Sometimes papers on the ArXiv are crazy. From the amusing but more than a bit scary department comes this paper comparing astrophysics and prostitution.
By Popular Demand
Here is a Powerpoint copy of the talk I gave at MIT: QIP seminar talk. If you can’t view powerpoint, here is an html version.
MIT QIP Seminar
Today I will be giving a talk at the MIT QIP seminar. Here is the abstract for the talk
There are distinct physical reasons why classical computers act as naturally error free devices. Not all classical systems can act as robust classical computers. Similarly we should not expect all quantum systems to be useful for quantum computation. More interestingly we can ask the question of whether there exist (or whether we can engineer) naturally fault-tolerant quantum computers. In this talk I will discuss recent progress toward this goal and present a sequence of examples which possess many of the properties of a naturally fault-tolerant quantum computer.
I like to call this talk my “sermon on the mount” talk. In case anyone is interested in attending, the talk will be held at 16:00 hours in room 4-270.
Tempting Chronos
Well I’ve made it to MIT. But not before spending 9 extra hours in LAX due to the southern California fires! My nice easy flight back to Boston turned into a horrible 9 hours plus a redeye. Ouch. OK Chronos, I have learned my lesson. Temporal karma is worth more than gold.
Tripped
Off to MIT for ten days. From “hi”s in the 90s to “lows” in the 40s. Brrr. Notice how I have planned my trip back east to coincide with the end of day light savings time. Wahahaha!
References Not Found
Today I recieved a proof of a paper to be published with Ben Toner in PRL (quant-ph/0304076.) The APS has this neat little program which automatically checks your references. In the proofs we recieved the following error for our paper: “References [5,9] could not be located in the databases used by the system.” The references that were said to be incorrect were
J.S. Bell, Physics (Long Island City, N.Y.), 1, 195 (1964)
and
A. Einstein, P. Podolsky, and N. Rosen, Phys. Rev. 41, 777 (1935)
Funny, these entries are indeed correct and are two of the most famous papers in physics!
The King is not Dead
Today I was driving down the street in the happy suburban community of South Pasadena when I saw Kurt Cobain trying to cross the street. Of course I stopped for him and then watched him cross the street and go into the original Trader Joes.
El Color Del Crystal Con Que Se Mira
Question of the day:
If Iran was a democracy, would there be an uproar over its nuclear program?
Two Kauffman's
I’ve been reading The Present Moment in Quantum Cosmology: Challenges to the Arguments for the Elimination of Time by Lee Smolin of loop quantum gravity fame (phil-sci archive). Mostly I’m reading because I’m an addict for anything involving the notion of “the present.” In the article he discusses two questions raised by Stuart Kauffman in the context of biology and economics which Smolin has ported over to physics:
- Is it possible that there is no finite procedure by means of which the configuration space of general relativity or some other cosmological theory may be constructed?
- Even if the answer is no is it possible that the computation that would be required to carry out the construction of the configuration space is so large that it could not be complete by any physical computer that existed inside the universe?
I’m not much of a fan of the first, (Penrose-ish) question…I find it hard to imagine noncomputability being of any practical consideration because it seems to me that one always needs an “infinity” of sorts to make the noncomputable arguments. (Apologies to Michael Nielsen quant-ph 9706006.) How do I verify that the universe is doing something noncomputable with my finite means?
The second question also strikes me as a bit odd. What I like about the question is that it talks only about the construction of the “configuration space.” This is, in a way, a specific computational problem. But it also seems that it glosses over a lot because in order to use a physical theory one needs a lot more than just the configuration space. The way in which I present a configuration space has a lot to do with what I can do with this space. And even if the full physical configuration space is not tractable, this doesn’t render it useless…there are probably tractable configuration spaces. Indeed, in a beautiful universe, the tractable configuration spaces will correspond to the tractable experiments. But this is wrong in some way: we know that we can use a quantum computer to simulate a quantum experiment, but this doesn’t mean we can use a quantum computer to output the amplitude of a particular basis state: there are nontractable questions about the theory even though we can use the theory to simulate the system.
Quicksilver
I’m about halfway through Quicksilver, Neil Stephenson’s new novel. This book is going to appeal to a lot less people than Cryptonomicon, mostly because you have to be a real hard core geek to love what he’s doing in this novel, not just some half-ass computer nerd who built his last computer. That being said, and unhumbly labeling myself as a member of the former class, so far the book has me hooked.
But what I’m really writing this entry about is not to give a review of the book (see the New York Times review or Lundblad’s review.) …especially considering I haven’t finished it yet! What really struck me in reading Stephenson is how his books remind me of the best conversations I’ve had. You know one of those conversations at a party where the ideas flow like spittle from a rabid dogs mouth (hee hee!) Where you lose track of time and how cold it is standing outside on the back porch in the middle of winter but wouldn’t give up your company or the conversation for anything. In fact, when I think about all of the authors that I consider my favorites, all of them, Philip Dick, Thomas Pynchon, Jorge Luis Borges, etc. give me this same feeling.
Well in honor of Stephenson, I don’t know how to end this entry.