http://phys.org/physics-news/quantum-physics/ en-us PhysOrg Team Phys.Org provides the latest news on quantum physics, wave particle duality, quantum theory, quantum mechanics, quantum entanglement, quantum teleportation, and quantum computing. (Phys.org) -- Quantum computers are still years away, but a trio of theorists has already figured out at least one talent they may have. According to the theorists, including one from the National Institute of Standards and Technology (NIST), physicists might one day use quantum computers to study the inner workings of the universe in ways that are far beyond the reach of even the most powerful conventional supercomputers. http://phys.org/news257758899.html Physics - Quantum Physics 2012-06-01T08:41:50-07:00 (Phys.org) -- A European team of physicists has bested the record set by a team of Chinese researchers last month for distance in teleporting quantum bits (qubits). Where the Chinese team accomplished their feat by teleporting photons across a lake, the European team did so by performing the same feat across the ocean between two islands off the coast of Africa. It was apparently no easy feat as the team describes in the paper they’ve written and uploaded to the preprint server arXiv; they had so much foul weather to contend with that their experiment took nearly a year to complete. The record breaking distance by the Chinese team was close to 100 kilometers. The Europeans bested that mark by almost fifty kilometers, setting up a possible rivalry between the two teams to see which might be the first to successfully teleport a qubit to an orbiting satellite. http://phys.org/news257758516.html Physics - Quantum Physics 2012-06-01T08:35:33-07:00 (Phys.org) -- One of the main sticking points to creating a true quantum computer capable of performing meaningful work, is the problem of storing quantum state information in memory. Recent efforts have resulted in highly efficient memory that lasted only a short time or low efficient memory that lasts longer. Now, a combined group of two teams, one from China and one from Germany, have come up with a way that appears to offer the best of both worlds. As they describe in their paper published in the journal Nature Physics, they found that they were able to store quantum information in atomic spin waves. http://phys.org/news257589516.html Physics - Quantum Physics 2012-05-30T09:38:46-07:00 European researchers have made important advances in understanding the major stumbling block to realisation of quantum computers, a phenomenon known as decoherence. http://phys.org/news257588448.html Physics - Quantum Physics 2012-05-30T09:20:55-07:00 The storage of light-encoded messages on film and compact disks and as holograms is ubiquitous---grocery scanners, Netflix disks, credit-card images are just a few examples. And now light signals can be stored as patterns in a room-temperature vapor of atoms. Scientists at the Joint Quantum Institute have stored not one but two letters of the alphabet in a tiny cell filled with rubidium (Rb) atoms which are tailored to absorb and later re-emit messages on demand. This is the first time two images have simultaneously been reliably stored in a non-solid medium and then played back. http://phys.org/news257521254.html Physics - Quantum Physics 2012-05-29T14:42:03-07:00 (Phys.org) -- Quantum computers may someday revolutionize the information world. But in order for quantum computers at distant locations to communicate with one another, they have to be linked together in a network. While several building blocks for a quantum computer have already been successfully tested in the laboratory, a network requires one additonal component: a reliable interface between computers and information channels. In the current issue of the journal Nature, physicists at the University of Innsbruck report the construction of an efficient and tunable interface for quantum networks. http://phys.org/news256995150.html Physics - Quantum Physics 2012-05-23T13:00:11-07:00 (Phys.org) -- In quantum physics physical processes in condensed matter and other many-body systems can often be described with quasiparticles. In Innsbruck, for the first time Rudolf Grimm’s team of physicists has succeeded in experimentally realizing a new quasiparticle – a repulsive polaron – in an ultracold quantum gas. The scientists have published their results in the online issue of the journal Nature. http://phys.org/news256995339.html Physics - Quantum Physics 2012-05-23T13:00:05-07:00 (Phys.org) -- In a paper published in the May 20, 2012 edition of the journal Nature Physics, a research group from the Department of Physics and Astronomy at Stony Brook University reports the development and demonstration of a novel probe for atomic quantum matter. The paper, “Probing an Ultracold-Atom Crystal with Matter Waves," describes a proof-of-principle experiment on the diffraction of atomic de Broglie waves from a strongly correlated gas of atoms held in an optical lattice. http://phys.org/news256967606.html Physics - Quantum Physics 2012-05-23T05:30:01-07:00 Francesca Ferlaino’s research team at the University of Innsbruck is the first to successfully create a condensate of the exotic element erbium. The Innsbruck experimental physicists hold the world record in attaining the first Bose-Einstein condensates of different chemical elements. http://phys.org/news256892364.html Physics - Quantum Physics 2012-05-22T07:59:55-07:00 Quantum physics promises faster and more powerful computers, but quantum versions of basic logic functions are still needed to bring this