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Tiniest Lamp Spans Quantum, Classical Physics
Urchin writes "Physicists in California have made the smallest ever incandescent lamp using a carbon nanotube as the filament. The nanotube is so small it behaves as a quantum mechanical system but it's just large enough that the classical physics rules of thermodynamics should apply. Analyzing the light emitted from the tiny light will give the team a better picture of what happens in the twilight zone between the quantum and classical worlds." The New Scientist article doesn't mention the researchers' surprise, as the abstract does: "Remarkably, the heat equation and Planck's law together give a precise, quantitative description of the light intensity as a function of input power, even though the nanotube's small size places it outside the thermodynamic limit."
I'm sorry - but they will have to switch it out for a really tiny compact fluorescent bulb.
..........FULL STOP.
Obviously. Which isn't to say that the concept of a classical regime versus a quantum one isn't useful. You wouldn't describe the motion of a baseball using Schroedinger's equation: it's perfectly possible, but impractical.
Any information we can get about the transition between the two regimes is very valuable indeed.
The state you are in while your HEAD is detached... - wait, what?
How many quantum physicists does it take to change a light bulb?
One. Two to do it, and one to renormalise the wave function.
"Trolls they were, but filled with the evil will of their master: a fell race..." -- J.R.R. Tolkien on Olog-hai
Obviously. Which isn't to say that the concept of a classical regime versus a quantum one isn't useful. You wouldn't describe the motion of a baseball using Schroedinger's equation: it's perfectly possible, but impractical.
Good point. I was browsing Douglas Hofstadter's I Am a Strange Loop recenlty, and he made a great point about levels of description. He notes that when we discover "X is reducible to the more fundamental phenomenon of Y", people seem to think that means Y is more important and useful. But, he says, that discovery is equivalent to "Y can be ignored at the level X". That is, even though there might be a lower-level description, the discovery of enough regularity at that level is also useful since it means a simpler way to describe what's going on.
Information theory is life. The rest is just the KL divergence.
This experiment is important because it reveals something about physics. However, I wonder if this could also lead to practical inventions. Could a high intensity energy efficient light bulb be made from millions of tiny nanolamps clumped together?
I just replaced all the lamps in my house with these, but they just don't seem to brighten up the room like the old ones, and now my cat is missing.
The things we must endure for global warming to be a success.
Who would win this election: Andrew Weiner vs Andrew Weiner's weiner.
Reading Beowulf under the light provided by a cluster of these lamps!
The history of science suggests that exploring the intersection of two bodies of theory is a very important kind of experiment. It was Thomas Young's double slit experiments, Planck's study of blackbody radiation, and Einstein's work with the photoelectric effect that revealed the necessary clues to the quantum theory that resolved the paradox of the apparent wave/particle duality of electromagentic radiation.
It took 19th century classical physicists an entire century to resolve this issue, so long that the discipline became a little stagnant and some folks were beginning to claim that physics had explained everything there was to explain. However, Planck's work was especially important in revealing the quantized energy nature of light that was the key to opening up 20th century physics.
Anyway, to keep this short, I suggest that we find ourselves in a similar situation. Our current models have been played out, and are leaving a lot of important questions unanswered. There are a few candidate theories that hold promise but aren't supported by observations. Looking at the cracks between our building blocks worked before -- it opened up whole universes of possiblility. We need to keep doing it. This experiment is a great example of that kind of work.
I can see the fnords!