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Chad Orzel
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  • September 24, 2011
  • 07:43 PM

Faster Than a Speeding Photon: "Measurement of the neutrino velocity with the OPERA detector in the CNGS beam"

by Chad Orzel in Uncertain Principles

There have been a lot of pixels spilled over this faster-than-light neutrino business, so it might not seem like something I should take time away from pressing work to write up. It is the story of the moment, though, and too much of the commentary I've seen has been of the form "I am a {theorist, journalist} so hearing about experimental details gives me the vapors" (a snarky paraphrase, obviously). This suggests that there's still room for a canine-level write-up going into a bit more depth ab........ Read more »

The OPERA Collaboraton: T. Adam, N. Agafonova, A. Aleksandrov, O. Altinok, P. Alvarez Sanchez, S. Aoki, A. Ariga, T. Ariga, D. Autiero, A. Badertscher.... (2011) Measurement of the neutrino velocity with the OPERA detector in the CNGS beam. CERN. arXiv: 1109.4897v1

  • September 6, 2011
  • 11:48 AM

Quantum Computing with Microwaves

by Chad Orzel in Uncertain Principles

It's been a while since I did any ResearchBlogging, first because I was trying to get some papers of my own written, and then because I was frantically preparing for my classes this term (which start Wednesday). I've piled up a number of articles worth writing up in that time, including two papers from an early-August issue of Nature, on advances in experimental quantum computation (the first is available as a free pdf because it was done at NIST, and thus is not copyrightable). These were also ........ Read more »

Ospelkaus, C., Warring, U., Colombe, Y., Brown, K., Amini, J., Leibfried, D., & Wineland, D. (2011) Microwave quantum logic gates for trapped ions. Nature, 476(7359), 181-184. DOI: 10.1038/nature10290  

Timoney, N., Baumgart, I., Johanning, M., Varón, A., Plenio, M., Retzker, A., & Wunderlich, C. (2011) Quantum gates and memory using microwave-dressed states. Nature, 476(7359), 185-188. DOI: 10.1038/nature10319  

  • August 23, 2011
  • 12:54 PM

The Dubious Science of Teacher Coaching: "An Interaction-Based Approach to Enhancing Secondary School Instruction and Student Achievement"

by Chad Orzel in Uncertain Principles

A while back, I Links Dumped Josh Rosenau's Post Firing Bad Teachers Doesn't Create good Teachers, arguing that rather than just firing teachers who need some improvement, schools should look at, well, helping them improve. This produced a bunch of scoffing in a place I can't link to, basically taking the view that people are either good at what they do, or they're not, and if they're not, you just fire them and hire somebody else. I was too busy to respond at the time, but marked that doen as s........ Read more »

  • July 26, 2011
  • 12:34 PM

The Physics of Frustration: "Quantum Simulation of Frustrated Classical Magnetism in Triangular Optical Lattices"

by Chad Orzel in Uncertain Principles

One of the benefits of having joined AAAS in order to get a reduced registration fee at their meeting is that I now have online access to Science at home. Including the Science Express advance online papers, which I don't usually get on campus. Which means that I get the chance to talk about the few cool physics things they post when they first become available, without having to beg for a PDF on Twitter. This week's advance online publication list includes a good example of the sort of coolultr........ Read more »

Struck, J., Olschlager, C., Le Targat, R., Soltan-Panahi, P., Eckardt, A., Lewenstein, M., Windpassinger, P., & Sengstock, K. (2011) Quantum Simulation of Frustrated Classical Magnetism in Triangular Optical Lattices. Science. DOI: 10.1126/science.1207239  

  • July 12, 2011
  • 01:34 PM

It's Magnetic Moment Season: Measuring Various g-Factors

by Chad Orzel in Uncertain Principles

Among the articles highlighted in this week's Physics is one about a new test of QED through a measurement of the g-factor of the electron in silicon ions. This comes on the heels of a measurement of proton spin flips (this includes a free PDF) a couple of weeks ago, and those, in turn, build on measurements of electrons from a few years back, which Jerry Gabrielse talked about at DAMOP. Evidently, it's magnetic moment season in the world of physics.

