Entanglement Definition and 882 Threads

Sanoy19 asked this question in another thread: "Does quantum entaglement create all field that exist! as everything were bound together before big bang??" Since the question was not appropriate in the original thread, and discussion there would be off-topic, here is a separate thread for any...

1. What properties (that we are aware of/discovered) can be entangled? - spin, polarization etc 2. Can we entangled/disentangled additional properties (between a two photon pair) at any particular time? for example can we have both spin and polarization entangled at same time? - can we...

The cover story of Scientific American “Living in a Quantum World” by Vlatko Vedral really caught my attention this month. I was going to purchase “Decoding Reality: The Universe as Quantum Information” but the reviews are BRUTAL. I can’t seem to find much about this concept here in the...

I try to keep my self appraised of the current news in the field. I can not say I fully understand it, and thus the questions I am about to ask. Question #1 -------------- If you have 21 entangled atoms, and one was separated for x distance and then used for data transference...

I have seen the concept of "simultaneous causation" described in philosophy, the notion that A can cause B at a simultaneous time. This sounded suspect to me and so I asked for a reference to provide evidence that this is a real phenomenon , this is what i was provided with...

Could entanglement just be quantum coherence of the same particle( which has one of two possibles spins) and we are observing classically what is actually a quantum event? That is, what we see as two particles is really one particle acting in a quantum behavior.

I watched a recent documentry regarding the recent time travel experiments using two devices. A basic explanation: Device A sends a photon which device B recieves, device B however receives the message before Device A sends it. My question regarding this is: If device B receives the...

Those who are against superluminal communication often choose to look at a single set of 'entangled' particles as an example of communication between A(lice) and B(ob). For example, Patrick Van Esch: 'EPR, density matrices, and FTL signaling' that sees the two particles as ‘clearly defined...

What do you think of the following passage from Scientific American (June 2011): Do you believe it? That entanglement are more primary than space and time and "relativity theory must give way to a deeper theory in which space and time do not exist."? Or does entanglement work inside...

I thought quantum entanglement only occur in very isolated environment and laboratory setup. How come photosynthesis use it? Do you know of a website that illustrates how this work in very clear manner? All those paper about the photosynthesis effect are difficult as they are mainly for...

I understand how entangled systems behave [Roughly], but what causes them to do so?

First post so I'll jump straight in at the deep end (for me). Excuse me if this is a daft question but this is all new to me :) In an experiment, two electrons are entangled then separated. Someone then measures the x spin of one of them and finds it to be +. The x spin of the second...

Can macro quantum entanglement make teleportation possible?? i had a Can macro quantum entanglement make teleportation possible?? i had a kind of hypothesis...that if we entangle each and every particle of a human body with other particles which are at the destination then can't we make the...

Let’s say, state A is the opposite of state B and state B is the opposite of state A. Normally if each of the state has an opposite results of themselves to an extent that the result of a mathematical method in state A can be obtain in state B and the result of a mathematical method in state B...

Is it possible to force one of the entanglement "twins" to have a particular spin? or at the least increase the probability of a photon having a particular spin? Let me illustrate with an example: Photon A and B are an entangled pair of photons (created by striking photon C on say a BBO...

Can anyone explain to me how quantum teleportation can be achieved through quantum entanglement? I read a few days ago that scientists finally "teleported" light and I read up on it and it said something about quantum entanglement. A quick wiki search brings up something I really don't...

1. Entanglement happens, in some dimension, "outside" space and time 2. Whenever we observe a particle, we pull it back into space and time. Photon travels outside space and time, however when we try to observe it, we pull it back into space and time. 3. Also when we pull a particle back...

So i have used the search feature about the topic and found some information. But i couldn't really understand how measuring the properties of one electron and knowing the entangled particles properties can help communication through cosmic distances? As i see it, i can not say give a...

I have read many papers about polarization entangled photons, but in all of them, the photons need to be indistinguishable in time. But, what about the other degrees of freedom? They need to have the same frequency, energy, angular momentum? So, do they need to be indistinguishable in all degree...

Hello, I'm planning to do my EE of IB Diploma on quantum physics and I have a doubt concerning quantum entanglement. I know that when you have two entangled particles say, two electrons, which spin pointing in the y-axis for example, if you measure them 45º shifted in any direction you will...

I know the properties of quantum entanglement and what it does but what i don't understand is why do particles become entangled and why are they entangled... what connects two electrons that are millions of lightyears apart from each other? Do physicians really know? Is there any explenation of...

Greetings, Are there degrees of quantum entanglement? After entangled particles interact with others particles do they continue to be entangled to some degree? Becoming less entangled the more interactions that occur? So that there is complex network of entanglements? If so, could it be...

I looked into quantum entanglement thing last days and I think I got it right. At least the basics. Just one thing. Quantum entanglement concept says that when I measure the state of one particle, it affects the entangled one's state instantly. But what does this have to do with the...

In another thread https://www.physicsforums.com/showpost.php?p=3143182&postcount=34 it is stated that: So far all entanglement experiments I have read about, have a single common source, usually a pump laser passed through a BBO crystal. Can anyone provide references for actual experiments...

Entangled particles seem to have 'causal impact' on each other 'instantly' violating the allowed speed-limit of causal influence i.e. 'c'. When one of the entangled particles is measured it has an impact on the other instantly. These two events (i.e. 1. the measurement of the first particle and...

