Argthtjtr

There is a small debate over the comment session in NASA Lands InSight on Mars video uploaded by JPL. The 1 minute and a half video is about the essential part of InSight's EDL event cropped out from the full live broadcast back on Nov 26.

The commenter posted a comment: "The actual celebration is 7 Minutes in delay." Under the reply session, a Indian user named SCIENCE SIDE claims that he's currently studying PhD in Theoretical Physics, IISc Bangalore. He replied that we actually received the signals in just 1-2 seconds with the help of MarCO CubeSats. Later on followed up with confusion from other users with his statement and asked for clarification, he then mentioned that it is relating to quantum entanglement for communications.

Whether or not that is accurate, I'd still like to ask the following: Could using entangled photons be used instead for interplanetary communications ^{(between Earth & Mars)} to shorten the real-time latency as much as possible in future?

A statement about Quantum Entanglement from Wikipedia

Entanglement is considered fundamental to quantum mechanics, even though it wasn't recognized in the beginning. Quantum entanglement has been demonstrated experimentally with photons, neutrinos, electrons, molecules as large as buckyballs, and even small diamonds. The utilization of entanglement in communication and computation is a very active area of research.

^{**Do note me if this is considered as cross-site question with any other SE site. Enclose a relatable useful reference regarding to communication in space.}

Apparently not:

I like this Quora answer. Here's part of it, the rest is worth reading as well:

No experiment conducted using entangled photons has ever demonstrated faster than light communication!

There have been many such experiments. They were not looking for faster than light communication. They were testing quantum mechanics against Einstein's local hidden variable hypothesis. They essentially have shown that quantum mechanics works as advertised.

Furthermore, there are no proposals for faster than light communication using entangled particles!

If ever there was the slightest hint that FTL communication were possible, expect a media explosion… The world would definitely notice and there would be no need to ask such questions on Quora.

As it stands, quantum mechanics is still consistent with causality and is compatible with special relativity. That means no information transfer faster than the speed of light.

Additional background:

The Forbes article/blogpost The Real Reasons Quantum Entanglement Doesn't Allow Faster-Than-Light Communication Goes into great detail on this topic. The illustration helps remind us what communications using entangled photons really means. You generate a pair somewhere else, and each of the two parties in question receives one member of the entangled pair.

Naively one might think that if the two paths were equidistant and if one person "does something" to one photon upon receiving it, this would "simultaneously" "result" in the other photon "knowing about it" and to therefore "do the other thing". Per helpful comments below, varying interpretations of the word "instantly" may be where the common misapprehension lies. This is the extent of my understanding of why some people including myself get the idea that entangled photons could allow FTL communication.

Also enjoy Veritasium's video Quantum Entanglement & Spooky Action at a Distance which does a great job of explaining some of the basics of entangled photon experiments and at the end addresses why FTL communication is not thought to be possible using them.

He replied that we actually received the signals in just 1-2 seconds with the help of MarCO CubeSats. Later on followed up with confusion from other users with his statement and asked for clarification, he then mentioned that it is relating to quantum entanglement for communications.

This is nonsense; the MarCOs received the signals in 1-2 seconds, but relaying the signals to Earth took the usual several-minute speed-of-light delay.

Quantum entanglement doesn't presently offer any way of achieving faster-than-light communication. The reasons are complex, but you can read an overview here. MarCO were not equipped with any quantum-entanglement communication devices.

As someone deeply involved in quantum information/entanglement research: You cannot, under any circumstance, use entanglement to communicate faster than lightspeed. Ever.

The "no-signalling principle" says that no information can be transferred faster than lightspeed, even using all the tricks in the quantum book. If it were to be violated, a bunch of weirdness can occur, mostly violating causality. No one has seriously proposed that we can violate the no-signalling principle; computer scientists have looked at the consequences and they're.. exciting.

You can use quantum entanglement to distribute random information between separated parties, but even that relies upon correlating your measurements either ahead of time or after the fact. This cannot be used to send particular bits of information.

I tried to understand this topic for years but never really got it. But the first answer provides a great article which made it finally click for me.

The part that is missing in a lot of explanations and the most important part is:

It’s a brilliant plan, but there’s a problem: entanglement only works
if you ask a particle, “what state are you in?” If you force an
entangled particle into a particular state, you break the
entanglement, and the measurement you make on Earth is completely
independent of the measurement at the distant star.

I'm not sure if what the article is saying is technically not correct or why other sources do not mention it, but it helped me greatly understand the problem.