Physics “News”: Quantum Optics Edition

I’m on vacation this week, and taking this opportunity to clear out a large backlog of news items that I flagged as interesting, but never got around to commenting on. I’ll group them thematically, just to spread things out over a few days, and this post highlights a couple of new things in the quantum optics field:

  • “Single atom entangles two photons”: pretty much what it sounds like. The Rempe group in Garching has used a single atom trapped in an optical cavity to produce an entangled pair of photons by sequential interaction between the atom and a couple of laser pulses. Like everything else in the field, this might be useful for quantum computation someday, at least if they can improve on the 1.3% efficiency…
  • “Atoms swap spins”: This is a somewhat deceptive title for a nice bit of work by my old group at NIST. They used an “optical lattice” system, which is a set of interfering lasers making a three-dimensional array of atom traps, to do quantum logic operations on atoms located in neighboring traps. They demonstrated the ability to change the state of one atom in a pair based on the state of the other atom in the pair, which is the key operation you need to be able to do to build a quantum computer. They’re not going to be factoring large numbers any time soon, but it’s a really cool demonstration.