What Does “Negative Temperature” Mean, Anyway?

The most talked-about physics paper last week was probably Negative Absolute Temperature for Motional Degrees of Freedom (that link goes to the paywalled journal; there’s also a free arxiv preprint from which the above figure is taken). It’s a catchy but easily misinterpreted title– Negative absolute temperature! Below Absolute Zero! Thermodynamics is wrong!– that obscures […]

Using Light to Put a Mirror in the Dark: “Optomechanical Dark Mode”

In which I unpack a cryptic paper title and explain how quantum superposition lets you use light to keep things from interacting with light. ————- I joined AAAS a couple of years ago to get a break on the registration fee for their meeting, and I’ve kept up the membership mostly because I like having […]

Apparatus for entangling two photons that never coexist.

Entangled in the Past: “Entanglement Between Photons that have Never Coexisted”

In which we do a little ResearchBlogging to look at a new paper about weird quantum effects, entangling two photons that never both exist at the same time. ———— I’m teaching full-time this term, but I’ve blocked out Thursdays as a day when I don’t do class- or chair-related work. Usually, this means trying to […]

Figure 2

Simulating Wires with Atoms and Light: “Conduction of Ultracold Fermions Through a Mesoscopic Channel”

So, it’s been a while, but let’s see if we can’t hit the ground running with a good physics post. There have been a few notable physics events since I went on hiatus, but for a return to physics ResearchBlogging, we’ll go with something near and dear to my heart, ultracold atoms. Specifically, this Science […]

Color diagram of the final beamsplitter in an atom interferometer.

The Towering Interferometer: “Testing General Relativity with Atom Interferometry”

In which we look at a slightly crazy-sounding proposal from my former boss, the experimental realization of which is getting close to completion. ———— I spent more or less the entire first day of DAMOP a couple of weeks ago going to precision measurement talks. Most of these were relatively sedate (at least by the […]

Experimental apparatus for the double-slit with a two-lobed laser mode.

Single Photons Are Still Photons: “Wave-particle dualism and complementarity unraveled by a different mode”

In which we do a little ResearchBlogging, taking a look at a slightly confusing paper putting a new twist on the double-slit experiment. ———— I’m off to California this afternoon, spending the rest of the week at DAMOP in Pasadena (not presenting this year, just hanging out to see the coolest new stuff in Atomic, […]

Entangled In the Past: “Experimental delayed-choice entanglement swapping”

Enough slagging of beloved popularizers– how about some hard-core physics. The second of three extremely cool papers published last week is this Nature Physics paper from the Zeilinger group in Vienna, producers of many awesome papers about quantum mechanics. Ordinarily, this would be a hard paper to write up, becase Nature Physics are utter bastards, […]

Clock Synchronization Done Right: “A 920-Kilometer Optical Fiber Link for Frequency Metrology at the 19th Decimal Place”

I’ve been busily working on something new, but I’m beginning to think I’ve been letting the perfect be the enemy of the good-enough-for-this-stage, so I’m setting it aside for a bit, and trying to get caught up with some of the huge number of things that have been slipping. Which includes getting the oil changed […]

Treating Big Molecules Like Electrons: “Real-time single-molecule imaging of quantum interference”

Richard Feyman famously once said that the double-slit experiment done with electrons contains everything that’s “‘at the heart of quantum physics.” It shows both particle and wave character very clearly: the individual electrons are detected one at a time, like particles, but the result of a huge number of detections clearly traces out an interference […]

Shedding Light on Quantum Gravity: “Probing Planck-scale physics with quantum optics”

It’s been a while since I did any ResearchBlogging posts, because it turns out that having an infant and a toddler really cuts into your blogging time. Who knew? I keep meaning to get back to it, though, and there was a flurry of excitement the other day about a Nature Physics paper proposing a […]