The media reports on the proton experiment t........ Read more »

Sturm, S., Wagner, A., Schabinger, B., Zatorski, J., Harman, Z., Quint, W., Werth, G., Keitel, C., & Blaum, K. (2011) g Factor of Hydrogenlike ^{28}Si^{13 }. Physical Review Letters, 107(2). DOI: 10.1103/PhysRevLett.107.023002  

Ulmer, S., Rodegheri, C., Blaum, K., Kracke, H., Mooser, A., Quint, W., & Walz, J. (2011) Observation of Spin Flips with a Single Trapped Proton. Physical Review Letters, 106(25). DOI: 10.1103/PhysRevLett.106.253001  

  • June 7, 2011
  • 11:58 AM

Commanding the Power of Thor...ium: "Wigner Crystals of 229Th for Optical Excitation of the Nuclear Isomer"

by Chad Orzel in Uncertain Principles

I have to admit, I'm writing this one up partly because it lets me use the title reference. It's a cool little paper, though, demonstrating the lengths that physicists will go to in pursuit of precision measurements.

I'm just going to pretend I didn't see that dorky post title, and ask what this is about. Well, it's about the trapping and laser cooling of thorium ions. They managed to load thorium ions into an ion trap, and use lasers to lower their temperature into the millikelvin range. At su........ Read more »

  • June 3, 2011
  • 11:37 AM

Watching Photons Interfere: "Observing the Average Trajectories of Single Photons in a Two-Slit Interferometer"

by Chad Orzel in Uncertain Principles

An explanation of a Science paper on using weak measurements to trace the average trajectories of photons in a double-slit interference experiment.... Read more »

Sacha Kocsis, Boris Braverman, Sylvain Ravets, Martin J. Stevens, Richard P. Mirin, L. Krister Shalm, & Aephraim M. Steinberg. (2011) Observing the Average Trajectories of Single Photons in a Two-Slit Interferometer. Science, 332(6034), 1179-1173. info:/10.1126/science.1202218

  • May 27, 2011
  • 12:02 PM

What Goes Around Is Really Round: "Improved measurement of the shape of the electron"

by Chad Orzel in Uncertain Principles

The 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 st........ Read more »

Hudson, J., Kara, D., Smallman, I., Sauer, B., Tarbutt, M., & Hinds, E. (2011) Improved measurement of the shape of the electron. Nature, 473(7348), 493-496. DOI: 10.1038/nature10104  

  • May 16, 2011
  • 12:31 PM

Active Engagement Works: "Improved Learning in a Large-Enrollment Physics Class"

by Chad Orzel in Uncertain Principles

Physics is a notoriously difficult and unpopular subject, which is probably why there is a large and active Physics Education Research community within physics departments in the US. This normally generates a lot of material in the Physical Review Special Topics journal, but last week, a PER paper appeared in Science, which is unusual enough to deserve the ResearchBlogging treatment.

OK, what's this paper about? Well, with the exceptional originality that physicists bring to all things, the tit........ Read more »

Deslauriers, L., Schelew, E., & Wieman, C. (2011) Improved Learning in a Large-Enrollment Physics Class. Science, 332(6031), 862-864. DOI: 10.1126/science.1201783  

  • May 9, 2011
  • 11:49 AM

On the "Hot Hand" in Basketball

by Chad Orzel in Uncertain Principles

A little while back, Jonah Lehrer did a nice blog post about reasoning that used the famous study by Gilovich, Vallone and Tversky, The Hot Hand in Basketball (PDF link) as an example of a case where people don't want to believe scientific results. The researchers found absolutely no statistical evidence of "hot" shooting-- a player who had made his previous couple of shots was, if anything, slightly less likely to make the next one. Lehrer writes:

Why, then, do we believe in the hot hand? Con........ Read more »

  • May 2, 2011
  • 11:55 AM

Proving Einstein Wrong...ish: Measurement of the Instantaneous Velocity of a Brownian Particle

by Chad Orzel in Uncertain Principles

Last summer, there was a fair bit of hype about a paper from Mark Raizen's group at Texas which was mostly reported with an "Einstein proven wrong" slant, probably due to this press release. While it is technically true that they measured something Einstein said would be impossible to measure, that framing is a little unfair to Einstein. It does draw media attention, though...

