If writers get writer’s block, what do scientists get? Scientist’s block? Research stagnation? Creative Blockage? Perhaps the greatest parallel between doing theory and being a writer is not that they are both creative endeavors (because artistic creativity is very different from scientific creativity. two cultures? no! but different skills, most definitely!) but that practitioners of both can sufer from stagnating periods of unproductivity. In scientific academia, because there is a structured “road to tenureship,” this stagnation mostly leads (quickly!) to “alternative careers for scientists.” For writers it must similarly lead to putting their dreams of writing aside.
The past few years I’ve found myself confronting a severe case of whatever it is you call the scientist’s version of writer’s block. Why? Well part of it was a conscious decision. I wanted to make sure that the work that I did was not just good work, but was excellent work. Or at least that is the convenient myth I tell myself for my lack of productivity. Now, applying for jobs, where my lack of productivity is clearly a liabity, I often wonder if I would have done things differently. Of course this is a silly question (the past exists only as recorded in the present), and my answer is the equally unuseful “yes and no.” No, I don’t think I would have been happy with myself if I had decided to work on the easy problems which would lead to easy publications. It’s some silly integrity issue rooted deep in my psyche (I’m reminded of a line from pink floyd: “to martyr yourself to caution is not going to help at all”) Would I spend more times on some research and less on others? Probably. Would it have been smarter to try both the easy and the hard problems? Economically? yes. Spiritually? maybe not.
Radio Free Psychic
The radio station we are listening to is playing some strange bass background with lots of strange echoed voices over the top. The voices say something like “Howard is coming,” and “Howard will bring the music.”
My mom asks, “This radio is bizarre. What is this? Is this some sort of psychic radio station?”
“Are you thinking about Howard?”
“No.”
“Well then I guess it isn’t a psychic radio station.”
A New Slogan
As seen on an advertisement in the Denver airport:
Carve diem!
Waterloo
The homeless man who I saw many times walking up and down King street, the one with the sign asking for a twoey, stood in front of the picture perfect gazebo. In the heavy heavy snow, he sat, hunched over his cart, listening to the blaring song coming from the gazebo’s speakers. “He knows if you’ve been bad or good, so be good for goodness sake.”
Two Papers
Sometimes you slog through tons of papers and wonder how much the whole huge mess really matters. But then there are days like today where I found two papers which I think completely and totally rock. Maybe they don’t really matter, but they are really interesting. The first paper appear on the arXiv today, so I really didn’t have to dig for it, but the other paper I just stumbled upon and somehow missed it when it came out in 2002.
Paper 1: quant-ph/0401137
“Fast simulation of a quantum phase transition in an ion-trap realisable unitary map” by J.P. Barjaktarevic, G.J. Milburn, Ross H. McKenzie. The idea in this paper is very beatiful. Consider a system with a Hamiltonian which posses a quantum phase transition. On a quantum computer it is possible to simulate the dynamics of this Hamiltonian. Suppose that your Hamiltonian is a sum of two noncomuting terms H_1 and H_2 and that you can easily implement evolution according to each of these terms separately, i.e. you can do exp(iH_1t) and exp(iH_2t). One way to then simulate the full Hamiltonian is to “trotterize” the evolution and perform alternating infinitesimal exp(iH_1 dt) exp(iH_2dt) exp(iH_1 dt) exp(iH_2 dt)… =exp(i(H_1+H_2)t)+small error. But suppose that you don’t do this (because, for example you can’t really do good infinitesimal evolutions in the real world!) So instead you use “big” steps exp(iH_1T)exp(iH_2T)… Now you can ask, does this system have a quantum phase tranisition! So in what sense does the “big” evolution model have the same properties as the “infinitesimal” evolution mode? In this paper the authors address this issue for the ising model with a transverse field. And indeed, the authors present strong evidence that there is a quantum phase transition in the behavior of this “big” model! A summer student and I worked a bit on this problem for a different decomposition of the same Hamiltonian. As a nice summer project the summer student, Jaime Valle, wrote code to simulate this evolution. In this model we indeed did see evidence of the phase transition. And now we see that for the decomposition choosen by these authors there is direct analytic evidence of the quantum phase transition!
The second paper that I discovered which I loved was quant-ph/0206016, “The Dirac Equation in Classical Statistical Mechanics” by G.N. Ord. Now this paper, and a series of other papers by this author and coworkers, rocks! What they show is that there is a microscopic statistical mechanical model for the Dirac equation in one dimension! There is a famous prescription for obtainin the Dirac equation in one dimension which is due to Feynman. Basically this prescription works as follows. Consider a particle which moves either forwards or backwards at the speed of light. If you want to calculate the amplitude for the particle to go from spacetime point A to spacetime point B, you simply take all paths for such a particle and associate with it an amplitude which is (im)^(# corners) where m is an infinitesimal parameter, i is the square root of minus 1 and the # corners it the number of times the particle switches directions in the path. If you use this to calculate the amplitudes for all of the paths between A and B and add up all of these amplitudes, you get the kernel for the Dirac equation in one dimension!
