Entanglement Definition and 882 Threads

hello, can we say that identical particles in atoms like electrons are entangled since their total wavefunction is antisymmetric when we swap the states? is there any condition for this entanglement?

"Four-qubit entanglement from string theory" This paper Borsten et al., "Four-qubit entanglement from string theory," http://arxiv.org/abs/1005.4915 (published in PRL) is being described http://www.sciencedaily.com/releases/2010/09/100901091938.htm in the popular press as a proposal for an...

I don't understand. Why can't we use quantum entanglement by the means of altering a state of an entangled electron so we can send an instantaneous bit of information to anywhere in the universe infinitely fast by the other electron changing its quantum state? We can can in theory transmit...

Yesterday, my 12 year old nephew asked me a physics question after we watched a documentary about Einstein and relativity on the science channel. I know just enough about physics to be dangerous, and I can usually answer his questions but this time he had me stumped, and I couldn't find...

Any measurement device used to witness the phenomenom seems like it would disrupt quantum entanglement. How do scientists manage to observe it?

Hello everyone, I recently found this forum and have a question about spooky entanglement. When I first heard of this I was very interested. How can changings in one particle effect another particle even if they were separated by hundreds, thousands or even millions of miles. One explanation...

Is it possible to move an entangled particle, without disrupting the wave function, to create a communication signal?

Consider if you will... A pair of objects in an quantum entangled state. In such a state, observing the state of one object will determine the state of the other and thus the entangled system collapses. Therefor it seems that one object carries information about its entangled twin. A...

Hello people of physics I am writing a paper for an undergraduate quantum mechanics course (my second quantum course) on the following topic The role of entanglement in quantum computing Just wondering if somebody could recommend a good paper or a good book on this topic. Any suggestions...

It is shocking paper: http://arxiv.org/abs/quant-ph/0402127

I was watching a show on TV about physics and a question popped into my head that I can't find an answer to. I remember hearing it may be possible to create tiny black holes in the LHC, so maybe you can test this, I don't know. Here is my question... What would happen if you took two entangled...

I'm sorry for the trouble, but I was hoping you guys could help me understand something about Quantum Entanglement. So if I measure the x-axis spin of an electron and get +1, then that implies the the other particle must have spin -1, correct? Also, what if I measure the spin of the...

Suppose you have a set of two particles and each of those particles is entangled with another particle in a corresponding set. You could cause wave function collapse of one of the particles to signify a 0 bit, or you could cause collapse of both particles to signify a 1 bit. The configuration on...

What would happen if one had two entangled particles and performed a position measurement on one and a momentum measurement on the other? If one kept performing these measurements, perhaps first the position measurement on a particle A, then the momentum measurement on particle B, would the...

I was just reading the new article that saying that people sent information through entangled photons, and that the photons were 10 miles apart. when entangled photons change they do so instantaneous of each other. so does this mean that even though they were ten miles apart they reacted to each...

Dear everybody... Could it be true... that Entanglement is made possible because the forces between the 2 electrons are being folded through a higher dimension, so there would be an explanation for the simultaneous reaction of the 2 electrons even if there`s a astronomical distance between...

I'd like to invite you to help me visualize the following (and point out possible flaws in the scenario). Let's assume that two particles are in an entangled state. We leave one of the particles here on Earth and put the other on a spaceship. We accelerate the spaceship to relativistic...

Hi, Source: http://arxiv.org/abs/0808.3316 I haven't studied more than the basics in QM. Therefore I don't understand the math behind quantum entanglement. Any Ideas/Suggestion/Critics about the source? Thanks.

Hello I am new to this forum, and I may make a load of mistakes. I'm sorry. I was baffled by how quantum entanglement works… rather, the concept that distance does not play a roll in the synchronized actions. Why is that?

If Quantum Entanglement is real and observable, then what is stopping us from making the following observation: provided that the big bang was real and did occur, and provided that the initial occurrence of the big bang was from a single "particle" or entity, what is stopping us from concluding...

Let's say you have a pair of electrons in the singlet spin state. I thought that Alice measuring the spin of one electron (about the "z axis") corresponded to applying the operator \hat{S}_z\otimes \hat{I} (where \hat{I} is the identity operator) to the singlet state \frac{1}{\sqrt{2}}(\uparrow...

I have two simple questions concerning the entanglement and its repercussions from the EPR paradox/bell violation. Are we assuming this is a problem from our previous knowledge of the information or is it rather a matter of quantum states being really linked, thus letting information travel...

How is it that the lack of any info transferred between 2 entangled particles means that SR and Entanglement are not in conflict? I guess what I’m really asking is, well, it sounds to me like the lack of info is really just a lack of evidence that anything is transferred instantaneously. So if...

Hi, I'm currently writing a report on quantum entanglement however getting a little confused with some of the concepts. If anyone could help with the following it would be greatly appreciated. I know that an electron has a spin; which means that is has both an electric field and a...

Quantum entanglement ? Ok, after beating my head with numerous link on net somehow Icould not grasp the idea of quantum entaglement...all i understand is two particles somehow become co-related and then when separated to any distance still maintain co-realation , the moment you see one the...

