Quantum Optics
drorzel | May 30, 2010Some late nights and wireless problems conspired to keep me from posting anything Friday or Saturday, but I was still at the meeting, and saw some cool talks on coherent X-ray production with lasers, opto-mechanics, and ridiculously good atomic clocks, some of which I hope to talk about later. For the moment, I'm just enjoying being home with Kate and SteelyKid and Emmy, so a real wrap-up post with physics content will have to wait a bit.
I will put up a quick note that I'll be signing books one week from today as part of the Authors Alley program at the World Science Festival. More on that…
drorzel | May 27, 2010Since I sort of implied a series in the previous post, and I have no better ideas, here's a look at Thursday's DAMOP program:
Thursday Morning, 8am (yes, they start having talks at 8am. It's a great trial.)
Session J1 Novel Probes of Ultracold Atom Gases
Chair: David Weiss, Pennsylvania State University Room: Imperial East Invited Speakers: Cheng Chin, Markus Greiner, Kaden Hazzard, Tin-Lun Ho
Session J2 Coherent Control with Optical Frequency Combs
Chair: Linda Young, Argonne National Laboratory Room: Imperial Center Invited Speakers: J. Ye, Moshe Shapiro, W. Campbell, …
drorzel | May 27, 2010I was pretty sedentary on Wednesday, going to only two sessions, and staying for most of the talks in each. I spent most of the initial prize session getting my bearings in the conference areas, and talking to people I know from my NIST days.
In the 10:30 block, I went to the session on Alkaline Earth Quantum Fluids and Quantum Computation. Tom Killian of Rice opened with a nice talk on work his group has done on trapping and Bose condensing several isotopes of strontium; somebody near me pooh-poohed it as just a technical talk on evaporative cooling issues, but I thought Tom did a nice job…
drorzel | May 26, 2010The conference I'm at this week is the annual meeting of the Division of Atomic, Molecular, and Optical Physics of the American Physical Society (which this year is joint with the Canadian version, the Division of Atomic and Molecular Physics and Photon Interactions, or "DAMPΦ." The Greek letter is a recent addition-- as recently as 2001, they were just DAMP.). As the name suggests, this is a meeting covering a wide range of topics, and in some ways is like two or three meetings running in parallel in the same space.
You can see the different threads very clearly if you look at the different…
drorzel | May 24, 2010This is the presentation I gave to the International Baccalaureate class from Schenectady High School today. I tend to re-use talk titles a lot, but this is substantially different than the last talk with this title, as the previous group had read How to Teach Physics to Your Dog first. For this group, I spent more time on applications, and took out a few details.
What Every Dog Should Know About Quantum Physics
View more presentations from Chad Orzel.
We were pressed for time, so I ended up not being able to show the video embedded in the next-to-last slide (this one), which is a shame.…
drorzel | May 10, 2010I've written before about the problem of having in-between views on controversial subjects in blogdom. This is something that also comes up in Jessica's excellent entry on online culture, and has been scientifically demonstrated in political contexts.
I'm somewhat bemused, then, to see the same thing happen in a physics context. A while back, I got an email asking about quantum foundations that read in part:
I'm very keen to understand why you and Andrew Thomas reject [the Many-Worlds Interpretation of QM].
I'd be very happy if you'd take a few minutes to try to describe why you think MWI is…
drorzel | May 9, 2010When I was writing about the seemingly contradictory meanings of "adiabatic" the other day, I almost gave "theory" as an example of a word with nearly opposite meanings. After all, as anyone who has even glanced at the evolution-creation "debate" has heard, a "Theory" in science is something more exalted than a mere guess-- it's a guess that has been confirmed by observations and experiments, and can thus be regarded as true with a high degree of confidence (and assigned a capital letter in this post, to set it apart). (Also, in physical science at least, it makes quantitative predictions.).…
drorzel | May 5, 2010Over at the Virtuosi, there's a nice discussion of the physics of letting air out of tires. Jesse opens the explanation with:
Have you ever noticed how when you let air out of a bike tire (or, I suppose, a car tire) it feels rather cold? Today we're going to explore why that is, and just how cold it is. Many people consider the air escaping from a tire as a classic example of an adiabatic process. What is an adiabatic process? It is a process that happens so quickly there is no time for heat flow to occur. For our air in the bike tire this means we're letting it out of the tire so…
drorzel | May 3, 2010Voting has closed on the Laser Smackdown poll, with 772 people recording their opinion on the most amazing of the many things that have been done with lasers in the fifty years since the invention of the first working laser (see the Laserfest web site for more on the history and applications of lasers). The candidates in the traditional suspense-building reverse order:
Lunar laser ranging 22 votes
Cat toy/ dog toy/ laser light show 41 votes
Laser guide stars/ adaptive optics 46 votes
Holography 47 votes
Laser eye surgery 53 votes
Optical storage media (CD/DVD/Blu-Ray) 60 votes
Laser frequency…
drorzel | April 30, 2010I'm off to Williamstown this afternoon, to talk about research and alsoHow to Teach Physics to Your Dog. If you need blog-based entertainment, though, here are some shiny new radio buttons for you to click:
You're a beam of light: quick, what's your polarization?online survey
I won't offer a personality analysis based on these results, but after enough people vote, we will be able to determine the angle between this blog's readers and the horizontal. So that's something. Of course, it would require several more polls for full quantum state tomography...
