How are entangled particles captured and contained?

[waylon318]

I'll admit I have a very small understanding of this phenomena in general. I read once that entangled particles are emitted as pi mesons decay. What I am unclear about is how do scientists know when to be ready to capture them and how do they contain them? Any help would be much appreciated.

 

[StevieTNZ]

Doesn't the position of the particles (among all its other properties) in question not exist until detected? Then how is it detected? Is it a fact that you have a particle before you perform the appropriate measurements which produce results you compare with that particles' entangled partner? But then before you make those appropriate measurements the particle has a definite position, which seems to me that all its other properties would be definite too.
Wouldn't when you make some measurement on the 'particle' then it will appear and collapse to one of its possible states for each of its properties?

Because what I don't understand is say entangled photons are produced they fly off in opposite directions, for example? But do they really exist then? or is it the case when a measurement is performed one can say they definitely exist?

 

[zonde]

I'll admit I have a very small understanding of this phenomena in general. I read once that entangled particles are emitted as pi mesons decay. What I am unclear about is how do scientists know when to be ready to capture them and how do they contain them? Any help would be much appreciated.

In modern photon entanglement experiments process of http://en.wikipedia.org/wiki/Parametric_down_conversion" is used to generate stream of entangled photons.
As wikipedia article says entangled pair is generated at random times and therefore you have to use equipment that registers two simultaneous clicks at different detectors.

 

[f95toli]

I'll admit I have a very small understanding of this phenomena in general. I read once that entangled particles are emitted as pi mesons decay. What I am unclear about is how do scientists know when to be ready to capture them and how do they contain them? Any help would be much appreciated.

Well, it depends on what you mean. One can for example trap a few ions in an ion trap and then entangle them. The ions will just sit there as pearls on a string.

 

[DrChinese]

I'll admit I have a very small understanding of this phenomena in general. I read once that entangled particles are emitted as pi mesons decay. What I am unclear about is how do scientists know when to be ready to capture them and how do they contain them? Any help would be much appreciated.

Welcome to PhysicsForums, waylon318!

As zonde says, most entangled pair experiments use light. You shine a laser through a special crystal, and most photons go straight through. About 1 in a million are transformed to an entangled pair which escape off angle slightly. There are special apparati to trap those and funnel them to be experimented upon.

 

[DrChinese]

Wouldn't when you make some measurement on the 'particle' then it will appear and collapse to one of its possible states for each of its properties?

Because what I don't understand is say entangled photons are produced they fly off in opposite directions, for example? But do they really exist then? or is it the case when a measurement is performed one can say they definitely exist?

Of course, the Heisenberg Uncertainty Principle always applies. Knowledge of one property implies complete uncertainty to its non-commuting partner. Also: it is possible to measure polarization without making either a position or momentum observation - and therefore there is no collapse for either of those.

 

[StevieTNZ]

Ah ok. I had always thought even if you measured one property of a quantum system, all its other properties would stop being a superposition too (of course, only one of position or momentum would stop being a superposition - due to the uncertainty principle).