Researchers have the bosenova blues A technique that brings the quantum world up to everyday sizeshas physicists scratching their heads.
Jeremy Thomson http://www.nature.com/news/2001/010319/full/news010322-3.html [image: lbert Einstein postulated the existence of BECs in 1924]lbert Einstein postulated the existence of BECs in 1924 Some clusters of very cold atoms have physicists foxed, the American Physical Society's March meeting heard this week in Seattle. Bose-Einstein condensates, the bizarre form of matter that bridges the tiny, topsy-turvy world of quantum mechanics and the everyday world, are pulling dramatic tricks with which today's theories just can't cope. Ordinary matter comes in five forms. Three -- solids, liquids and gases -- are familiar. The fourth, plasmas, are found in high-temperature systems such as flames and fluorescent tubes. You could be forgiven for having never heard of the fifth: the Bose-Einstein condensate (BEC). Christened in honour of Albert Einstein, who postulated their existence in 1924 based on the work of Satyendra Bose, the first BECs were produced by Eric Cornell and Carl Wieman at the University of Colorado in 1995. These curious entities never occur naturally, can exist only at temperatures a few ten-billionths of a degree above absolute zero (-273 degrees Celsius) and until recently could contain only a few hundred atoms. Even so, they fascinate physicists keen to deepen their understanding of quantum phenomena. As an atom cools, it moves increasingly slowly, causing its wavefunction (roughly speaking, the area in which it might be found) to grow. Eventually, the wavefunctions from neighbouring atoms overlap and the whole condensate starts to behave as a single quantum-mechanical object. It is hard to form a stable BEC of more than 100 atoms, and seeing what's going on in condensates so small is very difficult. The recent discovery of a particular mode in rubidium-85 called a 'Feshbach resonance' increased the maximum condensate size to several tens of thousands of atoms -- but only at just two billionths of a degree above absolute zero. "Damn cold by anyone's standards," as Wieman says. Nonetheless, the new technique gave researchers a tool rather like a pair of magnetic pliers to manipulate the condensates. Their results have them scratching their heads. When compressed quickly enough, a condensate explodes, blasting off the outer atoms and leaving a cold, collapsed remnant. The effect has been dubbed a 'bosenova' because of its similarity to a supernova (an exploding star). Unsurprisingly, the size of the remnant left when the condensate does a bosenova depends on the energy of the explosion. But, strangely, the number of atoms blasted off does not change. This is a real surprise, particularly as researchers currently have no idea what happens to the remaining atoms. Unexplained jets have also been observed projecting from the mass of atoms just before it collapses. And the more egg-shaped the initial condensate (physicists call this anisotropic), the rounder the remnant -- entirely contrary to expectations. Charles W. Clark of the National Institute of Standards and Technology in Boulder, Colorado, has even observed curious smoke-ring formations within a BEC1 <http://www.nature.com/news/2001/010319/full/news010322-3.html#B1>. "These are not complicated crystals with many degrees of freedom and complex interactions we are talking about; they are just atoms. We understand atoms, right?" Wieman jokes. "Basic physics is missing to explain these effects." - References 1. Anderson, B. P., Haljan, P. C., Regal, C. A., Feder, D. L., Collins, L. A., Clark, C. W. & Cornell, E. A. Watching dark solitons decay into vortex rings in a Bose-Einstein condensate. *Physics Review Letters* (in press). On Tue, Jun 13, 2017 at 1:10 PM, Kevin O'Malley <kevmol...@gmail.com> wrote: > I like where this is headed, especially when looking at it in a 1 > dimensional viewpoint. > The bosenova 'explosion' has been witnessed but no one really knows what > caused it nor where the energy came from to drive all that matter away. > Seems like 1 or 2 fusion events might be enough energy to do it. > > > Atoms don't dance the 'Bose Nova'September 3, 2009 > [image: Atoms don't dance the 'Bose Nova'] > <https://3c1703fe8d.site.internapcdn.net/newman/gfx/news/hires/2009/tubes.jpg> > With two laser beams the researchers generate an optical lattice, where > the atoms are confined to vertical one-dimensional structures (red) with up > to 15 atoms aligned in each tube. > > (PhysOrg.com) -- Hanns-Christoph Naegerl's research group at the Institute > for Experimental Physics, Austria, has investigated how ultracold quantum > gases behave in lower spatial dimensions. They successfully realized an > exotic state, where, due to the laws of quantum mechanics, atoms align > along a one-dimensional structure. A stable many-body phase with new > quantum mechanical states is thereby produced even though the atoms are > usually strongly attracted which would cause the system to collapse. The > scientists report on their findings in the leading scientific journal > *Science*. > > Interactions are considerably more drastic in low-dimensional systems than > in three-dimensional ones. Thus, physicists take a special interest in > these systems. In physics zero-dimensional quantum dots > <https://phys.org/tags/quantum+dots/>, two-dimensional quantum wells and > also one-dimensional quantum wires are known. The latter are spatial > potential structures, where carriers can move only one-dimensionally. > > Whereas quantum dots and wells can be realized and analyzed relatively > easily, it is much harder to investigate quantum wires in solid-state > bodies. Hanns-Christoph Naegerl’s research group of the Institute for > Experimental Physics of the University of Innsbruck has now tried something > totally different: In a cloud of ultracold atoms they realized > one-dimensional structures and thoroughly analyzed their properties. > > *Surprising observation* > > In a vacuum chamber <https://phys.org/tags/vacuum+chamber/> the > physicists produced a Bose-Einstein condensate > <https://phys.org/tags/bose+einstein+condensate/> with approx. 40,000 > ultracold cesium atoms. With two laser beams they generated an optical > lattice, where the atoms were confined to vertical one-dimensional > structures with up to 15 atoms aligned in each tube. The laser beams > prevent the atoms from breaking ranks or changing place with each other. > [image: Atoms don't dance the 'Bose Nova'] > <https://3c1703fe8d.site.internapcdn.net/newman/gfx/news/hires/2009/tubes_infinite_length.jpg> > A stable many-body phase with new quantum mechanical states is produced > (front) even though the atoms are usually strongly attracted which would > cause the system to collapse (back). > > Using a magnetic field, the scientists could tune the interaction between > the atoms: “By increasing the interaction energy between the atoms > (attraction interaction), the atoms start coming together and the structure > quickly decays,“ Naegerl explains what is called among experts the > "Bosenova" effect. > > "By minimizing the interaction energy, the atoms repel each other > (repulsive interaction), align vertically and regularly along a > one-dimensional structure and the system is stable." If the interactions > are switched from strongly repulsive to strongly attractive, a surprising > effect can be observed. "We thereby achieve an exotic, gas-like phase, > where the atoms are excited and correlated but do not come together and a > 'Bosenova' effect is absent," Naegerl says. The phase was diagnosed by > compressing the quantum gas and measuring its stiffness. "However, this > excited many-body phase can only be realized by a detour via repulsive > interaction. This phase was predicted four years ago and we have now been > able to realize it experimentally for the first time," Elmar Haller says. > He is first author of the research paper, which is now published in the > renowned scientific journal *Science*. Currently, research on > low-dimensional structures receives a lot of attention internationally and > it may help to better understand the functioning of high-temperature > superconductors. > > *Cold atoms as an ideal field of experimentation* > > "Ultracold quantum gases offer a big advantage: They can be isolated > against the environment quite well," Naegerl explains. "Moreover, in our > experiment we can practically rule out defects we often find in solid-state > bodies." With this successful experiment the Innsbruck quantum physicists > found an ideal experimental setup to further study the properties of > quantum wires. Naegerl’s team of scientists clearly benefits from the long > standing and successful research on ultracold atoms and molecules by > another Innsbruck group of physicists: the research group led by > Wittgenstein laureate Prof. Rudolf Grimm, which has already assumed a > leading role internationally. > > In addition to producing the first Bose-Einstein condensates using cesium > atoms and molecules, the scientists also observed exotic states such as the > Efimov-state and repulsive quantum pairs experimentally for the first time > worldwide. "The research work of Hanns-Christoph Naegerl and his team once > more underlines the international significance of our research projects," > Rudolf Grimm says. > > The experimental physicists of the research project on quantum wires also > benefited from a very close cooperation with the theoretical physicists of > the quantum physics stronghold in Innsbruck. The project of START-awardee > Hanns-Christoph Naegerl is funded by the Austrian Science Funds and the > European Union. > > *More information:* Realization of an Excited, Strongly-Correlated > Quantum Gas Phase. Haller E, Gustavsson M, Mark MJ, Danzl JG, Hart R, > Pupillo G, Nägerl HC. *Science *4. September 2009 ( > DOI:10.1126/science.1175850 <http://dx.doi.org/10.1126/science.1175850>) > > Provided by University of Innsbruck > > On Tue, Jun 13, 2017 at 11:22 AM, bobcook39...@hotmail.com < > bobcook39...@hotmail.com> wrote: > >> Kevin— >> >> >> >> Thanks for that instructive review. >> >> >> >> It seems that Storms was worried about a fast reaction of the BEC’s. >> >> >> >> Ball lightening or Bosenovas may in fact be a reaction close to what >> Storms was worried about in the thread of 2013 you have found. The >> following link addresses the possibility of bosenovas. >> >> >> >> https://www.nist.gov/news-events/news/2001/03/implosion-and- >> explosion-bose-einstein-condensate-bosenova >> >> >> >> Various LENR researchers have witnessed what they report as bosenovas. >> >> >> >> Bob Cook >> > >
