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… Continue reading Indirect Excitation Control: Ultrafast Quantum Gates for Single Atomic Qubits
Category: Quantum Optics
Melting Simulated Insulators
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… Continue reading Melting Simulated Insulators
Bunches and Antibunches of Atoms: Hanbury Brown and Twiss Effects in Ultracold Atoms
Two papers in one post this time out. One of these was brought to my attention by Joerg Heber, the other I was reminded of when checking some information for last week’s mathematical post on photons. They fit extremely well together though, and both relate to the photon correlation stuff I was talking about last… Continue reading Bunches and Antibunches of Atoms: Hanbury Brown and Twiss Effects in Ultracold Atoms
High Excitement in Review: “Quantum information with Rydberg atoms”
I’m a big fan of review articles. For those not in academic science, “review article” means a long (tens of pages) paper collecting together the important results of some field of science, and presenting an overview of the whole thing. These vary somewhat in just how specific they are– some deal with both experiment and… Continue reading High Excitement in Review: “Quantum information with Rydberg atoms”
Why Antibunching Equals Photons
In my post about how we know photons exist, I make reference to the famous Kimble, Dagenais, and Mandel experiment showing “anti-bunching” of photons emitted from an excited atom. They observed that the probability of recording a second detector “click” a very short time after the first was small. This is conclusive evidence that photons… Continue reading Why Antibunching Equals Photons
Quantum Optics from the Opposite Direction: QED Limits on Laser Intensities
Most of the time, when we talk about seeing quantum effects from light, we talk about extremely weak beams– looking at intensities where one photon more or less represents a significant change in the intensity of the light. Last week, though, Physics Buzz wrote up a paper that goes in the other direction: they suggest… Continue reading Quantum Optics from the Opposite Direction: QED Limits on Laser Intensities
Do Not Look In Laser Pointer With Remaining Eye
Some folks I used to work with at NIST have looked at cheap green laser pointers, and found a potential danger. Some of the dimmer-looking green lasers are not so dim in the infrared, and in one case emitted 10X the rated power in invisible light. This could be a potential eye hazard. You can… Continue reading Do Not Look In Laser Pointer With Remaining Eye
What’s a Photon, and How Do We Know they Exist?
A reader emailed me with a few questions regarding How to Teach Physics to Your Dog, one of which is too good not to turn into a blog post: What is a photon from an experimental perspective?… Could you perhaps provide me with a reference that discusses some experiments and these definitional issues? The short… Continue reading What’s a Photon, and How Do We Know they Exist?
Quantum Measurement Lotto
Thoreau at Unqualified Offerings gets credit for inspiring two posts today with his proposed Murphy’s Law experiment and this one, about an unrelated issue in quantum measurement. This is an analogy suggested by a colleague a couple of years ago, comparing the projection of a quantum wavefunction in the measurement process to the lottery. The… Continue reading Quantum Measurement Lotto
Murphy Violation in Science
Over at Unqualified Offerings, Thoreau proposes an an experimental test of Murphy’s Law using the lottery. While amusing, it’s ultimately flawed– Murphy’s Law is something of the form: Anything that can go wrong, will. Accordingly, it can only properly be applied to situations in which there is a reasonable expectation of success, unless something goes… Continue reading Murphy Violation in Science