4 ms·

IANAP and the article is lacking on details where I most want them, but how does this show that the diamonds themselves are entangled, and not just the split li

IANAP and the article is lacking on details where I most want them, but how does this show that the diamonds themselves are entangled, and not just the split light beam (à la the double-slit experiment)?

jessriedel 15y ago
I believe the idea is that the photons are entangled with a certain vibrational mode in the diamonds. When you do an interference experiment with the photons, it demonstrates that the photons are in a coherent superposition. If the vibrational mode in the diamonds had decohered, the photons would have automatically been decohered as well (since they were entangled with the diamonds). It's hard to tell for sure without being able to read the journal article, though. Also, it's important to note that the center-of-mass position of the diamonds has not been put in a superposition, which is what people usually mean when they say "macroscopic superposition". This experiment only shows that a certain vibrational mode in the diamond is superposed. (For all I know, that vibrational mode might just involve a few atoms.) Unfortunately, this type of link-bait is quite common in the quantum information community.
jessriedel 15y ago
OK, I've taken a look at the actual article and it was basically what I suspected. First, they entangle the two diamond modes by beam-splitting a photon and directing the two possible photon paths towards the diamonds. (The photon scattered off the diamonds is recombined with a beam splitter and then detected, to ensure that the scattering occurred.) Then, they hit each diamond with a lazer pulse which, if the diamond's mode was excited, produced a second photon. They were able to coherently interfere the second photon, which was in a super position of originating from the first diamond and from the second diamond.

4 ms·

IANAP and the article is lacking on details where I most want them, but how does this show that the diamonds themselves are entangled, and not just the split li

by colanderman 15y ago

jessriedel 15y ago
I believe the idea is that the photons are entangled with a certain vibrational mode in the diamonds. When you do an interference experiment with the photons, it demonstrates that the photons are in a coherent superposition. If the vibrational mode in the diamonds had decohered, the photons would have automatically been decohered as well (since they were entangled with the diamonds). It's hard to tell for sure without being able to read the journal article, though. Also, it's important to note that the center-of-mass position of the diamonds has not been put in a superposition, which is what people usually mean when they say "macroscopic superposition". This experiment only shows that a certain vibrational mode in the diamond is superposed. (For all I know, that vibrational mode might just involve a few atoms.) Unfortunately, this type of link-bait is quite common in the quantum information community.
jessriedel 15y ago
OK, I've taken a look at the actual article and it was basically what I suspected. First, they entangle the two diamond modes by beam-splitting a photon and directing the two possible photon paths towards the diamonds. (The photon scattered off the diamonds is recombined with a beam splitter and then detected, to ensure that the scattering occurred.) Then, they hit each diamond with a lazer pulse which, if the diamond's mode was excited, produced a second photon. They were able to coherently interfere the second photon, which was in a super position of originating from the first diamond and from the second diamond.