Physics
esiegel | June 6, 2011"As far as I see, such a theory [of the Big Bang] remains entirely outside any metaphysical or religious question. It leaves the materialist free to deny any transcendental Being. He may keep, for the bottom of space-time, the same attitude of mind he has been able to adopt for events occurring in non-singular places in space-time... Science has not to surrender in face of the Universe and when Pascal tries to infer the existence of God from the supposed infinitude of Nature, we may think that he is looking in the wrong direction." -Georges Lemaître
Recently, David Dilworth has been getting…
drorzel | June 4, 2011As I noted a while ago, I'm giving a talk at DAMOP a week from Tuesday with the title "What's So Interesting About AMO Physics?". This is intended as an introduction to the meeting as a whole, for new students or people coming in from other fields. The reason? I found a copy of the 2001 DAMOP program, which featured 270 talks and 293 posters. This year's meeting is almost twice as big: 477 talks and 548 posters. That's awfully daunting, so I'm going to try to provide an introduction/ guide to the meeting as a whole.
This, of course, requires me to know a little bit about a wide range of…
drorzel | June 3, 2011It's been a long and brutally busy week here, so I really ought to just take a day off from blogging. But there's a new paper in Science on quantum physics that's just too good to pass up, so here's a ReasearchBlogging post to close out the week.
Aw, c'mon, dude, I'm tired. What's so cool about this paper that it can't wait until next week? Well, the title kind of says it all: they measured the average trajectories of single photons passing through a double-slit apparatus. By making lots of repeated weak measurements at different positions behind the slits, they could reconstruct the average…
drorzel | June 2, 2011This is the alst week of the academic term here, so I've been crazy busy, which is my excuse for letting things slip. I did want to get back to something raised in the comments to the comments to the Born rule post. It's kind of gotten buried in a bunch of other stuff, so I'll promote it to a full post rather than a comment.
The key exchange starts with Matt Leifer at #6:
The argument is about why we should use the usual methods of statistics in a many-worlds scenario, e.g. counting relative frequencies to estimate what probabilities we should assign in the future. It is not simply about…
drorzel | June 2, 2011This morning's Links Dump included a post from Mad Mike and an entire blog on improving academic posters. For those not in the sciences, one of the traditional means of communicating research results is at a poster session where tens to hundreds of researcher each prepare a poster (usually 3'x5' or thereabouts) about their project, hang them up, then stand by them to answer questions.
Mike and the Better Posters bloggers have some very good tips on graphic design for the benefit of the scientists "gamely trying to not look depressed at the complete lack of attention their posters are…
drorzel | June 1, 2011In just under two weeks, I'll be giving an invited talk at DAMOP (that is, the annual meeting of the Division of Atomic, Molecular, and Optical Physics of the American Physical Society) that is intended to serve as an introduction to the meeting for new students or physicists from other fields. My plan is to pick 3-4 areas and give a quick summary of those subfields, highlgihting a few invited talks in that area from the full program.
My background is in cold-atom physics, so obviously I have a good idea of what's what in those areas, and I follow things like quantum information and precision…
drorzel | June 1, 2011One of the interesting things about reading David Kaiser's How the Hippies Saved Physics was that it paints a very different picture of physics in the mid-1970's than what you usually see. Kaiser describes it as a very dark time for young physicists, career-wise. He doesn't go all that deeply into the facts and figures in the book, but there's plenty of quantitative evidence for this. The claim of the book is that this created a situation in which many younger physicists were pushed to the margins, and thus began to work on marginal topics like quantum foundations, which thus began be be…
drorzel | May 31, 2011I heard David Kaiser talk about the history of quantum foundations work back in 2008 at the Perimeter Institute, and while I didn't agree with everything he said, I found it fascinating. So when I heard that he had a book coming out about this stuff, How the Hippies Saved Physics, I jumped at the chance to get a review copy.
This is, in essence, a book-length argument that I owe Frijtof "Tao of Physics" Capra, Gary "Dancing Wu Li Masters" Zukav, and even J*ck S*rf*tt* a beer.
The book expands on things that Kaiser said in that PI talk (which was really good-- you could do worse than to spend…
drorzel | May 31, 2011(This post is part of the new round of interviews of non-academic scientists, giving the responses of Adam DeConinck, who works at a company providing supercomputing resources. The goal is to provide some additional information for science students thinking about their fiuture careers, describing options beyond the assumed default Ph.D.--post-doc--academic-job track.)
1) What is your non-academic job?
I work as a systems engineer at R Systems, a company that provides high-performance computing (HPC) resources to the commercial and academic research communities. We own and operate a number of…
drorzel | May 30, 2011Last week's post about the Many-Worlds variant in "Divided by Infinity" prompted the usual vigorous discussion about the merits of the Many-Worlds Interpretation. This included the common objection that we don't know how to obtain the probability of measurement outcomes in the Many-Worlds Interpretation.