The experiment in question involves Brownian motion, and since I had to read up on that anyway for something else, I th........ Read more »

Li, T., Kheifets, S., Medellin, D., & Raizen, M. (2010) Measurement of the Instantaneous Velocity of a Brownian Particle. Science, 328(5986), 1673-1675. DOI: 10.1126/science.1189403  

  • April 26, 2011
  • 12:36 PM

Treating Photons Like Atoms: "Bose-Einstein condensation of photons in an optical microcavity"

by Chad Orzel in Uncertain Principles

This paper made a big splash back in November, with lots of news stories talking about it; it even made the #6 spot on Physics World's list of breakthroughs of the year. I didn't write it up then because I was hellishly busy, and couldn't take time away from working on the book-in-progress to figure out exactly what they did and why it mattered. I've got a little space now between handing the manuscript in last week and starting to revise it (probably next week), so while it's a bit late, here's........ Read more »

Klaers, J., Schmitt, J., Vewinger, F., & Weitz, M. (2010) Bose–Einstein condensation of photons in an optical microcavity. Nature, 468(7323), 545-548. DOI: 10.1038/nature09567  

  • April 21, 2011
  • 12:17 PM

Bouncing Neutrons for Fun and Science: "Realization of a gravity-resonance-spectroscopy technique"

by Chad Orzel in Uncertain Principles

Several people blogged about a new measurement of gravitational states of neutrons done by physicists using ultracold neutrons from the Institut Laue-Langevin in France. I had to resort to Twitter to get access to the paper (we don't get Nature Physics here, and it's way faster than Inter-Library Loan), but this is a nice topic for a ResearchBlogging post, in the now-standard Q&A form:

OK, why was this worth begging people on Twitter to send you a copy? The paper is a demonstration of a sor........ Read more »

Jenke, T., Geltenbort, P., Lemmel, H., & Abele, H. (2011) Realization of a gravity-resonance-spectroscopy technique. Nature Physics. DOI: 10.1038/nphys1970  

Nesvizhevsky, V., Börner, H., Petukhov, A., Abele, H., Baeßler, S., Rueß, F., Stöferle, T., Westphal, A., Gagarski, A., Petrov, G.... (2002) Quantum states of neutrons in the Earth's gravitational field. Nature, 415(6869), 297-299. DOI: 10.1038/415297a  

  • April 18, 2011
  • 11:35 AM

Wave Nature Gets Bigger: "Quantum interference of large organic molecules"

by Chad Orzel in Uncertain Principles

It's been a while since I wrote up a ResearchBlogging post, but since a recent paper forced me to update my "What Every Dog Should Know About Quantum Physics" slides with new pictures, I thought I should highlight the work on the blog as well. Not that you could've missed it, if you follow physics-y news-- it's been all over, getting almost as much press as rumors that some people whose funding will run out soon saw something intriguing in their data. So, in the usual Q&A format:

OK, what'........ Read more »

Gerlich, S., Eibenberger, S., Tomandl, M., Nimmrichter, S., Hornberger, K., Fagan, P., Tüxen, J., Mayor, M., & Arndt, M. (2011) Quantum interference of large organic molecules. Nature Communications, 263. DOI: 10.1038/ncomms1263  

Hornberger, K., Gerlich, S., Ulbricht, H., Hackermüller, L., Nimmrichter, S., V Goldt, I., Boltalina, O., & Arndt, M. (2009) Theory and experimental verification of Kapitza–Dirac–Talbot–Lau interferometry. New Journal of Physics, 11(4), 43032. DOI: 10.1088/1367-2630/11/4/043032  

  • November 19, 2010
  • 11:38 AM

Interference of Independent Photon Beams: The Pfleegor-Mandel Experiment

by Chad Orzel in Uncertain Principles

Earlier this week, I talked about the technical requirements for taking a picture of an interference pattern from two independent lasers, and mentioned in passing that a 1967 experiment by Pfleegor and Mandel had already shown the interference effect. Their experiment was clever enough to deserve the ResearchBlogging Q&A treatment, though, so here we go:

OK, so why is this really old experiment worth talking about? What did they do? They demonstrated interference between two completely inde........ Read more »

Pfleegor, R., & Mandel, L. (1967) Interference of Independent Photon Beams. Physical Review, 159(5), 1084-1088. DOI: 10.1103/PhysRev.159.1084  

  • November 17, 2010
  • 04:48 PM

Trapped Antihydrogen

by Chad Orzel in Uncertain Principles

The big physics-y news story of the moment is the trapping of antihydrogen by the ALPHA collaboration at CERN. The article itself is paywalled, because this is Nature, but one of the press offices at one of the institutions involved was kind enough to send me an advance version of the article. This seems like something that deserves the ResearchBlogging Q&A treatment, so here we go:

OK, what's the deal with this paper? Well, the ALPHA collaboration is announcing that they have created antih........ Read more »

