Physics
drorzel | August 29, 2008No, not me. Not literally, anyway-- I'm quite happy with my current family.
Sigma Pi Sigma, the APS, and the AAPT are running a program called "Adopt-a-Physicist to help high school students learn more about what careers in physics are like:
Physicists and students interact through discussion forums for a three-week period. Before the three week period begins, the physicists and classes (via the teachers) each create a brief introduction page. After registration closes, teachers choose some physicists for their classes to interact with, preferably from different career categories.
The…
rallain | August 28, 2008I recently saw a comment on a blog somewhere about putting satellites into space (I think it was from a post about a rocket that blew up). The poster suggested using a giant catapult to put things in space instead of rockets. Maybe he or she was kidding, or maybe not. But I have heard this idea before. Would it work?
First, how do things get in orbit? Orbit is a motion in which the gravitational force on an object makes it move in a circle around another object. In order to be in a circular orbit, it takes a certain amount of energy.
Let me just start with some calculations. How fast…
drorzel | August 28, 2008As I said in the introduction to the previous post, this was the first paper on which I was the lead author, and it may be my favorite paper of my career to date. I had a terrific time with it, and it led to enough good stories that I'm going to split the making-of part into two posts.
The experiment itself was based on an earlier paper by Phil Gould at UConn. Phil was a post-doc at NIST back in the day, and used to visit our group fairly regularly. On one of these visits, he stopped by the xenon lab, and gave me a pre-print of their time-resolved collision paper, saying "You guys really…
drorzel | August 28, 2008This paper is the third of the articles I wrote when I was a grad student, and the first one where I was the lead author. It's also probably my favorite of the lot, not just because of the role it played in my career, but because it packs a lot of science into four pages.
The whole thing is summarized in this figure from the old NIST web page, which is a simplified version of Figure 2 from the paper itself:
This shows the collision rate as a function of time after we hit a cold sample of atoms with a 40ns pulse of laser light tuned near the atomic resonance frequency. As discussed in the…
rallain | August 27, 2008Maybe you can tell I am watching the MythBuster's Moon Special. In the show, the MythBusters go in a plane to reproduce the gravitational forces on the moon. I previously went over this, so here is the link:
[Tutorial on how gravity and weightlessness (zero-g) work](http://scienceblogs.com/dotphysics/2008/09/gravity-weightlessness-and-a…)
rallain | August 27, 2008Clearly the MythBusters did this before I did (it's just airing tonight though). I just wanted to say that I posted some videos of the Apollo "jump salute" video analysis and also sped it up to "Earth-like" accelerations. I then made a video of my daughter doing the same thing on Earth and slowed it down. Yes, the MythBusters did it better, but I just wanted to say "me too". My analysis is here:
[Undoing Fake Moon Landing Videos](http://www.dotphys.net/files/moon-time.html)
P.S. I also slowed down a video of Kobe Bryant Jumping so he has an acceleration of that on the moon.
rallain | August 26, 2008Heat. You have heard it before. You have used it. I have even used it. Do we need this word? No. Is this a useful word? No.
Let me start with the definition as usually stated in a physics type text: (this is from [dictionary.com](http://dictionary.reference.com/browse/heat))
*heat:* a nonmechanical energy transfer with reference to a temperature difference between a system and its surroundings or between two parts of the same system.
This definition is fine. It is not wrong, but is it needed? Not really. Couldn't we just say energy transfer? Actually, I like to use this in the…
rallain | August 26, 2008I know the olympics are basically over. Really, I should have posted this earlier. Anyway, the gymnastics feat that always impresses me is the Iron Cross (I think that is what it is called). I know you have seen this, but here is a picture from wikipedia:
(http://en.wikipedia.org/wiki/Rings_(gymnastics))
Why is this so impressive? Why is this so difficult? Let me start with something completely different that is exactly the same (in some ways).
Here is a heavy box hung from a rope that has…
drorzel | August 26, 2008NIST's Dave Wineland has been awarded the National Medal of Science. Wineland is one of the most impressive figures in modern AMO physics, with a long list of accomplishments. As the NIST release explains:
Wineland is internationally recognized for developing the technique of using lasers to cool ions (electrically charged atoms or molecules) to near absolute zero, the coldest possible temperature. Wineland achieved the first demonstration of laser cooling in 1978 and has built on that breakthrough with 30 years of experiments that represent the first or best in the world - often both - in…
rallain | August 25, 2008Dear RapidWeaver,
What did I do to you? I like you, I really do - but this is why we broke up. It's not you, it's me. No wait, it's you. I am looking back through my old dotphys posts and most of my introductions are GONE. I was starting to think I was crazy when I wrote these. Take for instance [My analysis of Kobe Bryant's Jump](http://dotphys.net/files/kobe.html). Isn't it odd how this starts? That is because it is MISSING the first paragraph. The only reason I know I am not insane is because of Apple's Time Machine. I went back and looked and the older file has an intro.…
drorzel | August 22, 2008Every time I mention the idea of teaching physics to a wider audience than just physics majors, somebody brings up Richard Muller's course, "Physics for Future Presidents," at Berkeley. So, I was pleased to find out that he has turned the course into a book, also titled Physics for Future Presidents, with the subtitle "The Science Behind the Headlines." I was going to try to cadge a free copy from his publisher, but our default local Borders is closing, and they were offering deep discounts on all their stock, so I just bought a copy.
