Physics
drorzel | July 15, 2013One thing I left out of the making-of story about the squeezed state BEC paper last week happened a while after publication-- a few months to a year later. I don't quite recall when it was-- I vaguely think I was still at Yale, but I could be misremembering. It's kind of amusing, in an exceedingly geeky way, so I'll share it, though it's also a story of an embarrassing mis-step on my part.
So, the physical situation we were studying is described by the "Bose-Hubbard Hamiltonian": Bose because it's dealing with bosons (there's also a Fermi-Hubbard version, I believe); Hubbard after [mumble]…
esiegel | July 12, 2013"By denying scientific principles, one can maintain any paradox." -Galileo Galilei
Day and night. It seems like the simplest, most natural thing about our world, that the Sun illuminates one half of the Earth at a time.
Image credit: Public Domain Image from Desktop Wallpaper HD.
While the Earth spins on its axis, orbiting the Sun, roughly half of our lives are spent bathed in the glorious daylight provided by our parent star. The other half is spent in the dark of night, our world illuminated only by the distant stars and galaxies visible from a great distance, along with a few nearby…
drorzel | July 12, 2013I spend a lot of time promoting Rhett Allain's Dot Physics blog, enough that some people probably wonder if I get a cut of his royalties (I don't). I'm going to take issue with his latest, though, because he's decided to revive his quixotic campaign against photons, or at least teaching about photons early in the physics curriculum. We went through this back in 2008 and 2009 (though Rhett's old posts are linkrotted away, so you only get my side of the story...). I'm no more convinced this time around, even though he drags in Willis Lamb and David Norwood for support.
There are basically two…
drorzel | July 11, 2013Yesterday's write-up of my Science paper ended with a vague promise to deal some inside information about the experiment. So, here are some anecdotes that you would need to have been at Yale in 1999-2000 to pick up. We'll stick with the Q&A format for this, because why not?
Why don't we start with some background? How did you get involved in this project, anyway? I finished my Ph.D. work at NIST in early 1999, graduating at the end of May. I needed something to do after that, so I started looking for a post-doc by the don't-try-this-at-home method of emailing a half-dozen people I knew…
esiegel | July 10, 2013"It followed from the special theory of relativity that mass and energy are both but different manifestations of the same thing — a somewhat unfamiliar conception for the average mind." -Albert Einstein
You've heard and seen it plenty of times: Einstein's most famous equation, E = mc2. I've taken you inside this equation before, which lays out how much energy is stored in matter-at-rest, and tells you how much energy you need to create matter in the first place.
Image credit: Niels Madsen, ALPHA / Swansea / CERN.
That's right, you can create matter directly from energy; we do it all the…
drorzel | July 10, 2013In Monday's post on squeezed states, I mentioned that I really liked the question because I had done work on the subject. This is, in fact, my claim to scientific fame (well, before the talking-to-the-dog thing, anyway)-- I'm the first author on a Science paper with more than 500 citations having to do with squeezed states. And since I've never written it up on the blog before, I'll leap on this opportunity to do some shameless self-promotion...
Well, aren't we Mr. Ego today? What's this paper that you're so impressed with about? I've never been all that good with titles, but I like to think…
drorzel | July 9, 2013There was a flurry of discussion recently on campus about "critical thinking," and how we sell that idea to prospective and current students. This was prompted by a recent report arguing for the importance of the humanities and social sciences (which I found really frustrating in ways that are neither surprising nor important for this post). This eventually led to a meeting on Monday this week to discuss this sort of thing, in the course of which one of our Deans mentioned an abandoned project to collect statements about the modes of thinking associated with particular disciplines, which I…
drorzel | July 8, 2013In the Physics Blogging Request Thread the other day, I got a comment so good I could've planted it myself, from Rachel who asks:
It’s a term I see used a lot but don’t really know what it means – what is a “squeezed state”? What does “squeezing” mean? (in a QM context of course…)
I love this, not only because it gives me an excuse to talk about cool physics, but because it will let me engage in blatant self-promotion-- I have a Science paper on squeezed states, which I've never actually written up for the blog. So this post will be a great way to set up a future post, ResearchBlogging that…
esiegel | July 5, 2013"I see a lot of new faces. But, you know the old saying, 'out with the old, in with the nucleus.'" -The Simpsons
Looking around the Universe today, there's no doubt that there's plenty of hydrogen and helium around; after all, it's the nuclear fusion of hydrogen into helium that powers the vast majority of stars illuminating the entire cosmos!
Image credit: ESA/Hubble, NASA and H. Ebeling.
But here on Earth, hydrogen and helium are only a small part of the world we inhabit. By mass, hydrogen and helium combined make up far less than 1% of the Earth, and even if we restrict ourselves to the…
esiegel | July 3, 2013"To disagree leads to study, to study leads to understanding, to understand is to appreciate, to appreciate is to love. So maybe I'll end up loving your theory." -John Wheeler
Out there in the Universe, there's a lot to marvel at. Over billions of years, gravity has attracted different portions of the expanding Universe together into large superclusters and filaments, each made up of clusters, groups, and individual galaxies separated by great cosmic voids.
Image credit: Sloan Digital Sky Survey, 2dF Galaxy Redshift Survey, and Millenium Simulation.
