IEEE Spectrum

Teleporting what matters [quantum computing]

Alexander Hellemans

Published Sep 1, 2004• 2 citations

Abstract

Physicists in Austria and the US have shown for the first time how to teleport the properties of one atom to another. At the National Institute of Standards and Technology, a team of teleporters trapped three beryllium ions. The ions - beryllium atoms with missing electrons and hence a positive charge - are subjected to forces from electric fields so that they can be held in an ion trap. Here, radio waves and electric fields from a set of electrodes hold the ions in a line but also allow them to be moved from one segment of the trap to the other. This way, ions could be brought over to the different laser beams used for entanglement and for the measurement of quantum states. Two atoms can be entangled by simultaneously undergoing changes in quantum state when hit with a specific series of laser pulses. The same teleportation protocol was used by another team at Innsbruck University. However, this team used a different type of trap, one with no segments. Instead of moving the ions to the lasers, the team was able to aim the lasers well enough so that they could move the laser beams to the ions. These simple trap systems have been found to be very promising and may first be applied in a specialized computer called quantum repeater. This kind of device, though still the stuff of mere theory, would extend the range of wiretap-proof quantum communication systems that encode messages in the polarization of photons.

DOI: 10.1109/mspec.2004.1330792

Related papers

Teleportation takes off

Quantum teleportation – the transmission and reconstruction of a quantum system over arbitrary distances – has been demonstrated for the first time by a group from the University of Innsbruck in Austria (Nature 1997 390 575). In addition to fundamental tests of quantum theory, the Innsbruck team says that teleportation will be a critical ingredient for quantum computation.

Physics WorldJan 1, 19981 citation

Teleportation Beams Up a Photon's State

A. Watson

Researchers at the University of Innsbruck in Austria have shown that part of the spin orientation of a photon of light can be transferred instantaneously to another photon, irrespective of distance. This work is being called the first experimental demonstration of quantum teleportation--the transfer of a quantum state from one particle to another, first proposed by IBM9s Charles Bennett and his collaborators in 1993. Quantum teleportation could have applications in quantum computing, say researchers, such as in constructing stable memories, protecting delicate quantum states, and communicating between quantum computers.

ScienceDec 12, 19972 citations

Trapped atoms and ions

Jonathan A. Jones, Dieter Jaksch

As discussed in Part I of this book, a qubit can in principle be encoded using two energy levels in an atom or ion. These levels are frequently referred to as | g ⧽ and | e ⧽, suggesting the ground state and some excited state, but the actual choice of levels is made so as to optimize the behavior of the system, and it is common to use two hyperfine sublevels of the ground state. As usual, we will simply call the levels |0⧽ and |1⧽. A quantum computer must, of course, have more than one qubit, and this is achieved by using more than one atom or ion, with one qubit encoded on each physical object. In order to make this approach practical, however, it is essential to trap the atoms or ions so that they can be held in a well-controlled environment where they can easily be manipulated. This can be achieved using electric and magnetic fields. The use of trapped ions was one of the first proposals for building quantum computers, and is still one of the best developed. Proposals involving trapped atoms are slightly more recent, and have both substantial advantages and disadvantages in comparison with trapped ions. These differences can ultimately be traced back to the fact that ions interact strongly with their environment and have long-range interactions with one another, while atoms interact more weakly and over shorter ranges. Comparing and contrasting the two approaches provides a useful general introduction to the problems underlying many other proposals. Ion traps It is relatively easy to trap an ion as it will interact strongly with an electric field through the Coulomb interaction.

Cambridge University Press eBooksJul 19, 20120 citations

Could trapping tiny ions crack the toughest codes?

JR Minkel

Computers that harness the weirdness of quantum mechanics could smash conventional encryption systems by factoring gigantic numbers fast-and factoring the product of two large prime numbers is the only way standard codes can be broken. The job would take conventional computers decades, not minutes. Encrypted data is still safe for the moment, because a powerful enough quantum computer is still many years away. But physicists have now demonstrated that quantum calculations can be done in a version of a quantum computer that could, in theory at least, be scaled up sufficiently. Rainer Blatt and his colleagues at the University of Innsbruck (Austria), in collaboration with Isaac Chuang of the Massachusetts Institute of Technology (MIT), have run a simple quantum algorithm in a computer that consists of only a single, very cold calcium ion. They employed a standard ion-trapping technique and a series of carefully tuned laser pulses to turn the ion into a computer that calculates using qubits-bits that can exist, seemingly paradoxically, as both a 1 and a 0 simultaneously. The Innsbruck-M IT team put this property of qubits to work in the Deutsch-Jozsa algorithm.

IEEE SpectrumMar 1, 20030 citations

Quantum State Tomography

George Rajna

Quantum state tomography is the process of reconstructing – or more precisely completely characterizing – the quantum state of an object as it is emitted by its source, before a possible measurement or interaction with the environment takes place. [25] A team of researchers led by LMU physics professor Immanuel Bloch has experimentally realized an exotic quantum system which is robust to mixing by periodic forces. [24] A group of scientists led by Johannes Fink from the Institute of Science and Technology Austria (IST Austria) reported the first experimental observation of a first-order phase transition in a dissipative quantum system. [23] ORNL researchers have discovered a new type of quantum critical point, a new way in which materials change from one state of matter to another. [22] New research conducted at the University of Chicago has confirmed a decades-old theory describing the dynamics of continuous phase transitions. [21] No matter whether it is acoustic waves, quantum matter waves or optical waves of a laser—all kinds of waves can be in different states of oscillation, corresponding to different frequencies. Calculating these frequencies is part of the tools of the trade in theoretical physics. Recently, however, a special class of systems has caught the attention of the scientific community, forcing physicists to abandon well-established rules. [20] Until quite recently, creating a hologram of a single photon was believed to be impossible due to fundamental laws of physics. However, scientists at the Faculty of Physics, University of Warsaw, have successfully applied concepts of classical holography to the world of quantum phenomena. A new measurement technique has enabled them to register the first-ever hologram of a single light particle, thereby shedding new light on the foundations of quantum mechanics. [19] A combined team of researchers from Columbia University in the U.S. and the University of Warsaw in Poland has found that there appear to be flaws in traditional theory that describe how photodissociation works. [18] Ultra-peripheral collisions of lead nuclei at the LHC accelerator can lead to elastic collisions of photons with photons. [17]

Feb 1, 20176 citations

An Investigation on Quantum Teleportation

Shefali Singhal, Anjali Jain, Anil Kumar Gankotiya +1 more

Teleportation also called, as Quantum Teleportation is a technique, which involves the duplication or re-creation of physical properties using light beams. Teleportation involves the transfer of States between two separate atoms. It relies on a strange behaviour that exists at the atomic scale known as entanglement, whereby two particles can have related properties even when they are far apart. Entanglement allows particles to have a much closer relationship than is possible in classical physics. If two particles are entangled, we can know the state of one particle by measuring the state of the other. For example, two particles can be entangled such that the spin of one particle is always up when the spin of the other is down, and vice versa. An additional feature of quantum mechanics is that the particle can exist in a superposition of both these states at the same time. The landmark experiments are being viewed as a major advance in the quest to achieve ultra-fast computers, inside which teleportation could provide a form of invisible wiring. These machines would be able to handle far bigger and more complex loads than today's super-computers, and at many times their speed. Here in this report, we are going to discuss about the technique involved in quantum computing, quantum cryptography and quantum teleportation and in specific Quantum Computers along with its advantages and disadvantages. Moreover, the future aspects of quantum teleportation such as human teleportation have also been overviewed.

Jan 1, 20124 citations