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How do you know when two objects are so called entangled?
The Next CEO of Stack OverflowHow are atoms entangled, and can it be done remotely?What laser and BBO are needed to create entangled laser streams?How can we know that all of the results for entangled photons are not chosen when the pair is created?how are quantum entangled states mantained?Determining if two qubits in an ensemble are entangledAre particles entangled after beta decay?How can we know if a pair of particles are entangled?Would it be possible to quantum entangle two large objects?Quantum-entangled macroscopic objectsHow do we know that two quantum states are entangled?
$begingroup$
I’m not asking how would you entangle two objects. I want to know how would you know they are entangled?
quantum-mechanics quantum-entanglement
edited yesterday
Qmechanic♦
107k121981229
asked yesterday
Bill AlseptBill Alsept
2,0111721
$endgroup$
add a comment |
$begingroup$
I’m not asking how would you entangle two objects. I want to know how would you know they are entangled?
quantum-mechanics quantum-entanglement
edited yesterday
Qmechanic♦
107k121981229
asked yesterday
Bill AlseptBill Alsept
2,0111721
$endgroup$
$begingroup$
van Enk et al (2007), "Experimental procedures for entanglement verification," Physical Review A 75, 052318 (authors.library.caltech.edu/8289) reviews a few methods, with emphasis on methods that are sufficient if we assume that quantum theory is correct. This is a superset of methods that are sufficient for ruling out local hidden variables.
$endgroup$
– Chiral Anomaly
yesterday
$begingroup$
@ChiralAnomaly thanks, this Looks like a very thorough article and I will read through it.
$endgroup$
– Bill Alsept
yesterday
add a comment |
$begingroup$
I’m not asking how would you entangle two objects. I want to know how would you know they are entangled?
quantum-mechanics quantum-entanglement
edited yesterday
Qmechanic♦
107k121981229
asked yesterday
Bill AlseptBill Alsept
2,0111721
$endgroup$
I’m not asking how would you entangle two objects. I want to know how would you know they are entangled?
quantum-mechanics quantum-entanglement
quantum-mechanics quantum-entanglement
edited yesterday
Qmechanic♦
107k121981229
asked yesterday
Bill AlseptBill Alsept
2,0111721
edited yesterday
Qmechanic♦
107k121981229
asked yesterday
Bill AlseptBill Alsept
2,0111721
edited yesterday
Qmechanic♦
107k121981229
edited yesterday
Qmechanic♦
107k121981229
edited yesterday
Qmechanic♦
107k121981229
107k121981229
asked yesterday
Bill AlseptBill Alsept
2,0111721
asked yesterday
Bill AlseptBill Alsept
2,0111721
asked yesterday
Bill AlseptBill Alsept
2,0111721
2,0111721
$begingroup$
van Enk et al (2007), "Experimental procedures for entanglement verification," Physical Review A 75, 052318 (authors.library.caltech.edu/8289) reviews a few methods, with emphasis on methods that are sufficient if we assume that quantum theory is correct. This is a superset of methods that are sufficient for ruling out local hidden variables.
$endgroup$
– Chiral Anomaly
yesterday
$begingroup$
@ChiralAnomaly thanks, this Looks like a very thorough article and I will read through it.
$endgroup$
– Bill Alsept
yesterday
add a comment |
$begingroup$
van Enk et al (2007), "Experimental procedures for entanglement verification," Physical Review A 75, 052318 (authors.library.caltech.edu/8289) reviews a few methods, with emphasis on methods that are sufficient if we assume that quantum theory is correct. This is a superset of methods that are sufficient for ruling out local hidden variables.
$endgroup$
– Chiral Anomaly
yesterday
$begingroup$
@ChiralAnomaly thanks, this Looks like a very thorough article and I will read through it.
$endgroup$
– Bill Alsept
yesterday
$begingroup$
van Enk et al (2007), "Experimental procedures for entanglement verification," Physical Review A 75, 052318 (authors.library.caltech.edu/8289) reviews a few methods, with emphasis on methods that are sufficient if we assume that quantum theory is correct. This is a superset of methods that are sufficient for ruling out local hidden variables.
$endgroup$
– Chiral Anomaly
yesterday
$begingroup$
van Enk et al (2007), "Experimental procedures for entanglement verification," Physical Review A 75, 052318 (authors.library.caltech.edu/8289) reviews a few methods, with emphasis on methods that are sufficient if we assume that quantum theory is correct. This is a superset of methods that are sufficient for ruling out local hidden variables.
$endgroup$
– Chiral Anomaly
yesterday
$begingroup$
@ChiralAnomaly thanks, this Looks like a very thorough article and I will read through it.
$endgroup$
– Bill Alsept
yesterday
$begingroup$
@ChiralAnomaly thanks, this Looks like a very thorough article and I will read through it.
$endgroup$
– Bill Alsept
yesterday
add a comment |
1 Answer
1
active
oldest
votes
$begingroup$
In general you can't. That is, if you have just two particles you cannot tell whether they are entangled or not.
Entanglement reveals itself by correlations. For example if you take many pairs of particles you may find that their properties are always correlated, e.g. their spins are always opposite, and this tells you that whatever mechanism is generating the pairs of particles is entangling them. But this shows up only with repeated measurements. A single measurement cannot tell you the particles are correlated since their spins could have the values you observe just by chance.
answered yesterday
John RennieJohn Rennie
279k44557804
$endgroup$
$begingroup$
Thanks john, I assumed it involved measuring many pairs. I just wanted to confirm if correlation was the main thing we were looking for. Has anyone ever correlated two large objects which produced measurements of cos2?
$endgroup$
– Bill Alsept
yesterday
$begingroup$
@BillAlsept That's very technically complicated. Measurement affects the object (as does any other interaction). The bigger the object, the harder it is to isolate from all those influences, and the harder it is to have any confidence in your measurement. There's no reason to expect entanglement "stops" at some scale, but there's many reasons to expect that the bigger the object, the harder it gets to prove entanglement. But we do know it works on a macroscopic scale, because quantum computers are macroscopic (without relying on entanglement of every individual atom involved).
$endgroup$
– Luaan
yesterday
$begingroup$
@BillAlsept as far as I know this expt is the largest objects ever entangled
$endgroup$
– John Rennie
yesterday
$begingroup$
@JohnRennie The article is very interesting but it says the two objects are coupled to a circuit and that the circuit keeps the two objects so called entangled. Isn’t that still just a local process? This is probably more of a question for chat But the only correlations I can think of are mirrored variables from a common source. Which is not really entanglement and why I say so called entanglement. I guess what I’m saying is I could draw up an experiment where many pairs of large objects are correlated with given variables that when tested would give the results of cos2. Thanks
$endgroup$
– Bill Alsept
yesterday
add a comment |
Your Answer
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1 Answer
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1 Answer
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$begingroup$
In general you can't. That is, if you have just two particles you cannot tell whether they are entangled or not.
Entanglement reveals itself by correlations. For example if you take many pairs of particles you may find that their properties are always correlated, e.g. their spins are always opposite, and this tells you that whatever mechanism is generating the pairs of particles is entangling them. But this shows up only with repeated measurements. A single measurement cannot tell you the particles are correlated since their spins could have the values you observe just by chance.
answered yesterday
John RennieJohn Rennie
279k44557804
$endgroup$
$begingroup$
Thanks john, I assumed it involved measuring many pairs. I just wanted to confirm if correlation was the main thing we were looking for. Has anyone ever correlated two large objects which produced measurements of cos2?
$endgroup$
– Bill Alsept
yesterday
$begingroup$
@BillAlsept That's very technically complicated. Measurement affects the object (as does any other interaction). The bigger the object, the harder it is to isolate from all those influences, and the harder it is to have any confidence in your measurement. There's no reason to expect entanglement "stops" at some scale, but there's many reasons to expect that the bigger the object, the harder it gets to prove entanglement. But we do know it works on a macroscopic scale, because quantum computers are macroscopic (without relying on entanglement of every individual atom involved).
$endgroup$
– Luaan
yesterday
$begingroup$
@BillAlsept as far as I know this expt is the largest objects ever entangled
$endgroup$
– John Rennie
yesterday
$begingroup$
@JohnRennie The article is very interesting but it says the two objects are coupled to a circuit and that the circuit keeps the two objects so called entangled. Isn’t that still just a local process? This is probably more of a question for chat But the only correlations I can think of are mirrored variables from a common source. Which is not really entanglement and why I say so called entanglement. I guess what I’m saying is I could draw up an experiment where many pairs of large objects are correlated with given variables that when tested would give the results of cos2. Thanks
$endgroup$
– Bill Alsept
yesterday
add a comment |
$begingroup$
In general you can't. That is, if you have just two particles you cannot tell whether they are entangled or not.