Andresen, G., Ashkezari, M., Baquero-Ruiz, M., Bertsche, W., Bowe, P., Butler, E., Cesar, C., Chapman, S., Charlton, M., Deller, A.... (2010) Trapped antihydrogen. Nature. DOI: 10.1038/nature09610  

  • November 12, 2010
  • 01:51 PM

Relativity on a Human Scale: "Optical Clocks and Relativity"

by Chad Orzel in Uncertain Principles

As mentioned in yesterday's post on ion trapping, a month or so back Dave Wineland's group at NIST published a paper in Science on using ultra-precise atomic clocks to measure relativistic effects. If you don't have a subscription to Science, you can get the paper for free from the Time and Frequency Division database, because you can't copyright work done for the US government.

This paper generated quite a bit of interest when it came out, because it demonstrates the time-slowing effects of re........ Read more »

Chou, C., Hume, D., Rosenband, T., & Wineland, D. (2010) Optical Clocks and Relativity. Science, 329(5999), 1630-1633. DOI: 10.1126/science.1192720  

Schmidt, P. (2005) Spectroscopy Using Quantum Logic. Science, 309(5735), 749-752. DOI: 10.1126/science.1114375  

  • August 30, 2010
  • 01:49 PM

Indirect Excitation Control: Ultrafast Quantum Gates for Single Atomic Qubits

by Chad Orzel in Uncertain Principles

Last week, John Baez posted a report on a seminar by Dzimitry Matsukevich on ion trap quantum information issues. In the middle of this, he writes:

Once our molecular ions are cold, how can we get them into specific desired states? Use a mode locked pulsed laser to drive stimulated Raman transitions.

Huh? As far as I can tell, this means "blast our molecular ion with an extremely brief pulse of light: it can then absorb a photon and emit a photon of a different energy, while itself jumping to ........ Read more »

Campbell, W., Mizrahi, J., Quraishi, Q., Senko, C., Hayes, D., Hucul, D., Matsukevich, D., Maunz, P., & Monroe, C. (2010) Ultrafast Gates for Single Atomic Qubits. Physical Review Letters, 105(9). DOI: 10.1103/PhysRevLett.105.090502  

  • August 26, 2010
  • 01:42 PM

Measuring Gravity: Ain't Nothin' but a G Thing

by Chad Orzel in Uncertain Principles

There's a minor scandal in fundamental physics that doesn't get talked about much, and it has to do with the very first fundamental force discovered, gravity. The scandal is the value of Newton's gravitational constant G, which is the least well known of the fundamental constants, with a value of 6.674 28(67) x 10-11 m3 kg-1 s-2. That may seem pretty precise, but the uncertainty (the two digits in parentheses) is scandalously large when compared to something like Planck's constant at 6.626 068 9........ Read more »

Schlamminger, S., Holzschuh, E., Kündig, W., Nolting, F., Pixley, R., Schurr, J., & Straumann, U. (2006) Measurement of Newton’s gravitational constant. Physical Review D, 74(8). DOI: 10.1103/PhysRevD.74.082001  

Luo, J., Liu, Q., Tu, L., Shao, C., Liu, L., Yang, S., Li, Q., & Zhang, Y. (2009) Determination of the Newtonian Gravitational Constant G with Time-of-Swing Method. Physical Review Letters, 102(24). DOI: 10.1103/PhysRevLett.102.240801  

Harold V. Parks, & James E. Faller. (2010) A Simple Pendulum Determination of the Gravitational Constant. Physical Review Letters (accepted). arXiv: 1008.3203v2

  • August 25, 2010
  • 10:38 AM

Melting Simulated Insulators

by Chad Orzel in Uncertain Principles

The Joerg Heber post that provided one of the two papers for yesterday's Hanbury Brown Twiss-travaganza also included a write-up of a new paper in Nature on Mott insulators, which was also written up in Physics World.

Most of the experimental details are quite similar to a paper by Markus Greiner's group I wrote up in June: They make a Bose-Einstein Condensate, load it into an optical lattice, and use a fancy lens system to detect individual atoms at sites of the lattice. This lattice can be pr........ Read more »

Sherson, J., Weitenberg, C., Endres, M., Cheneau, M., Bloch, I., & Kuhr, S. (2010) Single-atom-resolved fluorescence imaging of an atomic Mott insulator. Nature. DOI: 10.1038/nature09378  

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