This is one of those Deep Questions that lots of people expend lots of time talking about, and I can never quite understand what the problem is. How do we obtain the probability of events in the Many-Worlds Interpretation? Using the Born rule, of course: the probability of a particular…
jdupuis | May 29, 2011I have a whole pile of science-y book reviews on two of my older blogs, here and here. Both of those blogs have now been largely superseded by or merged into this one. So I'm going to be slowly moving the relevant reviews over here. I'll mostly be doing the posts one or two per weekend and I'll occasionally be merging two or more shorter reviews into one post here.
This one, of The Trouble With Physics: The Rise of String Theory, The Fall of a Science, and What Comes Next, is from August 14, 2007.
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This one of those very rare books, books that make you truly smarter and more…
drorzel | May 27, 2011The big physics story of the week is undoubtedly the new limit on the electric dipole moment (EDM) of the electron from Ed Hinds's group at Imperial College in the UK. As this is something I wrote a long article on for Physics World, I'm pretty psyched to see this getting lots of media attention, and not just from physics outlets.
My extremely hectic end-of-term schedule and general laziness almost make me want to just point to my earlier article and have done with it. But really, it's a big story, and one I've been following for a while, so how can I pass up the chance for a ResearchBlogging…
drorzel | May 26, 2011As I've mentioned before, I'm schedule to teach a class on "A Brief History of Timekeeping" next winter term as part of the Scholars Research Seminar program. Even though I have a hundred other things to do, I continue to think about this a lot.
One of the goals of the course is to introduce students to the idea of doing research. This was primarily conceived as a humanities/ social sciences sort of thing, so most of the discussion I've seen about these has been in terms of library research. Of course, as a physicist, I very rarely need to look things up in the library. when I think about…
drorzel | May 25, 2011I learned today that the National Georgraphic Channel video I mentioned last week has actually already aired on the network. It was last week's episode of the series "Naked Science," titled Living in a Parallel Universe.
I haven't seen it, obviously, but it's running again, tomorrow (the 26th), at 4pm (Eastern (US) time). Set your DVR accordingly.
(I'm also very pleased to have learned of the air date via email from Alan Guth...)
esiegel | May 25, 2011"We are just an advanced breed of monkeys on a minor planet of a very average star. But we can understand the Universe. That makes us something very special." -Stephen Hawking
You're probably familiar with the standard picture of our Universe. You've heard it all before: that the Universe we know of -- stars, planets, atoms, etc. -- is less than 5% of the Universe's total energy. That most of the matter is dark matter, and that most of the energy in the Universe isn't matter at all, but dark energy.
But recently, we've started to discover a couple of interesting things about the atoms in the…
drorzel | May 25, 2011If I ever decided to abandon any pretense of integrity or credibility, and just shoot for making a bazillion dollars peddling quantum hokum, the particular brand of quantum philosophy I would peddle has already been laid out, in Robert Charles Wilson's Divided by Infinity. In the story, the narrator is given a copy of a "crank book" by Carl G. Soziere, titled You will Never Die, which makes an argument that is essentially a variant of the Many-Worlds Interpretation of quantum mechanics:
And the argument was seductive. Shorn of the babble about Planck radii and Prigogine complexity and the…
jhalper | May 24, 2011This week's Weizmann news stories: A "steam release valve" for inflammation, a "brake" for cell division and an "amplifier" for quantum signals.
The steam release valve mechanism also involves an amplifier - one that ramps up the inflammation signal in response to viral attack on a cell. When the signal reaches its peak, it trips a nearby protein called caspase-8, which then kills the amps, damping the signal back down. The scientists think that failures in this mechanism could be behind various inflammatory diseases.
The brake on cell division turns out to be our old friend p53. Thirty…
esiegel | May 24, 2011"If the Universe Is Teeming with Aliens... Where Is Everybody?" -Stephen Webb
As egocentric as we are, we know that not only are we but one planet of many orbiting our Sun, but that when we look up in the heavens, every point of light we see is another chance -- another opportunity -- for planets, for life, and even for intelligence.
Image credit: Ned Wright, COBE / DIRBE, and NASA.
With hundreds of billions of stars (visible here in infrared wavelengths) in our galaxy alone, we have many, many chances for life to have evolved similarly to how it did here on Earth. With hundreds of billions…
drorzel | May 24, 2011I'm teaching our upper-level lab course this term, where I do a two-part experiment on laser spectroscopy. The first part is to calibrate the free spectral range of a homemade Fabry-Perot interferometer, and the second part is to use that Fabry-Perot as a frequency marker to calibrate a diode laser scan across the rubidium hyperfine spectrum, allowing a measurement of the Rb ground-state hyperfine splitting.
That's a bunch of jargon, the details of which don't really matter. What matters is that this is a lab that involves scanning the frequency of a particular laser through some range of…
milhayser | May 21, 2011
On Built on Facts, Matt Springer writes that "there's really no such thing as a purely continuous monochromatic light wave" and "any pulse of light that lasts a finite amount of time will actually contain a range of frequencies." Pass this pulse of light through a medium such as glass, which "can have a different refractive index for each frequency," and some very weird things start to happen. On Life at the SETI Institute, Dr. Lori Fenton explains her study of "aeolian geomorphology - how wind shapes a planetary surface." As it does on Earth, weather makes wave patterns in the dunes of…