Monday, May 20, 2024

4474 - ATOMS - have wave particle duality?

 

-  4474   -  ATOMS  -  have wave particle duality?  -   Atoms squished closer together than ever before, revealing seemingly impossible “quantum effects”.   Using a  laser technique, scientists have squished pairs of atoms closer together than ever before, revealing some truly mind-boggling quantum effects.


-------------------------------  4474    -    ATOMS  -  have wave particle duality?

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-   Scientists have two atoms interacting at an extremely close separation. They pushed layers of atoms 10 times closer together than in any previous experiment, resulting in odd quantum effects.

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-    The squished two layers of ultracold magnetic atoms are within 50 nanometers of each other.  This is 10 times closer than in previous experiments.  It revealing bizarre quantum effects not seen before.

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-   The extreme proximity of these atoms will allow researchers to study quantum interactions at this length scale for the first time and could lead to important advances in the development of superconductors and quantum computers.

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-    Unusual quantum behaviors begin to emerge at ultracold temperatures as the atoms are forced to occupy their lowest possible energy state.  In the nanokelvin regime, there's a type of matter called “Bose Einstein condensate” in which all the particles behave like waves. They are basically quantum mechanical objects.

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-    Interactions between these isolated systems are particularly important for understanding quantum phenomena such as superconductivity and superradiance. But the strength of these interactions typically depends on the separation distance, which can create practical problems for researchers studying these effects; their experiments are limited by how close they can get the atoms.

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-    Most atoms used in cold experiments, such as the alkali metals, have to have contact in order to interact.    We're interested in 'dysprosium atoms' which are special in that they can interact with each other at long range through dipole-dipole interactions weak attractive forces between partial charges on adjacent atoms.   But although there's this long-range interaction, there are still some types of quantum phenomena that cannot be realized because this dipole interaction is so weak.

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-     Bringing cold atoms into close proximity while maintaining control of their quantum states is a significant challenge, and until now, experimental limitations have prevented researchers from fully testing theoretical predictions about the effects of these quantum interactions.

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-    For the first time ever, physicists have captured a clear image of individual atoms behaving like a wave.  The image shows sharp red dots of fluorescing atoms transforming into fuzzy blobs of wave packets and is a stunning demonstration of the idea that atoms exist as both particles and waves one of the cornerstones of quantum mechanics.

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-    The wave nature of matter remains one of the most striking aspects of quantum mechanics. First proposed by the French physicist Louis de Broglie in 1924 and expanded upon by Erwin Schrödinger two years later, “wave particle duality” states that all quantum-sized objects, and therefore all matter, exists as both particles and waves at the same time.   Schrödinger's famous equation is typically interpreted by physicists as stating that atoms exist as packets of wave-like probability in space, which are then collapsed into discrete particles upon observation. While bafflingly counterintuitive, this bizarre property of the quantum world has been witnessed in numerous experiments.

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-    To image this fuzzy duality, the physicists first cooled lithium atoms to near-absolute zero temperatures by bombarding them with photons, or light particles, from a laser to rob them of their momentum. Once the atoms were cooled, more lasers trapped them within an optical lattice as discrete packets.

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-    With the atoms cooled and confined, the researchers periodically switched the optical lattice off and on expanding the atoms from a confined near-particle state to one resembling a wave, and then back.

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-    A microscope camera recorded light emitted by atoms in the particle state at two different times, with atoms behaving like waves in between. By putting together many images, the authors built up the shape of this wave and observed how it expands with time, in perfect agreement with Schrödinger's equation

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-   This imaging method consists in turning back on the lattice to project each wave packet into a single well to turn them into a particle again. It is not a wave anymore. 

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-    The scientists say this image is just a simple demonstration. Their next step will be using it to study systems of strongly interacting atoms that are less well understood.  Studying such systems could improve our understanding of strange states of matter, such as those found in the core of extremely dense neutron stars, or the quark-gluon plasma that is believed to have existed shortly after the Big Bang. 

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May 20, 2024            ATOMS  -  have wave particle duality?              4474

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