technology to fruition. Researchers from the University of Cambridge and Toshiba Research Europe Ltd. have taken one step toward this goal by creating an all-semiconductor quantum logic gate, a controlled-NOT (CNOT) gate. They achieved this breakthrough by coaxing nanodots to emit single photons of light on demand. http://phys.org/news256563091.html Physics - Quantum Physics 2012-05-18T12:31:40-07:00 (Phys.org) -- In a bit of inspired research, a diverse team of researchers has devised a means for measuring the time it takes for an electron to tunnel through a barrier. Led by Israel's Weizmann Institute of Science, Dror Shafir, the team as they describe in their paper published in the journal Nature used one laser to lower a barrier allowing an electron to escape via tunneling from its Helium atom, and another to prod it back again and in the process were able to measure the time it took to do so. http://phys.org/news256544128.html Physics - Quantum Physics 2012-05-18T07:15:49-07:00 (Phys.org) -- The main technical difficulty in building a quantum computer could soon be the thing that makes it possible to build one, according to new research from The Australian National University. http://phys.org/news256538114.html Physics - Quantum Physics 2012-05-18T05:35:35-07:00 EU-funded scientists made advances in the development of a hybrid quantum system (HQS) by combining different quantum technologies. http://phys.org/news256379722.html Physics - Quantum Physics 2012-05-16T09:35:50-07:00 (Phys.org) -- A team of Chinese physicists has broken the distance record for teleporting qubits, extending it from 16 to 97 kilometers. They did so, as they explain in their paper uploaded to the preprint server arXiv, using the phenomenon known as entanglement. http://phys.org/news256200102.html Physics - Quantum Physics 2012-05-14T07:43:18-07:00 (Phys.org) -- Back in November, a paper posted to a preprint server arXiv by three British physicists prompted some heated debate regarding the nature of the quantum wave function, a probability function that physicists use to help them better understand the quantum world. At the time, the three refrained from joining in on subsequent discussions on the paper due to pending acceptance of the paper in the journal Nature Physics. Now that the paper has been accepted and printed, the three, Matthew Pusey, Jonathan Barrett and Terry Rudolph are openly defending their assertion that the wave function is real, not some function that is dependent on available information for the user when using it. http://phys.org/news255774529.html Physics - Quantum Physics 2012-05-09T09:29:04-07:00 (Phys.org) -- In the natural world, it seems randomness is all around. Walk through a forest for example and it appears completely random, despite the fact that natural patterns emerge at almost every turn. In the human world, randomness is valued by all manner of people in a variety of circumstances, from testers of systems to ensure that weaknesses show up before products are sold to the public, to cryptologists, to those that run casinos where randomness ensures the house will win far more often than not. Unfortunately, guaranteeing true randomness is not something that comes easy. Take the lowly coin toss for example. A slight difference in weight on the “heads” side may cause the “tales” side to turn up a hundredth of a percentage point more often. Because of this, new work by a pair of physicists is catching the attention of people across a wide swath of interests. http://phys.org/news255684928.html Physics - Quantum Physics 2012-05-08T08:35:50-07:00 Simulations of reality would require less memory on a quantum computer than on a classical computer, new research from scientists at the University of Bristol, published in Nature Communications, has shown. http://phys.org/news255320809.html Physics - Quantum Physics 2012-05-04T03:27:05-07:00 In the age of high-speed computing, the photon is king. However, producing the finely tuned particles of light is a complex and time-consuming process, until now. http://phys.org/news255013249.html Physics - Quantum Physics 2012-04-30T14:01:16-07:00 Physicists at the National Institute of Standards and Technology have built a quantum simulator that can engineer interactions among hundreds of quantum bits (qubits) -- 10 times more than previous devices. As described in the April 26 issue of Nature, the simulator has passed a series of important benchmarking tests and scientists are poised to study problems in material science that are impossible to model on conventional computers. http://phys.org/news254576031.html Physics - Quantum Physics 2012-04-25T13:00:01-07:00 (Phys.org) -- At the heart of quantum mechanics lies the wave function, a probability function used by physicists to understand the nanoscale world. Using the wave function, physicists can calculate a system's future behavior, but only with a certain probability. This inherently probabilistic nature of quantum theory differs from the certainty with which scientists can describe the classical world, leading to a nearly century-long debate on how to interpret the wave function: does it representative objective reality or merely the subjective knowledge of an observer? In a new paper, physicists Roger Colbeck of the Perimeter Institute in Waterloo, Ontario, and Renato Renner who is based at ETH Zurich, Switzerland, have presented an argument strongly in favor of the objective reality of the wave function, which could lead to a better understanding of the fundamental meaning of quantum mechanics. http://phys.org/news254575239.html