The book is framed as a sort of memo to somebody who will…
drorzel | August 21, 2008The experiment described in the previous post was published in early 1998, but the work was done in 1997. This was the year when things really turned around for me in grad school-- the optical control paper was done in the summer 0f '94, and '95 and '96 were just a carnival of pain. Everything in the lab broke, was repaired, and then broke again.
The lead guy on the lattice collision experiment was a post-doc named John Lawall, who really took charge. He completely re-vamped the lock system for the laser, and spent a huge amount of time re-doing the laser alignment for the trap and the…
drorzel | August 21, 2008I announced my intention to do some research blogging a little while ago, and managed one pair of posts before the arrival of SteelyKid kind of distracted me. I'm still planning to complete the Metastable Xenon Project blog, though (despite the utter lack of response to the first two), and the second real paper I was an author on is "Suppression and Enhancement of Collisions in Optical Lattices," a PRL from 1998, with a preprint version available here.
So, this is another paper about collisions, obviously, but what's an optical lattice? An optical lattice is an arrangement of laser beams--…
drorzel | August 20, 2008The Mad Biologist points to and agrees with a post by Jonathan Eisen with the dramatic title "Why I Am Ashamed to Have a Paper in Science. Eisen's gripe is mostly about Science not being Open Access, but he throws in a complaint about length restrictions, which is what the Mad Biologist latches on to and amplifies. Eisen writes:
Science with its page length obsession forced Irene to turn her enormous body of work on this genome into a single page paper with most of the detail cut out. I do not think a one page paper does justice to the interesting biology or to her work. A four page paper…
drorzel | August 20, 2008Via Swans On Tea, a ranty blog post titled Sucky Schools - How To Repair Our Education System, which takes its structure and much of its tone from Paul Lockhart's "Mathematician's Lament" (which, unfortunately, is a PDF file). I'm fond of ranty posts about education reform, but both of these kind of lose me. Lockhart, in particular, strikes me as being an excellent example of the dangers of being too attached to a subject.
He writes with great passion and at great length about the fun and creativity involved in math, which is all very nice. Unfortunately, it also leads to paragraphs like this…
drorzel | August 18, 2008A while back, after handing in my manuscript and before SteelyKid, I asked readers to suggest blog topics. I got to a few of them already, but there's one more that I've been meaning to comment on, from tcmJOE:
I'm a physics undergrad about to begin my final year, and while I'm still thinking of physics grad school, I'm starting to feel less and less inclined to go into academia. Would you talk some more about career options for physics students outside of academia/pure research?
In many ways, I'm a lousy person to ask about this-- I went directly from college into physics grad school, with…
pontiff | August 11, 2008Last week, before I headed to my current location in the land of Coca Cola and the Cartoon Network (the hotel is so nice here that when my friend stopped outside so that I could drop my bags off, the concierge asked him if he wanted would like some water while he waited), I attended a very inspirational talk on open access by Jonathan Eisen. The video is now available online (lecture 2.) Well worth watching as it was a good talk laying out the case for open access to research journals (which Eisen makes sure to delineate from open science. Say the word open science, I guess, and some…
pontiff | August 5, 2008Physics and Physicists points to an article: "The Einstein formula: E_0=mc^2 'Isn't the Lord laughing?'" by L.B. Okun on confusion about Einstein's famous mass and energy formula.
Abstract:The article traces the way Einstein formulated the relation between energy and mass in his work from 1905 to 1955. Einstein emphasized quite often that the mass $m$ of a body is equivalent to its rest energy $E_0$. At the same time he frequently resorted to the less clear-cut statement of equivalence of energy and mass. As a result, Einstein's formula $E_0=mc^2$ still remains much less known than its…
pontiff | August 5, 2008Summary of what's new and happening on the arXivs according to voters on SciRate.
0807.4935 (15 scites) "Quantum Communication With Zero-Capacity Channels" by Graeme Smith and Jon Yard.
I blogged about this article here.
0807.4753 (9 scites) "Counterexamples to the maximal p-norm multiplicativity conjecture for all p > 1" by Patrick Hayden and Andreas Winter
One of the largest one questions in quantum information theory is the additivity of the Holevo capacity of quantum channels. The Holevo capacity of a quantum channel is the rate at which you can send classical information down this…
drorzel | August 5, 2008One of the things I'd like to accomplish with the current series of posts is to give a little insight into what it's like to do science. This should probably seem familiar to those readers who are experimental scientists, but might be new to those who aren't. I think that this is one of the most useful things that science blogs can do-- to help make clear that science is a human activity like anything else, with its ups and downs, good days and bad.
To that end, I'm going to follow the detailed technical explanation of each of these papers with a post relating whatever anecdotes I can think…