From the observations of this structure…
catdynamics | July 3, 2013I am at a meeting at an undisclosed location, and concurrently the weak lensing folk are having a workshop on future surveys, so I am slumming at their sessions in my copious spare time.
This morning Tony Tyson is leading a discussion on the technical aspects of the surveys, with LSST as the working example.
That is all well and good, and it is actually extremely interesting to hear people talk about the nitty gritty - I think it is good for theorists to hear about what it is really like down in the trenches, as it were.
But, the really interesting aspect is the discussion diverged into…
drorzel | July 2, 2013Having said that I want to focus more on positive stuff, and talking up cool things in science, I'm going to make an effort to do more write-ups of research papers. I've got a few ideas along those lines, and of course I get regular emails from journals and press offices bringing other papers to my attention. But I don't want to neglect my audience, here...
So, I'll throw this open as a place to request discussions of particular topics or papers. If there's some topic in physics that you'd like me to write up an explanation of, or a paper or preprint that you'd like me to do the detailed Q…
carlyo | June 28, 2013Stephen Hawking: Theoretical Physicist and Bestselling Author
Stephen Hawking is often regarded as one of the most brilliant theoretical physicists since Einstein. He is best known for his compelling insights into such areas as Black Holes, relativity and quantum mechanics.
Since bursting onto the international scene in 1988 with his bestselling book, “A Brief History of Time", Stephen Hawking has become synonymous with helping us understand fundamental mysteries of physics and our existence, such as: Where did the universe come from? How and why did it begin? Will it come to an end, and if…
esiegel | June 26, 2013“...the magnificence of the Universe as revealed by modern science might be able to draw forth reserves of reverence and awe hardly tapped by the conventional faiths.” -Carl Sagan
As many of you know, I'm fortunate enough to live in a city that values science and scientific knowledge so highly that the our local news station, KGW, routinely brings on scientists to talk about the lastest developments in our endeavors to understand the Universe around us. Just last week, I was invited to share five wonderful minutes of airtime with the viewers of not just Portland, OR, but (thanks to the web)…
drorzel | June 26, 2013 I'm always a little ambivalent about writing up papers that have also been written up in Physics: on the one hand, they make a free PDF of the paper available, which allows me to reproduce figures from the paper in my post, since I'm not breaking a paywall to do it. Which makes it much more attractive to write these up. On the other hand, though, they do a pretty good job writing accessible descriptions, so there's not that much for me to add.
In the case of this paper, I'll write it up anyway (albeit somewhat more briefly than usual, because they already did a nice job), just because the…
drorzel | June 25, 2013Kate had to leave at 7am this morning to go to a "retreat" for her office, so I took the kids to Dunkin' Donuts for breakfast. That got us all out the door at the same time, avoiding the freakout from The Pip if he saw Mommy leave without him. Kate will be late getting home tonight, as well, so I've got dinner with the kids as well, and SteelyKid has already declared that she wants to go to the Irish pub downtown for sweet potato fries and fish & chips.
I mention this not because I want to fill the blog with trivial details of my personal life-- that's what Twitter is for-- but because it…
drorzel | June 22, 2013One of the great things about "Fermi Problems" is that there are multiple ways of attacking them. So, for example, when considering the death ray plot yesterday, I used medical devices as an example system to assess the plausibility of the plot, while Physics Buzz talked total energy. But those aren't the only ways to approach this, and turning it over last night, I thought of another approach.
As I mentioned in yesterday's post, I normally think of light in terms of photon flux or energy flux, and one way to go at this would be to ask how many photons of light you'd be dealing with. The…
esiegel | June 21, 2013"In any case, the number three fitted perfectly the way quarks occur in nature." -Murray Gell-Mann
You might think that we know it all, at least as far as knowing-it-all is possible. After all, we know that matter is made up of atoms, which are made up of electrons and nuclei, and the nuclei are made up of protons and neutrons, and then the protons and neutrons are made up of quarks and gluons.
Image credit: Hyak / Martin Savage, eScience Institute, University of Washington.
Along with the electrons, the quarks and gluons are -- as far as we know -- indivisible, which places them among the…
drorzel | June 21, 2013One bad thing about SteelyKid's preschool graduation yesterday was that it drained my phone battery, causing me to miss an interview request from a local TV station looking for somebody to talk about a a couple of local guys arrested for a plot to build a "death ray" from X-ray components. This is pretty far from my area of expertise, but, hey, I'd be willing to go on tv and talk about just about anything physics-related. And, as always, I promise to be at least 90% less wrong than Michio Kaku.
Of course, on another level, I'm kind of glad that I didn't get the message in time, because when I…
catdynamics | June 20, 2013Earlier this month I got an invitation to the White House.
It was rather cryptic, asking me to attend an Event, today, followed by a reception in the Indian Treaty Room
Regrettably, I had to decline, I was in Europe, and would only just be getting back. The logistics of getting to DC in time were near impossible; there is no source of funding for such jaunts; and, most important, there was no way I could get the paperwork to be cleared to attend submitted in time.
So, they went ahead without me.
Paul Ginsparg
The Event was the Champions of Change - Open Science edition: a Call for…