Hi All I would like to know if one can present simple definitions for entanglement and concurrence as well as experimental forms to detect them. Sincerely DaTario

I was just thinking about teleportation and wondered if spacetime could be entangled. Or if you could entangle just selected dimensions. Then that would flip the teleportation problem on it's head... Any thoughts?

What is the relationship between decoherence and entanglement? Does the decoherence destroy entanglement of system and environment?

Hi everyone, first post here :) Someone told me that information could be transmitted faster than light using quantum entanglement. I do not believe this, but I'm not really knowledgeable in this area so I started to investigate, and I haven't found an answer. I came here hoping you could help...

The linked paper describes an experiment which is intended to provide for a basis for investigating solid state spin entangled electrons. Has solid state entanglement been demonstrated before? http://physics.aps.org/pdf/10.1103/PhysRevLett.104.026801.pdf

Faster than light communication w/ Quantum Entanglement (Bell's telephone)--Possible? I got intrigued by the following description: of a faster than light communications grid over interstellar distances: http://www.seti.org.au/spacecom/quantumcom.html Normally I'd ignore such things on...

Thank you for the suggestion. I should say this is the first thread I am starting since I joined physics forums four years ago. So this thread has branched from another one -"Photon entanglement and fair sampling assumption". I noted there that, on the one hand, so far no experiments...

Dr Chinese has an admirable exposition of Bell's Inequality, here: http://www.drchinese.com/Bells_Theorem.htm From this it appears (and please correct me if I am wrong) that a pair of entangled particles each have opposite spin BUT this spin is NOT a hidden value waiting to be revealed by...

Hey guys, I'm new to to this Physics Forum. In fact, this is my first post ever. So I hope this question hasn't been asked and answered a billion times already. Suppose that you have an experiment set up where two particles that are in a vacuum with each other become entangled and then one...

I only studied basis quantum physics as a graduate, my main focus was on light technology and I didn't carry it much further from there. But the passion for understanding how the world works remains. Basically, I was wondering what would happen if one were to explain quantum phenomena not so...

I'm fairly new to my readings in Quantum mechanics, so my apologies for any mistakes in interpritation of the theory. I've read that Einstein could not come to terms with entanglement and in general most entries describe it as a really weird affect, but it really doesn't seem that way to me...

It seems to me a lot of what quantum mechanics is essentially saying is that "causality of any given event is equal and opposite to the causing event" - leading to entanglement. This is in some way analogous to the Newton's laws of "action and reaction are equal and opposite". What I...

Hi there, I am currently reading some background materials about entanglement entropy relating to black holes. I got quite confused and can I just ask (i) For example, if we have a bi-patite system, say A and B, separated by some shared boundary of the two sub-regions. Toni, an observer...

I'm working on a research paper on Quantum Entanglement and came across something I don't understand. (I assume this goes here rather than in the homework forum because it applies to a topic rather than a problem. Sorry if I'm mistaken.) From what I've read, if two electrons are entangled, one...

Hi All, (i) Could anyone tell me what entanglement entropy is and what is currently the directions of research on this topic? (ii) where can I find useful sources of this subject apart from Wikipedia? Thank you!

I am wondering why there are no discussions about correctness of fair sampling assumption in photon entanglement experiments so I would like to start one. Bell's inequalities are derived considering all emitted particles. But in real photon entanglement experiments only portion of emitted...

Dear participants of a forum. The phenomenon of quantum entanglement arises only when there is the INTERACTION between two objects of a microcosm. However there is a question: What is such INTERACTION? Whether the scattering matrix is the key moment in such interaction...

How do String Theory and Quantum Entanglement mix?

i saw a video on entanglement but one thing confused me for a two electron system the possible states were described as 6 |u,u> , |u,d>, |d,u>, |d,d> plus two more states i didnt get which two more states are there besides the above

Hi all. I'm having trouble 'getting' entanglement. We were shown the EPR paradox in a lecture once, and I didn't get it. We've also been shown quantum computing, and there was something (can't remember the details) that required an understanding of entanglement, and I didn't get it. It's a...

I'm a physics undergraduate (2nd year), and I'm just learning the basics of Quantum Mechanics. As you would expect, I've been fascinated by the elegance and...paradoxes involved. My question here is about the phenomenon of entanglement. I know the mathematics of it, but when I asked my...

Please bear with me on this one; this is a plea for understanding rather than a "the theory doesn't work" post! I'll keep the question simple... and hope the answers are equally as simple! In my naive "understanding" of entanglement, I can not refute an alternative explanation that - two...

I have some questions: Was it von Neuman that first brought up the idea that self-reference could be the reason behind the measurment problem? The idea seems to be that since a measurment device can't measure all possible interactions between a particle an itself the system (device and...

I have read an article were it is claimed that if when two photons are entangled by parametric down-conversion, you don't observe interference in the first photon (after going through a double slit) if you don't collapse the second in such a way that which-way information is destroyed. The...

Sorry people but some quantum mysteries look quite trivial to me. Wave function collapse for photons is actually subsampling of whole sample of photons. That way wave function collapse can happen instantaneously in the whole experimental setup or even backwards in time. Photon entanglement...