| 06.18.2002 | Quantum teleportation technique improved. |
| 02.07.2002 | Teleportation gets closer to reality. |
| 01.17.2002 | Breakthrough towards understanding gravity. |
An Australian team led by Ping Koy Lam at the Australian National University in Canberra stated to have significantly improved a technique for teleporting a laser beam across a distance of a few metres in a laboratory using quantum entanglement.
Researchers at the California Institute of Technology, Aarhus University in Denmark and the University of Wales in Bangor first demonstrated the teleportation of a laser beam consisting of millions of photons in 1998. It seems this process has now been made far more robust and reliable, although other scientists say the improvement is not precisely indicated by the team.
The popular press was enthusiastic in presenting the news in due Star Trek context, but it does not justify being called the first really big breakthrough. The team has improved the technique of similar experiment done in 1998 (see underneath for other recent achievements), using well established quantum physics.
Quantum teleportation is a reality and is improved constantly, however, most researchers agree that teleporting large and complex objects seems to remain a very distant dream.
Teleportation may have been beamed one step closer to reality after Indian physicists suggested a theory that could be used to make two particles behave as one, no matter how far apart they are.
Reported this week in New Scientist, Sougato Bose and Dipankar Home, of the Bose Institute in Calcutta, announced a breakthrough in a method that could be used to 'entangle' particles, or what Einstein once described with some reluctance as a "spooky action at a distance."
Quantum entanglement allows two atoms to behave as one, and could theoretically be used to teleport objects by transferring the properties of one atom to another.
A beam splitter is used to send two identical electrons down either of two paths, with an equal probability that the electrons will go down both paths or the same path.
Bose and Home have shown that if one electron is detected on each path, they become entangled. "One of the advances we have made is that these two particles could be from completely independent sources," Bose was quoted as saying.
Bose and Home reckon the technique could be applied to any object, atoms, molecules, and maybe something bigger.
Last year Danish boffins at the University of Aarhus made a breakthrough on a similar level, when Eugene Polzik and his colleagues made two samples of several trillion atoms interact at a distance.
Researchers have measured the quantum effects of gravity for the first time, a significant breakthrough in the understanding of an enigmatic force at tiny scales.
The work is reported in the January 17 issue of the journal "Nature."
Gravity's effects is relatively easy to observe in the everyday world but physicists are not sure where gravity actually comes from. And on very small scales, the sizes of subatomic particles, the effect of gravity is so weak that they have never been seen at work.
Theory says gravity should be at work there, nonetheless. And seeing it at work at these scales allows a inprovement in our understanding of the nature of gravity.
Observing phenomena and taking measures at this scale is both captial and challengin because it is the scale where quantum effects fully set rules that are not generally perceptible in the everyday world. For example, if one precisely tracks an electron's speed, then it does not have a position anymore, not because of imprecise apparatus but because this is how it really is. Likewise if one knows our electron's position precisely at a certain time, there is no way to tall where it is going. Also, quantum behaviour of matter and energy makes every thing jump from one state to another rather than move from one state to another. Such rule applies to all matter under the influence of what we interpret as nature's four fundamental forces: electromagnetism, the strong and the weak nuclear forces, and gravity.
Gravity is particularly hard to investigate at subatomic level, because its strength is largely overwhelmed be the other forces. Up to now, it was not clear how gravity could "fit in" quantum mechanics. So the researchers, led by Valery Nesvizhevsky at the Laue-Langevin Institute in Grenoble, France, isolated hundreds of neutrons from all major effects except gravity, then watched them in a special detector as gravity pulled them down.
It was not a smooth fall. As expected, the neutrons fell in quantum jumps.
Thomas Bowles of the Los Alamos National Laboratory in an accompanying analysis of the article in Nature, stated: "The work of Nesvizhevsky and colleagues could provide physicists with a new probe of the fundamental properties of matter."
He said the new observational technique might allow scientists to figure out why quantum mechanics is at odds with Einstein's theory of general relativity, which describes how gravity treats large objects in the universe.
He also stated: "It might even solve a most elusive goal in helping researchers understand out what actually creates gravity."
I cannot resist, I must add: "when we understand what actually creates gravity, then we can start to explore gravity control."
