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Particle-Wave Duality Demonstrated With Largest Molecules Yet
An anonymous reader tips news that researchers have successfully demonstrated particle-wave duality in molecules that have masses of 514 and 1,298 atomic mass units. The academic paper can be found in Nature Nanotechnology.
"Thomas Juffmann et al. fired molecules composed of over 100 atoms at a barrier with openings designed to minimize molecular interactions, and observed the build-up of an interference pattern. The experiment approaches the regime where macroscopic and quantum physics overlap, offering a possible way to study the transition that has frustrated many scientists for decades. ... The relatively large phthalocyanine (C32H18N8) and derivative molecules (C48H26F24N8O8) have more mass than anything in which quantum interference has previously been observed. To have wavelengths that are relatively large compared to their sizes, the molecules need to move very slowly. Juffmann et al. achieved this by directing a blue diode laser onto a very thin film of molecules in a vacuum chamber, effectively boiling off individual molecules directly under the beam while leaving the rest unaffected. ... The researchers observed the particle nature of the molecules in the form of individual light spots appearing singly in the fluorescent detector as they arrived. But, over time, these spots formed an interference pattern due to the molecules' wavelike character.'"
The mentioned researchers in Vienna created this movie where you see both the particle nature as well as the interference pattern:
https://www.youtube.com/watch?v=vCiOMQIRU7I
NB: The message above might reflect my opinion right now, but not necessarily tomorrow or next year.
Yes and no.
I do not believe in particle-wave duality. I believe in Feynman's path integral formulation.
http://en.wikipedia.org/wiki/Path_integral_formulation
Read QED if you want to know more of this.
http://en.wikipedia.org/wiki/QED:_The_Strange_Theory_of_Light_and_Matter
Using path integral a particle does not need to interference itself in order to produce the interference pattern.
Government cannot make man richer, but it can make him poorer. - Ludwig von Mises
Scientists are currently trying, albeit with somewhat smaller objects than a person. What you should understand is that the tunneling probability is exponentially damped in both the width of the barrier and the size of the object.
Already for a hydrogen nucleus tunneling through the (electrostatic) potential barrier presented by another hydrogen nucleus, the probability is around 10^-30 (if memory serves correctly). This fact is what keeps the sun burning for billions of years, and not exploding like a hydrogen bomb in a split second, since it limits the rate of fusion processes in the sun.
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This should happen with everything, it just happens to be that larger objects are going to very difficult to isolate from noise (which causes "decoherence"). What is impressive about this experiment is the degree to which the experimentalists were able to isolate this system from external interference (and move them so slowly), not that larger objects happen to exhibit QM properties (this is completely expected).
It would be very difficult to test DNA in the manner described in the paper- it would appear that the specific molecules chosen have a number of attributes that make them suitable for the double-slit experiment. They are fluorescent dyes, which makes them very sensitive to detection, they can be vaporized without thermal decomposition, they are neutral molecules, and they have multiple symmetries so that there isn't a preferred orientation. DNA molecules would be destroyed by the heat sources they used, and the highly charged DNA molecule is likely to interact with the atoms of the diffraction grating in a classical electrostatic manner. Some other biomolecules might be more suitable- phthalocyanine is similar in structure to heme and chlorophyll.
"FDA staff reviewers expressed concern about the number of patients who were left out of the study because they died."
Maybe you thought that.
Among the last few generations of physicists it is generally believed that everything is quantum from an elementary particle to whole planets. It's just very difficult to cool planets down to where the thermal length is smaller than their de Broglie's length. Not to mention creating a coherent planet gun and detector... But there was no reason to believe it is fundamentally impossible.
Wave-particle duality has yet been observed with much bigger objects, on different physical basis but with astonishingly equivalent behaviour.
A 'walking' drop on a liquid surface behave like a particle with wave properties: diffraction, interference patterns, vibration quantization.
First, in a vibrating container they put a liquid like silicon oil, vibrations are just bellow the Faraday instability threshold. Then a drop of the same liquid is dropped on the surface, but it does not coalesce, it bounces. And further bounces make a static wave pattern on the liquid surface just bellow the drop and its immediate neighborhood. As the spike grows, instability increases and the drop slides down the spike, and start moving horizontally.
Then they have a combo object drop+wave pattern moving at 1/10th the speed of wave in this liquid, straight. They call it a walker.
What is really amazing is that the wave pattern below the drop has some kind of memory: it has accumulated energy from several drop bounces. It can also make the drop see "forward", as the small wave pattern bounces back from nearby obstacles. So the drop is "aware" of its environment and "recall" the path it has followed.
Diffraction is observed and explained by the multiple reflexions the wave makes when the drop passes through a small hole, randomizing the wave pattern and the angle of the path afterward. Interference patterns observed are explained a la de Broglie: as the drop passes through one of the two holes, its associated wave passes through both, carrying forward the message of the second hole to the drop and changing the statistical repartition of the drop's path direction. One more stunning result: they are circling the drop by moving the container (Coriolis), then the associated wave adopts a discrete series of pattern, depending on the speed and radius. Very much like the energy quantization of electrons.
English (and French) abstract
A short article (French but it has photos and formulas)
Full thesis (French,10Mb)"
Alright, let me clarify what I meant. In fusion, the main factors in determining the reaction speed is the energy and the density. While the energy is comparable in the sun and a hydrogen bomb, the density is 2 orders of magnitude higher in a hydrogen bomb than at the sun's core. The tunneling probability is exponentially sensitive to the density; so sensitive that a third of the way out from the sun's core, fusion can no longer happen. This means that those 2 orders of magnitude are translated into 20 orders of magnitude slower explosion. At that point, I wouldn't call it an explosion.
Just to highlight this point: the power production per volume at the sun's core is 280 W/m^3. This is less than for a human being, it's roughly the same power as a crocodile produces per volume.
TL;DR: You're saying that the smoldering pile of flour on my kitchen bench is exactly like a dust explosion. I beg to differ.
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I can only shoot my DNA at a single slit target. My wife would never go for a multiple slit experiment.
This issue is a bit more complicated than you think.