they may be, do not violate causality or allow for faster-than-light interactions in any way that could be harnessed for communication.

Quantum entanglement has practical applications in areas like quantum cryptography and quantum computing, but these do not involve faster-than-light transmission of information.

That is correct.

In quantum cryptography, for example, the security of a communication channel is enhanced by the properties of entangled particles, but the actual exchange of messages still occurs through classical means.

3.

The most critical part of this question is: what means quantum entanglement. Other questions are: How are quantum entangled particles created.
Quantum entanglement in this context means that for example photons are created, which are physical connected. That is physical impossible.
As a result of a reaction never elementary particles can be created which are physical linked.
The creation of entangled particles is discussed in this document: Article_Review_Polarization_Correlation_of_Photons_Emitted_in_an_Atomic_Cascade.htm . However in this case they correlated not entangled.

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