teleportasi

Beam me up Scotty! Itulah kalimat khas Kapten Kirk ketika ingin kembali kekapal Enterprise dalam film Star Trek. Impian untuk bisa berpindah tempat dalam sesaat seperti mereka memang masih menjadi fiksi ilmiah, tetapi sebuah tim ilmuwan Denmark berhasil membuat terobosan dalam memindahkan informasi dari cahaya menjadi materi.
Adalah Professor Eugene Polzik dan timnya dari Institute Niels Bohr, terletak di Universitas Copenhagen Denmark, yang berhasil melakukan terobosan itu. Polzak dan timnya berhasil memindahkan informasi sebuah obyek makroskopik(terdiri dari atom yang sangat banyak) sejauh setengah meter. Mereka percaya jarak perpindahan tersebut akan bisa ditambah untuk kedepannya.
“Perpindahan antara 2 atom tunggal telah berhasil dilakukan 2 tahun lalu namun itu hanya dalam jarak beberapa millimeter.” Komentar Polzik. “ Metode kami memungkinkan terleportasi dengan jarak yang lebih jauh lagi karena melibatkan cahaya sebagai pembawa.” Tambahnya lagi.
Terobosan ini bukan berarti kita akan mulai berpindah tempat dengan cahaya dalam beberapa tahun kedepan. Yang pasti terobosan ini menandai sebuah perkembangan dalam bidang informasi kuantum dan komputer, memungkinkan perpindahan dan pemrosesan informasi dengan cara yang sebelumnya tampak mustahil.
Sumber : http://www.g2glive.com/?m=news.detail&id=1720
Bagaimana Teleportasi
Tim ilmuwan dari Institut für Experimentalphysik di Innsbruck, Austria dan National Institute of Standards and Technology (NIST) di Boulder, Colorado, secar terpisah berhasil melakukan teleportasi ion-ion dari unsur kalsium dan beryllium. Ini untuk kali pertama para ilmuwan dapat meniru teknologi Star Trek meski baru memindahkan ion sub atomik. Intinya, teleportasi ini adalah teleportasi kuantum.

1. Sepasang ion, B dan C, yang terlibat diciptakan bersamaan.
2. Keadaan yang ingin diteleportasikan diciptakan di dalam sebuah ion, sebut saja A.
3. Salah satu ion yang berpasangan, B dilibatkan dengan A. Keadaan internal keduanya lalu diukur.
4. Keadaan kuantum dari ion A dikirimkan ke ion C dan mentransformasikan ion C (sekaligus menghancurkan keadaan kuantum asli dari ion A).
5. Keadaan yang diciptakan untuk ion A telah diteleportasikan kepada ion C.

Teleportasi ini berlangsung dalam hitungan milidetik dan pada saat penekanan tombol.

Quantum
The phenomenon of quantum teleportation was quickly changing from being an exotic by-product of quantum theory to becoming a practical application in computing and information transfer. Teleportation concerns the instantaneous transfer of information from one place to another. It circumvents the restriction on exceeding the speed of light (a restriction imposed by relativity theory) by making use of the phenomenon called entanglement. If two quantum systems are prepared together, so that their states are “entangled,” then separated to an arbitrarily large distance, measurement of the state of one system will instantaneously define the state of the second system. The state is said to represent a qubit, or quantum bit, of information.
Two scientific teams using different systems achieved teleportation of the quantum states of ions (electrically charged atoms). Previous experiments had demonstrated teleportation only with the quantum states of beams of light. The ion-teleportation experiments consisted essentially of preparing the initial quantum state of one particle and then teleporting that state to a second particle at the push of a button. Mark Riebe and co-workers at the Institute for Experimental Physics, University of Innsbruck, used three calcium ions trapped together at an ultrahigh vacuum. One ion constituted the source, and the second served essentially as carrier of information to the third, the receiver. Murray Barrett and his colleagues at the National Institute of Standards and Technology, Boulder, Colo., produced similar results with beryllium ions, using a different form of trap and experimental layout. Although there are many types of particles that might function as the basis of practical devices for storing and transporting qubits, including photons and atoms, trapped ions, or quantum dots, tiny isolated clumps of semiconductor atoms with nanometer dimensions, it was generally agreed that the ion-trap setup used in these experiments was one of the most promising candidates.
Meanwhile, advances continued to be made in experiments on teleportation of light. Rupert Ursin and co-workers at the Institute for Experimental Physics, University of Vienna, described teleportation of photons over a distance of 600 m (about 2,000 ft) and Zhao Zhi and co-workers at the University of Science and Technology of China demonstrated five-photon entangled states, an important step on the road to the development of quantum communication. Other experimenters were considering the transfer of quantum information via the interaction of matter and light. Physicist Boris Blinov and colleagues in the department of physics at the University of Michigan succeeded in observing entanglement between a trapped ion and an optical photon.

On the other hand, Irinel Chiorescu and colleagues at Delft (Neth.) University of Technology coupled a two-state system—made up of three in-line Josephson junctions—to a superconducting quantum interference device (SQUID) on the same semiconductor segment. The SQUID served as a detector for the quantum states, and entangled states could be generated and controlled. The experiment pointed the way to the possible use of solid-state quantum devices for controlling and manipulating quantum information. Such experiments were made possible by advances in a number of fields, from precision laser spectroscopy to techniques involving ultralow temperature and ultrahigh vacuum. In the midst of this experimental ferment, it was not yet clear which path might eventually lead to the building of large-scale quantum computers, overcoming the inherent restrictions of electronic devices.

Experimental techniques in microscopy reached a level of sophistication that made it possible to study the spin of a single electron a short distance below the surface of a solid. Dan Rugar and co-workers at the IBM Almaden Research Center, San Jose, Calif., combined the techniques of magnetic resonance imaging and atomic force microscopy to create a technique called magnetic resonance force microscopy (MRFM). They mounted a micromagnetic probe on a tiny cantilever a short distance above the surface of the material being studied. The probe generated a magnetic-field gradient so large that the interaction between the probe’s magnetic field and that of a single electron produced a measurable mechanical force on the probe. The new technique not only dramatically increased the resolution of magnetic resonance imaging but also held promise for helping make use of atomic spin for qubits in information storage.

Anton Zeilinger and co-workers at the Institute for Experimental Phases of the University of Vienna carried out an experiment concerning the transition between the quantum and classical realms of physics. It demonstrated the fallacy of the common tendency to separate qualitatively the quantum behaviour of extremely small particles, such as electrons, from the classical behaviour of everyday objects, such as billiard balls. Using relatively large cagelike carbon C₇₀ molecules, Zeilinger’s group observed a smooth transition between quantum and classical behaviour. They heated the molecules and sent them through a series of gratings onto a detector, in a rerun of the seminal two-slit experiment that showed the quantum nature of fundamental particles such as electrons. At low temperatures the molecules formed an interference pattern at the detector—a manifestation of quantum behaviour. As the temperature of the molecules was increased, however, there was a swift but smooth transition to behaviour like that of classical objects.

This experiment demonstrated that the division between the quantum and classical realms is not a function of the size of the particle but most likely a function of the interaction of the particle with the outside world (in this case the emission of radiation by the heated molecules).
David G.C. Jones