What Ord talks about is similar to Feynman’s prescription but what Ord shows how it is possible to construct a model where the statistics of the dirac equation fully explained by a microscopic classical model. One of his version of this model has some very nice properties, like being a beautiful nonlocal hidden variable model of the Dirac equation (it is interested that even for one particle, one gets a nonlocal hidden variable model)
Childhood's End
Who are you and who am I
To say we know the reason why?
Some are born; some men die
Beneath one infinite sky.
There’ll be war, there’ll be peace.
But everything one day will cease.
All the iron turned to rust;
All the proud men turned to dust.
And so all things, time will mend.
-Pink Floyd, Childhood’s End
What Would Teller Do?
Only time will tell if and when the problems of building a quantum computer can be overcome .As information becomes the worlds most valuable commodity, the economic, political and military fate of nations will depend on the strength of ciphers. Consequently, the development of a fully operational quantum computer would imperil our personal privacy, destroy electronic commerce and demolish the concept of national security. A quantum computer would jeopardise the stability of the world. Whichever country gets there first will have the ability to monitor the communications of its citizens, read the minds of its commercial rivals and eavesdrop on the plans of its enemies. Although it is still in its infancy, quantum computing presents a potential threat to the individual, to international business and to global security. -Simon Singh
Church Time
Perhaps it is time for me to get religion.
Quantum Computing Schools
Here is a list of school rankings of graduate physics and computer science departments. These schools should all be doing quantum computing, No?
| phys | cs | phsy+cs | |
| Massachusetts Institute of Technology |
5 | 4.9 | 9.9 |
| Stanford University (CA) | 4.9 | 4.9 | 9.8 |
| University of California�Berkeley� |
4.9 | 4.9 | 9.8 |
| Princeton University (NJ) |
4.9 | 4.3 | 9.2 |
| California Institute of Technology |
5 | 4.1 | 9.1 |
| Cornell University (NY) | 4.6 | 4.5 | 9.1 |
| University of Illinois�Urbana-Champaign |
4.5 | 4.6 | 9.1 |
| Harvard University (MA) | 4.9 | 3.7 | 8.6 |
| University of Texas�Austin |
4.1 | 4.4 | 8.5 |
| University of Washington | 4 | 4.4 | 8.4 |
| Carnegie Mellon University (PA) |
3.5 | 4.9 | 8.4 |
| University of Maryland�College Park |
4.1 | 4 | 8.1 |
| University of Wisconsin�Madison |
4 | 4.1 | 8.1 |
| Columbia University (NY) | 4.3 | 3.7 | 8 |
| University of Michigan�Ann Arbor� |
4.1 | 3.9 | 8 |
| University of California�Los Angeles |
4 | 3.9 | 7.9 |
| Yale University (CT) | 4.2 | 3.6 | 7.8 |
| University of Chicago | 4.6 | 3.2 | 7.8 |
| University of California�San Diego |
4 | 3.7 | 7.7 |
| University of Pennsylvania |
3.9 | 3.8 | 7.7 |
| Brown University (RI) | 3.5 | 3.9 | 7.4 |
| Georgia Institute of Technology |
3.4 | 4 | 7.4 |
| University of California�Santa Barbara |
4.3 | 2.9 | 7.2 |
| Johns Hopkins University (MD) |
3.9 | 3.3 | 7.2 |
| Rice University (TX) | 3.4 | 3.8 | 7.2 |
| University of Colorado�Boulder |
3.9 | 3.2 | 7.1 |
| SUNY�Stony Brook | 3.8 | 3.3 | 7.1 |
| Duke University (NC) | 3.4 | 3.7 | 7.1 |
| Purdue University�West Lafayette (IN) |
3.4 | 3.7 | 7.1 |
| University of North Carolina�Chapel Hill |
3.3 | 3.8 | 7.1 |
| Rutgers State University�New Brunswick (NJ) |
3.7 | 3.3 | 7 |
| Ohio State University | 3.7 | 3.2 | 6.9 |
| University of Minnesota�Twin Cities |
3.7 | 3.2 | 6.9 |
| Penn State University�University Park |
3.6 | 3.2 | 6.8 |
| University of Virginia | 3.3 | 3.5 | 6.8 |
| Northwestern University (IL) |
3.5 | 3.1 | 6.6 |
| University of California�Irvine |
3.3 | 3.3 | 6.6 |
| University of Southern California |
3.1 | 3.5 | 6.6 |
| University of Massachusetts�Amherst |
3 | 3.6 | 6.6 |
My Dad
For those interested, I’ve pasted the article from the local newspaper, the Siskiyou Daily News about my dad.
Continue reading “My Dad”