Science News - "Quantum Cheshire Cat" [such a stupid name]

[alex_greene]

Scientists have managed to separate neutrons from their magnetic moment, leaving both intact - neutrons without a magnetic moment, and ghost magnetic moments physically separated by some quantum effect described as a "quantum Cheshire Cat."

BBC News

Phys.org's report on the experiment

It could be possible to separate a particle from a particular physical property and examine the particle without that property interfering with the measurements before restoring that property to the particle. Alternatively, the separated physical property could be measured independently of the particle it belonged to.

Wonder if they could be swapped around, particles and their inherent physical properties? That'd be interesting.

 

[sideranautae]

Scientists have managed to separate neutrons from their magnetic moment, leaving both intact - neutrons without a magnetic moment, and ghost magnetic moments physically separated by some quantum effect described as a "quantum Cheshire Cat."

BBC News

Phys.org's report on the experiment

It could be possible to separate a particle from a particular physical property and examine the particle without that property interfering with the measurements before restoring that property to the particle. Alternatively, the separated physical property could be measured independently of the particle it belonged to.

Wonder if they could be swapped around, particles and their inherent physical properties? That'd be interesting.

If you could get the particle far enough from its "property" you could develop FTL comm perhaps.

 

[alex_greene]

And quantum teleportation, quantum computing and quantum encryption.

This is what all that "quantum entanglement" hoorah is on about.

 

[simonh]

It could be possible to separate a particle from a particular physical property and examine the particle without that property interfering with the measurements before restoring that property to the particle. Alternatively, the separated physical property could be measured independently of the particle it belonged to.

That's not quite what's going on here. Quantum states are inherently probabilistic. As soon as you stop dealing with distributions and start measuring the particular properties of a particular particle, it's wave function is collapsed to a specific state.

Wonder if they could be swapped around, particles and their inherent physical properties? That'd be interesting.

I suspect what's going on in this experiment is that the wave functions of the quarks that make up the neutron are following different virtual paths so the wave function of the quark carrying it's magnetic moment 'may have' followed the other route than the rest of it. Now, thinking of quarks as particles, they are bound in the neutron and as a particle they can't be separated.0 Thinking of them as waves-like probability functions though, statistically they could follow different paths. However for any given particle if you actually collapsed the probability distribution of it's quarks, they'd all end up at the same place - or in this experiment, on the same path.

Simon Hibbs