Quantum Entanglement allows spatially separated entangled particles to have impact on each other instantly (overcoming the allowed speed-limit of causal influence which is 'c'). How does Quantum Field Theory address this problem (protecting causality and chronology)?

To me, the concept of entanglement sounds like an epiphany. I’m sure I can’t find one specific moment for it but I’d like to get closer. And I’d like your help. So far, I see that Einstein had issues with Born’s matrix mechanics (1925) among other things, which heated up the Bohr Einstein...

So from what I understand of Quantum Entanglement: 1. Two particles are produced which are linked somehow so as to have the opposite spins 2. By measuring one particle, the entanglement is broken - however that you then also know the state of the other particle. This is said to be...

Hi all Can you help me? Can the quantum entanglement exist between fermions which never interacted each other? For example – if this states of fermions are described by Slater determinant Does exist some papers from scientific journals about this theme? Thank you in advance...

I read this article in the Technology Review published by MIT: http://www.technologyreview.com/blog/arxiv/26270/?p1=A3 First let me say that this is a very interesting development. But unfortunately the article has a "dumbed down" analogy for the layman, which I wish I could understand a...

Hi All, I try to understand the outcome of following setup: The idea is that in the middle, a pair of polarization entangled photons are generated (so that the polarization of right-going and left-going are opposites of each other). The setup on left side is deviced so that if the...

I’ve been thinking about the implications of Special Relativity on Entanglement. Please tell me if I’m misunderstanding anything here. So let’s say an emitter is a light-year away and sends one entangled photon toward Earth and the other away from Earth. Just when the photon reaches Earth and we...

Alright, so there's definitely a lot of Sci-Fi hype about Entanglement. I'm sort of hoping the experts on the subject can set this straight. Question: Could it actually be used to transfer information instantly from one point to another, seemingly providing FTL communication? And second, does...

Good day All, I've done a bit of reading on quantum entanglement and it seems that I'm lacking some basic knowledge about quantum physics. So here goes: (Attribute maybe substituted with state) 1. Is it possible to interact with one of this quantum entangled particles? Here interact...

All the scientific documents explaining QE that I have read always refer to the entanglement of photons, and yet some news reports state that ions such as beryllium and magnesium have been entangled (http://www.livescience.com/strangenews/090603-maco-entanglement.html) so that instead of just...

The "cause" of entanglement / coupling Hi all, two questions. I don't have a physics background (but have a decent mathematical background, and have dabbled in QM). * What is the difference between entanglement and coupling? Wikipedia says they're "almost" the same thing, except for the...

Ok, so I'm merely a high school student but I have a fair amount of physics and (non-mathematical) quantum physics down. My question has to do with entanglement and teleportation. I have a fairly low understanding of entanglement however I have heard news of teleporting being done (on a small...

Homework Statement I have in my textbook (QM by Auletta) the example of the polarization-entangled state of a pair of photons given by: |\psi\rangle_{12}=\frac{1}{\sqrt{2}}\left(|h\rangle_1\otimes|v\rangle_2+|v\rangle_1\otimes|h\rangle_2\right) The density matrix associated to such a...

Hello, I am planning to talk about the entanglement for the presentation but now I am a bit confused of between entanglement and many-particle system. Actually, I have only studied two-particle system when dealing the total angular momentum. let me assume that there are a photon and an electron...

I know this might has be posted a lot of times and I should know why entanglement doesn't carry data but this time I've thought something different. I know that if Alice and Bob share a singlet state and Alice measures her particle' spin she can't communicate anything to Bob because she can't...

Hi, We just started touching on entanglement on my course this week and I'm struggling to understand the significance of it. Take the wikipedia discussion of it. It talks about two particles being created at once, with the condition that their spins must be in opposite directions. So, separating...

Hi, I will like to ask this question about quantum entanglement and confirm the "weirdness", cos some info I get says entanglement aren't weird at all, while some says it does. Here's the question: If we prepare and get a bunch of entangled electrons bunch A and bunch B (A is entangled to...

I know this is probably an extremely simple question, but anyway... I shoot two particles towards each other. They collide, and then go their separate ways. Then I measure the position of particle A with full precision. This will allow me to determine with full certainty the position of...

Asked myself that question today, and I don't know what the answer is. Maybe I missed something somewhere in the math... Anyone know?

I've searched these forums hardcore about these questions and the wide range of answers is so confusing to me, so I hope that maybe if I provide some examples and specific questions, I may better understand. I always hear that quantum particles exhibit "intrinsic" randomness in the states they...

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I am a newbie here, just an enthusiast with an above average understanding of math and physics, but exposed to QM after I left college. I have looked through the posts and did not see a concise summary to the following. Please forgive me if I overlooked some threads. There are some...

What happens if you have 2 particles entangled, and they are both observed simultaneously? As I understand the randomness in QM, once one particle is observed, we only know certain information about the other particle, redundant information. But entangled particles being observed...

Greetings. I'm currently writing a novel that incorporates kernels of truth from current quantum physics theories and experiments. Please note that I am 100% layperson where this topic is concerned. I've tried to do my 'homework' by reading books geared toward folks like me... not smart...

Hello, I'm new to the community here at Physics Forums. I am an undergrad double majoring in mathematics/computer science. I will soon be enrolled in a double masters for both math and comp sci...and eventually would like to enroll in a physics PhD program. Well then, enough about me...here...