Outline of the Talk Introduction Need for Teleportation The Beginning.. Failures and further Advancements How feasible is Teleportation .?? Remarkable Achievements Application in Real World Advantages of QT References
What Teleportation is..??Quantum teleportation, or entanglement-assistedteleportation, is a process by which a qubit (the basicunit of quantum information) can be transmitted exactlyfrom one location to another, without the qubit beingtransmitted through the intervening space. It includesmaking an object disintegrate in one place while aperfect replica appears somewhere else.
Need for TeleportationVarious forms of transportation require us to cross a physicaldistance, which can take anywhere from minutes to many hours. Telecommunication + Transportation = Teleportation
How does all these start.?? In 1993, the idea of teleportation moved out of the realm ofscience fiction and into the world of theoretical possibility. The ideawas first expounded by Charles Bennett and his co-workers fromIBM. They confirmed that quantum teleportation was possible, but onlyif the original object being teleported was destroyed. The procedure for teleportation in science fiction varies fromstory to story but generally goes as follows: A device scans the original object to extract all the informationneeded to describe it. A transmitter sends the information to the receiving station toobtain an exact replica of the original.
It violated the Heisenberg’s Uncertainty Principle, according towhich one can’t perform a perfect scan of the object to be teleported.Because the more accurately an object is scanned, the more it isdisturbed by the scanning process, until one reaches a point where theobject’s original state has been completely disturbed, still without havingextracted enough information to make a perfect exact replica. The location or velocity of every atom and electron would be subjectedto errors. The law makes it impossible to measure the exact quantum state ofany object with certainty. Therefore, it would seem that a perfect copy cannot be made.
But if you can’t know the position of particle, then how can youteleport it? OrIf one can’t extract enough information from an object to make aperfect replica, it would seen that a perfect copy can’t be made.In 1998, physicists at the California Institute of Technology(CalTech), along with two European groups, turned the IBM ideasinto reality by successfully teleporting a photon, a particle ofenergy that carries light, using a phenomenon known asENTANGLEMENT or EINSTEIN-PODOLSKY-ROSEN (EPR)EFFECT.
Entanglement Or EPR EffectThe existence of an “entangled state” was suggested in an experiment bythe 3 scientists in 1935.It states that when two particles come into contact with one another,they can become “entangled".In an entangled state, both particles remain part of the same quantumsystem so that whatever you do to one of them affects the other one in apredictable way. Thus, it shows how, in principle, entangled particles mightserve as "transporters" of sort.
ENTANGLED PHOTON PAIRS are created when a laser beam passes through acrystal such as beta barium borate. It converts a single photon into two photonsof lower energy, one polarized vertically (on red cone), one polarized horizontally(on blue cone). If the photons happen to travel along the cone intersections(green), neither photon has a definite polarization, but their relative polarizationsare complementary i.e. they are then entangled.
The process behind EntanglementIn entanglement, at least 3 photons are needed to achieve quantumteleportationPhoton A: The photon to be teleportedPhoton B: The transporting photonPhoton C: The photon that is entangled with photon B If researchers tried to look too closely at photon A withoutentanglement, they would bump it, and thereby change it. By entangling photonB and C, researchers can extract some information about photon A, and theremaining information would be passed on to B by way of entanglement, andthen on to photon C. When researchers apply the information from photon A tophoton C, they can create an exact replica of photon A. However, photon A nolonger exists as it did before the information was sent to photon C.
How hard is it to teleport an atom? Photons have very few pairs of parameters: color, duration,amplitude, phase, polarization, beam size. That’s about it. While atoms have a lot more (about 100 different pairs). Recent discoveries have led to the teleportation of photons. So, with further development intechnology, it wouldn’t be tough enoughto teleport the atom in near future.
How hard is it to teleport a living being? To date there are a few science experiments that hascreated life. The smallest living organism are viroid. Some areas small as 10,000 atoms. We have teleported only one pair ofinformation. Teleporting a viroid is 100*10,000times (106 times)harder=roughly a milliontimes harder.
How hard is it to teleport a human? There is about 1027 atoms in a person. With 100 parameter pairs per atom, that’s about 1029 pair ofinformation. So far we have done only 1 pair, so a human isabout 1029 times harder. For a person to be transported, amachine would have to be built that canpinpoint and analyse all of the 1027atoms that make up the human body.
In 2002, some researchers at the Australian NationalUniversity successfully teleported a laser beam. In 2004, researchers from the University of Vienna andthe Austrian Academy of Science teleported particles of lightover a distance of 600m using Optical Fibre. In Oct 4,2006, at the Neil Bohr’s Institute, Denmark, Dr.Polzik and his team teleported information stored in a laserbeam into a cloud of atom across 1.6 feet. It involvesteleportation between light and matter, two different objects.
And they continued.. In May 2010, a team of 15 Chinese researchers from TsinghuaUniversity in Beijing and the Hefei National Laboratory achievedsecure quantum-key distribution over 16 kilometres of free-space. In April 2011, physicist at University of Tokyo, teleported acomplex set of quantum information from one point to another. In May 2012, an international research team including severalscientists from the University of Waterloo has achieved quantumteleportation over a record-breaking distance of 143 kilometresthrough free-space between the two Canary Islands of La Palmaand Tenerife off the Atlantic coast of North Africa.
Quantum Cryptography Quantum cryptography allows the transmission of information with100% security ensured by the law of physics. Potential application for commerce and military purpose.Quantum Computation Moore’s law predicts that computer double its speed, memoryperformance, etc. every 18 months. But the size and weight of computersremain the same. This means more and more is expected from fewer and fewer atoms.Eventually, classical physics will no longer valid. A new way of computingwill be required.
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Transmission at higher rates. Secure data transmission. Can detect eavesdropping. Transportation becomes much easier. Reduced cost of transportation.Advantages Accidents will be completely absent. Faster transportation.
References http://www.research.ibm.com http://www.electronicsnews.com.au http://en.wikipedia.org http://www.youtube.com http://www.wired.com Entanglement and Quantum Teleportation by Stephen Bartlett