I’ve started using the Greasemonkey script Webolodeon. This cool little script pops up a little screen every five minutes when you are surfing the web and asks you to justify why you are still surfing the web. Pretty cool and useful, I must say.
Approximating Zone
A new sign for outside my office:
I Want! I Want!
Wired has an article about smart interactive whiteboards. Being a theorist, whiteboards and a pen and pad of paper are two of my most useful tools. I really don’t know if one of these whiteboards would really help me, but still: they look pretty spiffy! Now if only I had a few grand stashed away
The Rest of the Story
Rumors (Uncertain Principles and Luboš Motl’s reference frame) are that the Eovtos experiment here at the University of Washington may have observed a deviation from Newton’s laws at small lengths (less than one hundred microns.) Of course this would be huge news, and their desire to take it slow is certainly understandable and, I might add, is good science.
I remember driving down the road one day and I heard the radio man Paul Harvey report that a group of physicists had discovered room temperature superconductors. I recall that I got so excited that I actually started crying. Such a discovery would presumably change the world! Alas, it turned out to not be true. Either Paul Harvey had made it up or the group’s announcement was not correct. And now you know, “the rest of the story.”
Self-Correction
Sometimes you write a paper and think it’s all ready for submission and then after you submit it to the archive you find that it is lacking for quite a few reasons. On Friday I posted the paper quant-ph/0506023 (and did the new paper dance!) But after communications from Michael Nielsen and David Poulin, I realized that I had made a mistake in one of my claims (the proof I had did not work) and that I had very much misrepresented what is new in this paper (in particular in relationship to quant-ph/0504189 and quant-ph/0412076.) Luckily the mistake in my proof was not a big deal for the paper and also luckily one can correct one’s foolishness and clarify what’s new and interesting in the paper. Here is the updated title and abstract:
Operator Quantum Error Correcting Subsystems for Self-Correcting Quantum Memories
Authors: Dave Bacon
Comments: 17 pages, 3 figures, title change, rewrite of connection to operator quantum error correction, references added
The most general method for encoding quantum information is not to encode the information into a subspace of a Hilbert space, but to encode information into a subsystem of a Hilbert space. Recently this notion has led to a more general notion of quantum error correction known as operator quantum error correction. In standard quantum error correcting codes, one requires the ability to apply a procedure which exactly reverses on the error correcting subspace any correctable error. In contrast, for operator error correcting subsystems, the correction procedure need not undo the error which has occurred, but instead one must perform correction only modulo the subsystem structure. This does not lead to codes which differ from subspace codes, but does lead to recovery routines which explicitly make use of the subsystem structure. Here we present two examples of such operator error correcting subsystems. These examples are motivated by simple spatially local Hamiltonians on square and cubic lattices. In three dimensions we provide evidence, in the form a simple mean field theory, that our Hamiltonian gives rise to a system which is self-correcting. Such a system will be a natural high-temperature quantum memory, robust to noise without external intervening quantum error correction procedures.
They Flutter Ahead of You, Your Possible Futures
I love the work I do. The fact that I get to spend large amounts of time thinking about computation and quantum theory…well I can’t believe how lucky I’ve been! And now I get to teach and yell and scream about computation and quantum theory. Yes, very lucky!
But, like most other people I know, I sometimes wonder what my life would be like if I didn’t do what I currently do. Especially at times when I don’t think I’m doing a particularly good job at the work I do, I like to muse about the different possiblities. Especially on my bus ride to work. What are my favorite daydreams? Founding a new university. Writing speculative popular science books. Touring the country delivering science lectures. None of which are really that far from what I really do. Which makes me think I am a narrow minded sheltered elitist. Which then makes me think I should do something really different, like move to a ski town and open a bookstore. Or move to a beautiful valley surrounded by mountains and become a rancher. Which makes me laugh, because these really aren’t so different for the majority of people. And then I exit the bus and get to my office and read through the list of titles in the latest Physical Review Letters, and again I can’t imagine every doing anything but my current job.