Entanglement reveals itself by correlations. For example if you take many pairs of particles you may find that their properties are always correlated, e.g. their spins are always opposite, and this tells you that whatever mechanism is generating the pairs of particles is entangling them. But this shows up only with repeated measurements. A single measurement cannot tell you the particles are correlated since their spins could have the values you observe just by chance.
answered yesterday
John RennieJohn Rennie
279k44557804
$endgroup$
$begingroup$
Thanks john, I assumed it involved measuring many pairs. I just wanted to confirm if correlation was the main thing we were looking for. Has anyone ever correlated two large objects which produced measurements of cos2?
$endgroup$
– Bill Alsept
yesterday
$begingroup$
@BillAlsept That's very technically complicated. Measurement affects the object (as does any other interaction). The bigger the object, the harder it is to isolate from all those influences, and the harder it is to have any confidence in your measurement. There's no reason to expect entanglement "stops" at some scale, but there's many reasons to expect that the bigger the object, the harder it gets to prove entanglement. But we do know it works on a macroscopic scale, because quantum computers are macroscopic (without relying on entanglement of every individual atom involved).
$endgroup$
– Luaan
yesterday
$begingroup$
@BillAlsept as far as I know this expt is the largest objects ever entangled
$endgroup$
– John Rennie
yesterday
$begingroup$
@JohnRennie The article is very interesting but it says the two objects are coupled to a circuit and that the circuit keeps the two objects so called entangled. Isn’t that still just a local process? This is probably more of a question for chat But the only correlations I can think of are mirrored variables from a common source. Which is not really entanglement and why I say so called entanglement. I guess what I’m saying is I could draw up an experiment where many pairs of large objects are correlated with given variables that when tested would give the results of cos2. Thanks
$endgroup$
– Bill Alsept
yesterday
add a comment |
$begingroup$
In general you can't. That is, if you have just two particles you cannot tell whether they are entangled or not.
Entanglement reveals itself by correlations. For example if you take many pairs of particles you may find that their properties are always correlated, e.g. their spins are always opposite, and this tells you that whatever mechanism is generating the pairs of particles is entangling them. But this shows up only with repeated measurements. A single measurement cannot tell you the particles are correlated since their spins could have the values you observe just by chance.
answered yesterday
John RennieJohn Rennie
279k44557804
$endgroup$
In general you can't. That is, if you have just two particles you cannot tell whether they are entangled or not.
Entanglement reveals itself by correlations. For example if you take many pairs of particles you may find that their properties are always correlated, e.g. their spins are always opposite, and this tells you that whatever mechanism is generating the pairs of particles is entangling them. But this shows up only with repeated measurements. A single measurement cannot tell you the particles are correlated since their spins could have the values you observe just by chance.
answered yesterday
John RennieJohn Rennie
279k44557804
answered yesterday
John RennieJohn Rennie
279k44557804
answered yesterday
John RennieJohn Rennie
279k44557804
answered yesterday
John RennieJohn Rennie
279k44557804
279k44557804
$begingroup$
Thanks john, I assumed it involved measuring many pairs. I just wanted to confirm if correlation was the main thing we were looking for. Has anyone ever correlated two large objects which produced measurements of cos2?
$endgroup$
– Bill Alsept
yesterday
$begingroup$
@BillAlsept That's very technically complicated. Measurement affects the object (as does any other interaction). The bigger the object, the harder it is to isolate from all those influences, and the harder it is to have any confidence in your measurement. There's no reason to expect entanglement "stops" at some scale, but there's many reasons to expect that the bigger the object, the harder it gets to prove entanglement. But we do know it works on a macroscopic scale, because quantum computers are macroscopic (without relying on entanglement of every individual atom involved).
$endgroup$
– Luaan
yesterday
$begingroup$
@BillAlsept as far as I know this expt is the largest objects ever entangled
$endgroup$
– John Rennie
yesterday
$begingroup$
@JohnRennie The article is very interesting but it says the two objects are coupled to a circuit and that the circuit keeps the two objects so called entangled. Isn’t that still just a local process? This is probably more of a question for chat But the only correlations I can think of are mirrored variables from a common source. Which is not really entanglement and why I say so called entanglement. I guess what I’m saying is I could draw up an experiment where many pairs of large objects are correlated with given variables that when tested would give the results of cos2. Thanks
$endgroup$
– Bill Alsept
yesterday
add a comment |
$begingroup$
Thanks john, I assumed it involved measuring many pairs. I just wanted to confirm if correlation was the main thing we were looking for. Has anyone ever correlated two large objects which produced measurements of cos2?