Physics - Quantum Physics 2012-04-25T12:21:12-07:00 Physicists of the group of Prof. Anton Zeilinger at the Institute for Quantum Optics and Quantum Information (IQOQI), the University of Vienna, and the Vienna Center for Quantum Science and Technology (VCQ) have, for the first time, demonstrated in an experiment that the decision whether two particles were in an entangled or in a separable quantum state can be made even after these particles have been measured and may no longer exist. Their results will be published this week in the journal Nature Physics. http://phys.org/news254399591.html Physics - Quantum Physics 2012-04-23T11:33:23-07:00 A research team at the University of Pittsburgh is developing quantum-computing algorithms to better model turbulent combustion in aerospace applications. http://phys.org/news253988418.html Physics - Quantum Physics 2012-04-18T17:20:38-07:00 (Phys.org) -- In optical communication systems, the overall performance depends on the strategy used to transmit photons from one location to another. In previous attempts to optimize this performance, scientists found that there is a trade-off between three transmission strategies: classical communication (measured in bits), quantum communication (measured in qubits), and shared entanglement (measured in ebits). But previous research has also suggested that the benefits of using this knowledge to implement “trade-off coding” strategies were too small and the coding too complex to have practical value. Now in a new study, scientists have found that trade-off coding strategies can in fact have remarkable performance gains when communicating over an optical channel compared with other traditional optical communication strategies. The finding could lead to transmitting classical and quantum information simultaneously at much higher rates than is possible with other techniques. http://phys.org/news253633964.html Physics - Quantum Physics 2012-04-16T09:00:02-07:00 (Phys.org) -- Research into quantum bits (qubits) for use in a quantum computer has become tied to entanglement, the still mysterious phenomenon whereby subatomic particles exist in an entangled state such that any change to one happens simultaneously to the other, without communication or the passage of time. The reason entanglement of qubits is so important to the future of a quantum computer is because they are able to represent both a “1” and “0” state at the same time and because actions that cause a change in one entangled particle also cause the same change in its partner, theoretically allowing for processing speeds to increase exponentially when adding more entangled qubits. Thus far though, attempts to create entangled particles inside of a semiconductor material have been difficult to measure, and thus verify, due to their short lives. http://phys.org/news253530437.html Physics - Quantum Physics 2012-04-13T10:40:01-07:00 (Phys.org) -- A team of scientists at the Max Planck Institute of Quantum Optics realizes a first elementary quantum network based on interfaces between single atoms and photons. http://phys.org/news253383260.html Physics - Quantum Physics 2012-04-11T17:14:42-07:00 (Phys.org) -- While factoring an integer is a simple problem when the integer is small, the complexity of factorization greatly increases as the integer increases. When the integer grows to more than 100,000 or so digits, the problem reaches a point at which it becomes too complex to solve using classical computing methods. But quantum computers, with their use of entanglement and superposition, can theoretically factor a number of any size. However, the largest number that has been factored on a quantum processor so far is 21. Now in a new study, physicists have set a new record for quantum factorization by developing the first quantum algorithm that can factor a three-digit integer, 143, into its prime factors, 11 and 13. http://phys.org/news253373526.html Physics - Quantum Physics 2012-04-11T14:32:42-07:00 (Phys.org) -- Researchers at The Australian National University have developed the fastest random number generator in the world by listening to the 'sounds of silence'. http://phys.org/news253346500.html Physics - Quantum Physics 2012-04-11T07:01:50-07:00 Scientists at the Cavendish Laboratory in Cambridge have used light to help push electrons through a classically impenetrable barrier. While quantum tunnelling is at the heart of the peculiar wave nature of particles, this is the first time that it has been controlled by light. Their research is published today, 05 April, in the journal Science. http://phys.org/news252844791.html Physics - Quantum Physics 2012-04-05T14:00:11-07:00 A protocol for controlling quantum information pioneered by researchers at UC Santa Barbara, the Kavli Institute of Nanoscience in Delft, the Netherlands, and the Ames Laboratory at Iowa State University could open the door to larger-scale, more accurate quantum computations. Their findings, in a paper titled "Decoherence-protected quantum gates for a hybrid solid-state spin register," are published in the current issue of the journal Nature. http://phys.org/news252778016.html Physics - Quantum Physics 2012-04-04T17:07:16-07:00 Diamonds are forever – or, at least, the effects of this diamond on quantum computing may be. A team that includes scientists from USC has built a quantum computer in a diamond, the first of its kind to include protection against "decoherence" – noise that prevents the computer from functioning properly. http://phys.org/news252773996.html Physics - Quantum Physics 2012-04-04T16:00:21-07:00