Self Promotion of Self-Correcting Paper
Everybody do the new paper dance, quant-ph/0506023
Quantum Error Correcting Subsystems and Self-Correcting Quantum Memories
Authors: D. Bacon
Comments: 16 pages
The most general method for encoding quantum information is not to encode the information into a subspace of a Hilbert space, but to encode information into a subsystem of a Hilbert space. In this paper we use this fact to define subsystems with quantum error correcting capabilities. In standard quantum error correcting codes, one requires the ability to apply a procedure which exactly reverses on the error correcting subspace any correctable error. In contrast, for quantum error correcting subsystems, the correction procedure need not undo the error which has occurred, but instead one must perform correction only modulo the subsystem structure. Here we present two examples of quantum error correcting subsystems. These examples are motivated by simple spatially local Hamiltonians on square and cubic lattices. In three dimensions we provide evidence, in the form a simple mean field theory, that our Hamiltonian gives rise to a system which is self-correcting. Such a system will be a natural high-temperature quantum memory, robust to noise without external intervening quantum error correction procedures.
A Postmortem Chewing Out
Another interesting letter in “Perfectly Reasonable Deviations From The Beaten Track: The Letters Of Richard P. Feynman” by T. Ferris (forward), R.P. Feynman (of course!), and M. Feynman (editor) is the following:
Mr. Todd Pramberg
Stockholm, Sweden
Dear Sir:
The fact that I beat a drum has nothing to do with the fact that I do theoretical physics. Theoretical physics is a human endeavor, one of the higher developments of human beings-and this perpetual desire to prove that people who do it are human by showing that they do other things that a few other humans do (like playing bongo drums) is insulting to me.
I am human enough to tell you to go to hell.
Sincerely,
Richard P. Feynman
Why do I find this letter interesting? Well when I was senior at Caltech a movie about Feynman, “Infinity” staring Matthew Broderick, was released (I’ve never seen the movie, but I’ve heard it’s a stinker.) CNN was doing a spot about the movie and Feynman’s legacy and they needed a token undergraduate to blab about Feynman so myself and the smartest physicist in my class, Sebastian Maurer, were interviewed for the spot. Sebastian attempted to get a quote on T.V. about the Feynman lectures on physics, which, if you listened to it carefully could actually be interpretted as a statement about Mao’s little red book (Feynman’s lectures on physics used to come as a series of three red books.) Here is what I said about Feynman:
Mention his name to physics students at Cal Tech[sic] today and watch their eyes light up: “One of the reasons it was easier to become a physicist was because he was so exciting and he wasn’t the typical, you know, nerd who doesn’t say anything,” said Cal Tech[sic] senior Dave Bacon
So you see, the above letter makes me realize that what I said was exactly the sort of thing which would have driven Feynman crazy. So I kind of feel like I’ve been chewed out from beyond the grave.
Saros Type 130
Today is my birthday. And if there has ever been a doubt that I am a lunatic, my birthday should set to rest that debate because I was born on a lunar eclipse. (“All work and no play make Homer something somthing.” “Go crazy?” “Don’t mind if I do!”) My mother describes being in the hospital and looking up at the moon and thinking “that’s a strange looking moon.” I guess if I was religious or superstitious, I might take this as some sort of an omen and maybe even develop a nice messianic complex. Bah! I can develop such a complex perfectly fine without the aid of superstition.
Why So Many Songs?
My apartment in Seattle has a very nice view from the skyline of Seattle, all the way up Lake Union, and then to the outskirts of Fremont (which is the self-proclaimed center of the universe, and well, if you have a statue of Lenin, a thirty foot rocket, and a troll under a bridge, well, I guess you do get to do a little braging.) On clear days, you can see the cascade in the distance as well as Mt. Rainier to the left of the skyline. And the sea planes take off and land right in the middle of the view. What is kind of nice is that every room has a nice view. The master bedroom a view of Lake Union, the main living room with nearly solid windows and deck nearly the entire view, and the guest bedroom a view of downtown.
But to the point. Here is a picture of a rainbow over Lake Union as seen from my porch which I took with my cell phone:
