Giant Rydberg atoms confined in a micro-glass cell

Jan 14, 2010

Rydberg atoms are highly sensitive atoms, as one electron is only loosely bound. Compared to 'normal' atoms which are one tenth of a nanometer in size those giant atoms are ~100 nanometers large. Due to their sensitivity they are very useful for quantum logic operations.

As they can feel each other over distances up to several micrometers they can be used as conditional switches for quantum states, for example to connect nodes of a . The miniaturisation of such quantum devices will seemingly also be hindered by this large sensitivity as were expected to also interact strongly with confining walls.

Now researchers of the 5. Physikalisches Institut at the Universität Stuttgart, Germany, showed contrary to that expectation that it is possible to confine giant Rydberg atoms in microscopic glass cells und circumstances without significant disturbance. For this micron sized glass cells fabricated by them were filled with 'normal' hot atoms in the vapor phase. Then they were converted into Rydberg atoms by laser excitation.

They report on the progress in a recent publication in Nature Photonics.  It seems that hot Rydberg atoms confined in micro-glasscells have become hot candidates for miniaturized quantum devices at or even above room temperature.

Researchers from the 5. Physikalisches Institut are working with those giant atoms for several years now. Up to now their research concentrated on ultracold atoms. Using elaborate cooling techniques in big UHV chambers the atoms could be isolated from the environment. They have investigated the interaction between Rydberg atoms and have observed a novel molecular bond based on Rydberg recently. The apparatus for those experiments is however quite complex and certainly not well suited for applications. Therefore they were looking for an easy to handle alternative which are scalable and suited for massively parallel production.

Microstruturing of glass is well established technique and is applied also in flat-panel display technology. In order to use this technology for the confinement of atoms, it was necessary to investigate the interaction of Rydberg atoms with nearby glass walls. If the sensitive Rydberg atoms would be disturbed by the wall, then application like quantum information processing would become impossible. Now the group succeeded to investigate the interaction of Rydberg atoms with glass walls. The confined them between two glass walls separated by less than 1 micrometer and detected the energy shifts using a coherent spectroscopy technique which is very sensitive to loss of quantum information (decoherence). They found, that different Rydberg states interact with the wall with different strengths and found a specific state which was almost not affected by the wall. Therefore it now seems feasible to apply Rydbergatoms in microcells for purposes.

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More information: Harald Kübler, James P. Shaffer, Thomas Baluktsian, Robert Löw, Tilman Pfau: Coherent excitation of Rydberg atoms in micrometre-sized atomic vapour cells, Preprint: arXiv.org/abs/0908.0275 .

Provided by University of Stuttgart

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flaredone
not rated yet Jan 14, 2010
Ball lightning is supposedly formed by dense clouds of Rydberg atoms, stabilized by London cohesion interactions. It gives orange to red color to ball lightning and high density of microwave energy.

http://www.unexpl...ing4.jpg

http://citebase.e.../0302063
Parsec
not rated yet Jan 14, 2010
Thanks for the reference flaredone. I did note that this is only a proposed mechanism, but the arguments and calculations are quite convincing to me.

I am unclear on the applicability of this to the article however. I would also note that the editing is terrible. Even so, its very interesting and I gave it a 5.
Lolipop
not rated yet Jan 15, 2010
Sound like we soon (in ten years) may have a quantum computer that outperforms regular computers.
flaredone
not rated yet Jan 15, 2010
I did note that this is only a proposed mechanism
I presume, more complex phenomena including supersymmetric gravitophotons could be involved here (a product of photon and graviton coupling, responsible for Casimir force). The ball lightning is sort of strangelet, the size of which is comparable to human scale (size of solitons in human brain), CMB wavelength and size of black hole, whose lifespan correspond the age of observable Universe. We are facing anthropocentric finely tuned scale here.
flaredone
not rated yet Jan 15, 2010
Sound like we soon (in ten years) may have a quantum computer that outperforms regular computers.
This is not so simple. For example, human brain is quantum-like computer, optimized for heavily parallelized tasks like 3D navigation and image recognition. But its scalar power as expressed in GFLOPs or even MIPS is nothing exceptional with compare to hand held calculator. Even the byte flow if information in optical nerve is comparable to byte flow in bus of modern computers (40 Gbytes/sec).

Just because the stability of sequential computers is limited by quantum phenomena in the same way, like at the case of quantum computers, I don't think, introduction of quantum computers could increase power of sequential computing significantly, because its limited by quantum uncertainty in both cases. We could achieve the similar result by massive parallelization of von-Neumann computers.
flaredone
not rated yet Jan 15, 2010
Recently I read about simulation of half or rat brain by supercomputer. In context of energy consumption such attempt is still terribly inefficient. But with respect to total volume occupied by microprocessor circuits the informational density wouldn't be so different from mouse brain density. Contemporary microprocessors are surprisingly compact in comparison to biological brains, they're just inefficient with respect to their energy consumption.

http://news.bbc.c...0965.stm
Lolipop
not rated yet Jan 17, 2010
This is not so simple. For example, human brain is quantum-like computer, optimized for heavily parallelized tasks like 3D navigation and image recognition. But its scalar power as expressed in GFLOPs or even MIPS is nothing exceptional with compare to hand held calculator. Even the byte flow if information in optical nerve is comparable to byte flow in bus of modern computers (40 Gbytes/sec).

Just because the stability of sequential computers is limited by quantum phenomena in the same way, like at the case of quantum computers, I don't think, introduction of quantum computers could increase power of sequential computing significantly, because its limited by quantum uncertainty in both cases. We could achieve the similar result by massive parallelization of von-Neumann computers.


Of course I meant outperforming regular computers in those "quantum-parallelized" tasks - where there are alot of outcomes.
antialias
not rated yet Jan 18, 2010
Sound like we soon (in ten years) may have a quantum computer that outperforms regular computers.


More like a mix of both. There are tasks at which quantum computers are pretty bad compared to regular computers and vice versa. E.g. for sequential operations quantum computers give no benefit (and possibly even some drawbacks due to the probability of error during readout)

Their advantages come into play with parallel processing, searches, factoring and the like
Lolipop
Feb 01, 2010
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