I’m at SQuint 2007 which is being held on the campus of Caltech this year. Quite a turnout this year: something like 150 people attending! In fine Caltech tradition the night of my arrival I got pretty much no sleep. And I keep getting the feeling that I have a homework due somewhere on campus.
Cool work by Patricia Lee at NIST:
Abstract. We report on the experimental demonstration of radio frequency addressing of atoms in every other site of a double-well optical lattice, independent of their nearest neighbors at a distance of less than an optical wavelength. By dynamically controlling the lattice and the vector light shifts, the atoms’s spatial and spin degrees of freedom are entangled in each double well. We have also observed a coherent spin-exchange interaction between pairs of atoms in the double-well lattice, which can be used as a mechanism for a square-root-of-swap gate.
During the talks on quantum error correction, it was mentioned that in the very cool threshold paper of Aliferis, Gottesman, and Preskill (quant-ph/0504218), they call the inductive proof of the threshold theorem for fault-tolerance the “threshold dance.” This, of course, brings up the interesting question of what the dance moves are in this dance and the even more important question which is should this dance be part of my upcoming wedding?
Cool! Welcome back to Socal. I’ll wave from JPL. The heat wave is amazing.
Hee! I’m tweaking up that lattice at the moment…
The heat wave has almost dried me out 🙂
Shall I reveal the steps to the dance? Very well … although I suspect once you hear them you will not want to use it at your wedding, at least not without some alteration.
The name comes from something I wrote to John many many years ago (long before the AGP paper) expressing my frustration with our slow progress in getting a better threshold estimate:
Performed solo, in a pair, or in a large group (though more people gives a risk of bumping into each other):
Two steps forward, one step back, bang your head against the wall.
Two steps forward, one step back, bang your head against the wall.
One step sideways, twirl around, stop and stand confused.
Two steps backwards, one step front, sigh and wait six months.
[Repeat from beginning.]
John noticed a similarity to our proof of the main lemma in the AGP paper, thus the reference. And based on that proof, you might want to change the last line to
Two steps backwards, one step front! Cheer and write it up.
“Let’s just take a step back. No, I was wrong, I’m sorry, take a step forward. Now, take a step back. Step forward. Back. And then we’re cha-cha-ing!” Of course, in the movies (or “the movie”) this dance is a bit more mundane… they’re just trying to align a freakin’ laser. 🙂