Understanding Entanglement: What it Means & How it Works

[fog37]

Hello Everyone,
I would like to understand entanglement a little more clearly. My understanding is that two or more quanta (for example photons) that are entangled become a single entity. Entangled or not, there is always a single and total wavefunction that describes the system but in the case of entanglement the total wavefunction describing the particles cannot be factored. Is that correct? What does that really mean?

Is it possible for some of system observables to become entangled while other observables remain untangled? How does that happen? Or do all the observables of each individual particle become entangled?

Thanks!

 

[DrChinese]

Hello Everyone,
My understanding is that two or more quanta (for example photons) that are entangled become a single entity. Entangled or not, there is always a single and total wavefunction that describes the system but in the case of entanglement the total wavefunction describing the particles cannot be factored. Is that correct? What does that really mean?

Is it possible for some of system observables to become entangled while other observables remain untangled? How does that happen? Or do all the observables of each individual particle become entangled?

Thanks!

You are correct that entangled systems cannot be factored. It is correct that particles may be entangled on some bases, but not entangled on all bases. Photons could be entangled as to frequency or momentum, but not as to polarization, for example.