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Tiniest Lamp Spans Quantum, Classical Physics 59

Posted by kdawson
from the just-small-enough dept.
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."
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Tiniest Lamp Spans Quantum, Classical Physics

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  • New lightbulb? (Score:3, Interesting)

    by nausea_malvarma (1544887) on Friday May 01, 2009 @11:13AM (#27787279)
    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?
  • by Anonymous Coward on Friday May 01, 2009 @11:53AM (#27788005)
    Your statement is true about all physical laws. They are just rules that work well enough to predict events, but that doesn't mean they are whats really happening.
  • by wdef (1050680) on Saturday May 02, 2009 @04:16AM (#27796871)

    You would simply be aware (insofar as awareness might be possible in such a universe) that the various components of wavefunctions decohere smoothly over time due to interactions and entanglements with systems

    Actually, a very great and quite under appreciated physicist, HS ("Bert") Green, did show with colleagues that this collapse does occur just because of the interaction between systems and that mathematically it is not the least bit mysterious or spooky. Why the name of this man, who Max Born called "brilliant", is not better known has to be the real mystery.

    See http://www.science.org.au/academy/memoirs/green.htm [science.org.au]

    In 1958 Bert published one of his best papers [53]. It was entitled 'Observation in Quantum Mechanics' and addressed one of the outstanding problems of modern physics, namely the process by which indeterminate superpositions in quantum mechanics become converted to the determinate, although possibly unknown, alternatives of ordinary macroscopic physics. For many years the prescription of von Neumann, usually called the 'collapse of the wave packet', was the accepted view of how this happened. As it assumed that some processes outside quantum mechanics had to be invoked, even going so far as involving the brain of the human observer, people were not comfortable with it, although it seemed the only possible answer. The best known representation of this difficulty appears in the well-known SchrÃdinger's cat paradox. Bert, together with a number of others such as Wakita and Ludwig, found a much more satisfying explanation, which is basically still the received description, although nowadays in various forms. The idea was to suppose that a measuring apparatus could be of almost any form so long as it was very complicated, that is, contained a very large number (often for mathematical convenience taken to be infinite) of components such as molecules or electrons. The system being measured could be microscopic. When the two systems interact, any 'interference terms' in the state of the microscopic system become vanishingly small purely as a consequence of the size of the measuring instrument. There are, of course, many processes in nature in which a human observer is not involved â" especially before homo sapiens evolved â" and the von Neumann description is quite unable to say how these could happen. However with Bert's theory all one has to do is to replace the measuring apparatus by the environment to bring about the necessary disappearance of interferences. The only place where this very satisfactory explanation might run into some difficulty is in the early evolution of the universe, where there is no environment!

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