(If you're new here, or ok with old…
drorzel | April 30, 2010We're just over 600 votes in the Laser Smackdown poll in honor of the 50th anniversary of the laser, as of early Friday morning. I notice that it has moved off the front page of the blog, though, so here's another signal-boosting repost, just so we have as many votes as possible, to establish maximum scientific validity when we declare the winner the Most Amazing Laser Application of All Time
Which of the following is the most amazing application of a laser?Market Research
Voting will remain open until next Sunday, May 2, just two days from now, with the ultimate winner announced on Monday,…
drorzel | April 28, 2010I'm teaching Physics 350: Quantum Mechanics this term, which is a junior/senior level elective course using Townsend's book which deals with quantum mechanics in the state vector formalism. The room in which the class meets is the only one in the department that contains a whiteboard (using dry-erase markers) rather than a blackboard (using chalk).
In the first several weeks of the course, I have mostly been using blue markers, because that's what's been in the room. These fade into illegibility very quickly, so today I went into the stockroom to get more, and discovered a box of black…
drorzel | April 26, 2010As of 1:45 Monday, 217 people have cast votes in the Laser Smackdown poll. That's not bad, but it's currently being handily beaten by the 271 people who have voted for a favorite system of units.
The nice thing about using actual poll services for this sort of thing, though, is that I can re-post the poll to boost signal a little. So, here it is again, a list of the twelve most amazing laser applications suggested by my wise and worldly readers, with links to short explanations of the pros and cons of each:
Which of the following is the most amazing application of a laser?Market Research…
drorzel | April 23, 2010In 1960, the first working laser was demonstrated, and promptly dubbed "a solution looking for a problem." In the ensuing fifty years, lasers have found lots of problems to solve, but there has been no consensus about which of the many amazing applications of lasers is the most amazing.
Now, in 2010, as we celebrate the anniversary of the laser, we finally have the technology to definitively answer the question: radio-button polls on the Internet!
Which of the following is the most amazing application of a laser?Market Research
Each of the choices above links to a post I wrote here giving you…
drorzel | April 21, 2010What's the application? An optical frequency comb is a short-duration pulsed laser whose output can be viewed as a regularly spaced series of different frequencies. If the pulses are short enough, this can span the entire visible spectrum, giving a "comb" of colored lines on a traditional spectrometer. This can be used for a wide variety of applications, from precision time standards to molecular spectroscopy to astronomy.
What problem(s) is it the solution to? 1) "How do I compare this optical frequency standard to a microwave frequency standard?" 2) "How do I calibrate my spectrometer well…
drorzel | April 13, 2010I'm teaching a junior/senior level elective this term on quantum mechanics. We're using Townsend's A Modern Approach to Quantum Mechanics, which starts with spin-1/2 and develops the whole theory in terms of state vectors and matrices. This is kind of an uneasy fit for me, as I'm very much a swashbuckling experimentalist, and not as comfortable with formal mathematics.
This occasionally leads to good things, though, such as Monday's class, on photon polarizations. the book uses some vector arithmetic to show that circularly polarized photons have spin angular momentum of one unit of h-bar.…
drorzel | April 12, 2010What's the application? LIGO stands for Laser Interferometer Graviitational Wave Observatory, because (astro)physicists feel free to drop inconvenient words when making up cute acronyms. This is an experiment to look for disturbances in space-time caused by massive objects, which would manifest as a slight stretching and compression of space itself.
What problem(s) is it the solution to? 1) "Can we directly observe the gravitational waves that are predicted by the equations of General Relativity?" 2) "Can we detect things like colliding black holes, because that would be awesome!"
How does it…
drorzel | March 24, 2010Several people have sent me links to news stories about last week's Nature paper, "Quantum ground state and single-phonon control of a mechanical resonator." (It was also presented at the March Meeting, but I didn't go to that session). This is billed as the first observation of quantum phenomena with a "macroscopic" or "naked eye visible" object.
Of course, there's a nice bit of irony in a story about quantum effects in a "naked eye visible" object that is accompanied by an image of the object in question taken with a scanning electron microscope. The longest dimension of the object in…
drorzel | March 15, 2010I'm terrible about taking notes on conference talks, especially when I'm jet-lagged and was sleep deprived even before I got on the plane. I do jot down the occasional paper reference, though, so here are the things I wrote down, and the talks they were associated with. This should give you some vague idea of what the meeting was like on Monday.
From Joel Moore's talk on topological insulators, one of the Hot New Topics in condensed matter, a review in Nature.
From Phillip Treutlein's talk on optomechanics, a recent preprint on coupling atoms to mechanical oscillators.
From Nathaniel Brahms's…
drorzel | February 12, 2010There have been a bunch of stories recently talking about quantum effects at room temperature-- one, about coherent transport in photosynthesis , even escaped the science blogosphere. They've mostly said similar things, but Thursday's ArxivBlog entry had a particular description of a paper about entanglement effects that is worth unpacking:
Entanglement is a strange and fragile thing. Sneeze and it vanishes. The problem is that entanglement is destroyed by any interaction with the environment and these interactions are hard to prevent. So physicists have only ever been able to study and…