mox

Reading the original EPR article - and without fully grasping the algebra, mind you - I get the impression that when they're talking about "entanglement", they're describing when two particles come together, interact, and then go on their merry separate ways? Somehow that interaction (collison, bounce, forcefield interaction, whatever) makes them forever "connected" in some really weird unexplained way forevermore, no matter how far they travel. Is this correct? That sounds like "particle memory" to me lol!?

Lol I'm jusy not "getting" it!? I've looked at lots of Youtube videos, science articles etc. They ALL seem to be glossing over the details, the "logic" simply isn't there for me? That's not good enough for me! I want to understand the logical basis of the whole thing! The EPR article just seemed full of assumptions to me - eg what constitutes a "complete" and "correct" theory of physical reality, for one thing - it's philosphical twist & turns. And are experiments proving this spooky entanglement thing, it (i'm most probably wrong here, mind you) seems to be the experiments are designed to agree with the equations. I dunno, something just seems off with the whole thing ha ha...

Is there any actual DETAILED explanation out there, from the ground up, that doesn't gloss over the logic? I am learning linear algebra & stuff,  but to be honest I want it logically explained without equations. If this CAN'T be done - isn't there a big problem there?

Is there a book I can get stuck in to? Or something online that starts from "first principles" kinda stuff? Like I said, I don't need the mathematical proofs, just the chain of logic spelt out for me, no skipping steps, no presumptions we are told to take onboard with faith!

I appreciate it, thanks!

On 2/19/2012 at 6:15 PM, Observer B said:

The Trouble with Physics - Lee Smolin

One of the best modern physics books around. Not very technical, and discusses the current state of physics and the problems faced by modern science.

 

 

I enjoy Lee Smolin's books a lot. I would love to read what he has to say in hindsight today with regard to Part III of "Trouble With Physics" ("Beyond String Theory") which is nearly 15 years old now. He raises some really interesting things back then, I'd love to read where we're at right now with regards to that stuff.

Thanks! 🙂

Can anybody recommend a beginner's book on linear algebra? I read the old "EPR" paper and I want to learn that maths. Hilbert spaces, eigenfunctions, that sort of stuff.

I've tried a couple but right at the start there's some leaps of logic I just can't seem to get my heads around lol. Is there a "go-to" textbook that excels at teaching this stuff?

Thank you, this may well be where my lack of formal mathematical training is clouding my reasoning eh!

I appreciate the responses, nice forum here! 🙂

Thank you, Strange! You've given me a lot to go on, much appreciated! 🙂

It is also nice & refreshing to be able to ask such questions in a friendly and helpful forum environment (not mentioning any names out there ha ha).

5 minutes ago, Strange said:

If you were to measure the spin of the entangled partner at 90º to the angle you measure the first photon, you would find there was no correlation. If you measure the spin at some angle between 0º and 90º, you will find there is statistical correlation. The probability of this correlation can be calculated assuming the particles had "real" (defined) values for the spin or they can be calculated using the rules of quantum theory. These two calculations give different results (known as Bell's Inequality). So by measuring this, we can test whether quantum theory gives the right answer or not. (Spoiler alert: it does!)

Thanks Strange, this paragraph helps a lot, I've had trouble following along with the Bell stuff, I can follow it up with this in mind.

Can I ask, how do we actually "know" that the properties of the photon are not "actual" or "real" until we measure/detect? I understand that the very act of "measurement" is intrusive and can perturb the particle we are looking at, thus throwing up uncertainties in the results. I can understand that, say, narrowing your resolution to precisely locate a particle, you thereby lose information about how fast it is going (for velocity or momentum, you need to see the particle travelling, therefore lose the precision of location/position)... Or, I may have got this all wrong eh!?

Isn't this all about how we "interpret" quantum mechanics? Don't some interpretations actually say the particle properties do actually exist, regardless of whether we measure them or not?

If a photon, say, exists in some superposed ambiguity of states that includes all polarities etc... doesn't that mean that "realism" is out the window, and that observation (whether measuring apparatus, or our minds) basically "create" the world around us? Also, if it is "realism" we are binning, how does that solve the locality problem of two entangled particles separated at vast distances?

(Sorry for noob/lay questions, just trying to learn! 🤨 Certainly not trying to espouse any of my own ideas or anything! 🙂 I hope it's ok asking this sort of stuff here. Please let me know if I'm infringing any guidelines, thank you! 🙂)

Hi, I often wonder about "dimensions"? You could say we live in a "3D" world - but in reality, isn't that just a "volume"? Does it even make any "realistic" sense to talk about anything less than "3D", or anything more? Theoretical physicists & mathematicians talk about "zero-dimensional points", but something without any "size" cannot even be said to be a "thing", surely? Likewise for a "one-dimensional" line, or a "two-dimensional" plane - there is no "breadth", so it can't really exist outside of a mathematician's imagination? Likewise for higher dimensions, say 5, or 11, etc - isn't this nonsensical? Is discussion of "dimensions" simply playful mathematics? In reality, isn't there simply just our familiar 3-dimensional "volume"? For something to exist, it needs a volume to exist in.

(Related)... Did Einstein actually conflate "space" with "time"? Did he actually claim that time was just another spatial dimension? Or did he simply say space and time were connected at a fundamental level, albeit different entities? Wouldn't it be better to say there is a "volume" moving through "time"?

Hi, new here! 😀

I'm not "getting" the idea of entanglement? I read an analogy online - you buy a pair of shoes, take the box home & open it, only to find just one shoe in the box. By implication, the other shoe is still back at the store, and will be the other "foot" to what you have at home. Although just an analogy, I don't see how that's any different to two entangled photons, which by their very "entanglement" have oppositive polarities. No "locality" or "realism" is being violated, surely? The photons could be at opposite ends of the universe, but when we check one's polarity, we KNOW the other one will be the opposite! Where is the problem? Where's the "quantum weirdness"?