$endgroup$
– Bill Alsept
yesterday
$begingroup$
@BillAlsept That's very technically complicated. Measurement affects the object (as does any other interaction). The bigger the object, the harder it is to isolate from all those influences, and the harder it is to have any confidence in your measurement. There's no reason to expect entanglement "stops" at some scale, but there's many reasons to expect that the bigger the object, the harder it gets to prove entanglement. But we do know it works on a macroscopic scale, because quantum computers are macroscopic (without relying on entanglement of every individual atom involved).
$endgroup$
– Luaan
yesterday
$begingroup$
@BillAlsept as far as I know this expt is the largest objects ever entangled
$endgroup$
– John Rennie
yesterday
$begingroup$
@JohnRennie The article is very interesting but it says the two objects are coupled to a circuit and that the circuit keeps the two objects so called entangled. Isn’t that still just a local process? This is probably more of a question for chat But the only correlations I can think of are mirrored variables from a common source. Which is not really entanglement and why I say so called entanglement. I guess what I’m saying is I could draw up an experiment where many pairs of large objects are correlated with given variables that when tested would give the results of cos2. Thanks
$endgroup$
– Bill Alsept
yesterday
$begingroup$
Thanks john, I assumed it involved measuring many pairs. I just wanted to confirm if correlation was the main thing we were looking for. Has anyone ever correlated two large objects which produced measurements of cos2?
$endgroup$
– Bill Alsept
yesterday
$begingroup$
Thanks john, I assumed it involved measuring many pairs. I just wanted to confirm if correlation was the main thing we were looking for. Has anyone ever correlated two large objects which produced measurements of cos2?
$endgroup$
– Bill Alsept
yesterday
$begingroup$
@BillAlsept That's very technically complicated. Measurement affects the object (as does any other interaction). The bigger the object, the harder it is to isolate from all those influences, and the harder it is to have any confidence in your measurement. There's no reason to expect entanglement "stops" at some scale, but there's many reasons to expect that the bigger the object, the harder it gets to prove entanglement. But we do know it works on a macroscopic scale, because quantum computers are macroscopic (without relying on entanglement of every individual atom involved).
$endgroup$
– Luaan
yesterday
$begingroup$
@BillAlsept That's very technically complicated. Measurement affects the object (as does any other interaction). The bigger the object, the harder it is to isolate from all those influences, and the harder it is to have any confidence in your measurement. There's no reason to expect entanglement "stops" at some scale, but there's many reasons to expect that the bigger the object, the harder it gets to prove entanglement. But we do know it works on a macroscopic scale, because quantum computers are macroscopic (without relying on entanglement of every individual atom involved).
$endgroup$
– Luaan
yesterday
$begingroup$
@BillAlsept as far as I know this expt is the largest objects ever entangled
$endgroup$
– John Rennie
yesterday
$begingroup$
@BillAlsept as far as I know this expt is the largest objects ever entangled
$endgroup$
– John Rennie
yesterday
$begingroup$
@JohnRennie The article is very interesting but it says the two objects are coupled to a circuit and that the circuit keeps the two objects so called entangled. Isn’t that still just a local process? This is probably more of a question for chat But the only correlations I can think of are mirrored variables from a common source. Which is not really entanglement and why I say so called entanglement. I guess what I’m saying is I could draw up an experiment where many pairs of large objects are correlated with given variables that when tested would give the results of cos2. Thanks
$endgroup$
– Bill Alsept
yesterday
$begingroup$
@JohnRennie The article is very interesting but it says the two objects are coupled to a circuit and that the circuit keeps the two objects so called entangled. Isn’t that still just a local process? This is probably more of a question for chat But the only correlations I can think of are mirrored variables from a common source. Which is not really entanglement and why I say so called entanglement. I guess what I’m saying is I could draw up an experiment where many pairs of large objects are correlated with given variables that when tested would give the results of cos2. Thanks
$endgroup$
– Bill Alsept
yesterday
add a comment |
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$begingroup$
van Enk et al (2007), "Experimental procedures for entanglement verification," Physical Review A 75, 052318 (authors.library.caltech.edu/8289) reviews a few methods, with emphasis on methods that are sufficient if we assume that quantum theory is correct. This is a superset of methods that are sufficient for ruling out local hidden variables.
$endgroup$
– Chiral Anomaly
yesterday
$begingroup$
@ChiralAnomaly thanks, this Looks like a very thorough article and I will read through it.
$endgroup$
– Bill Alsept
yesterday