http://www.physorg.com/physics-news/quantum-physics/ en-us PhysOrg Team PhysOrg.com provides the latest news on quantum physics, wave particle duality, quantum theory, quantum mechanics, quantum entanglement, quantum teleportation, and quantum computing. Quantum computing promises ultra-fast communication, computation and more powerful ways to encrypt sensitive information. But trying to use quantum states as carriers of information is an extremely delicate business. Now two physicists have shown, mathematically, how to gently tease out unwanted knots in quantum communication, while keeping the information intact. Their work is reported in the current issue of Physical Review Letters and highlighted with a Viewpoint in Physics. http://www.physorg.com/news178211021.html Physics - Quantum Physics 2009-11-23T15:20:01-07:00 The dusty boxes that line the walls of Jeff Barrett's UC Irvine office mark a high point in his academic career. Their contents: pages and pages of notes, most more than 50 years old, penned by late quantum theorist Hugh Everett III. http://www.physorg.com/news178207143.html Physics - Quantum Physics 2009-11-23T13:59:29-07:00 Physicists at UC Santa Barbara have made an important advance in electrically controlling quantum states of electrons, a step that could help in the development of quantum computing. The work is published online today on the Science Express Web site. http://www.physorg.com/news177938057.html Physics - Quantum Physics 2009-11-20T11:18:55-07:00 To exploit the quantum world to the fullest, a key commodity is entanglement -the spooky, distance-defying link that can form between objects such as atoms even when they are completely shielded from one another. Now, physicists at the Joint Quantum Institute (JQI), a collaborative organization of the National Institute of Standards and Technology and the University of Maryland, have developed a promising new source of entangled photons using quantum dots tweaked with a laser. The JQI technique may someday enable more compact and convenient sources of entangled photon pairs than presently available for quantum information applications such as the distribution of "quantum keys" for encrypting sensitive messages. http://www.physorg.com/news177763808.html Physics - Quantum Physics 2009-11-18T10:50:39-07:00 Everybody loves a race to the wire, even when the result is a tie. The great irony is the ultraprecise clocks that could result from this competition could probably break any tie. http://www.physorg.com/news177694595.html Physics - Quantum Physics 2009-11-17T15:37:16-07:00 Physicists at the National Institute of Standards and Technology have demonstrated the first "universal" programmable quantum informationprocessor able to run any program allowed by quantum mechanics -- the rules governing the submicroscopic world -- using two quantum bits (qubits) of information. The processor could be a module in a future quantum computer, which theoretically could solve some important problems that are intractable today. http://www.physorg.com/news177515046.html Physics - Quantum Physics 2009-11-15T13:45:25-07:00 (PhysOrg.com) -- In a recently published paper, Aram Harrow at the University of Bristol and colleagues from MIT in the United States have discovered a quantum algorithm that solves large problems much faster than conventional computers can. http://www.physorg.com/news177011105.html Physics - Quantum Physics 2009-11-09T18:20:02-07:00 In an international first, scientists from the Institute of Quantum Optics and Quantum Information (IQOQI, Austria) produced a Bose-Einstein condensate of the alkaline-earth element strontium, thus narrowly winning an international competition between many first-rate scientific groups. Choosing the isotope 84Sr, which has received little attention so far, proved to be the right choice for the breakthrough. It can now be regarded as an ideal candidate for future experiments with atomic two-electron systems. http://www.physorg.com/news176994672.html Physics - Quantum Physics 2009-11-09T13:11:51-07:00 (PhysOrg.com) -- Physicists at Harvard University have created a quantum gas microscope that can be used to observe single atoms at temperatures so low the particles follow the rules of quantum mechanics, behaving in bizarre ways. http://www.physorg.com/news176569616.html Physics - Quantum Physics 2009-11-04T15:07:42-07:00 (PhysOrg.com) -- Many scientists believe that quantum entanglement is required in order for effective quantum computing. Entanglement takes place when there is a connection that exists between two objects - even when they are spatially separated - that allows what happens to one to happen to the other. The link is such that each entangled object cannot be adequately described without its counterpart. So far, entangling qubits for practical use has been difficult, since scientists want to be able to entangle several qubits at once. http://www.physorg.com/news176364815.html Physics - Quantum Physics 2009-11-02T11:20:01-07:00 (PhysOrg.com) -- For more than 50 years, physicists have been intrigued by the concept of closed time-like curves (CTCs). Because a CTC returns to its starting point, it raises the possibility of traveling backward in time. More recently, physicists have theorized that CTC-assisted computers could enable ideal quantum state discrimination, and even make classical computers (with CTCs) equally as powerful as quantum computers. However, a new study argues that CTCs, if they exist, might actually provide much less computational benefit than previously thought. http://www.physorg.com/news175421039.html Physics - Quantum Physics 2009-10-22T10:40:01-07:00 Key Laboratory of Quantum Information (CAS), University of Science and Technology of China has recently demonstrated a metropolitan Quantum Cryptography Network (QCN) for Government Administration in Wuhu, China. The project is reported in Volume 54, Issue 17 (September, 2009) of the Chinese Science Bulletin authored by Fang-xing Xu et al. http://www.physorg.com/news174891921.html Physics - Quantum Physics 2009-10-16T06:06:41-07:00 In the quest for smaller, faster computer chips, researchers are increasingly turning to quantum mechanics -- the exotic physics of the small. The problem: the manufacturing techniques required to make quantum devices have been equally exotic. That is, until now. http://www.physorg.com/news174833014.html Physics - Quantum Physics 2009-10-15T13:44:35-07:00 (PhysOrg.com) -- (PhysOrg.com) -- A team of scientists from the Max Planck Institute of Quantum Optics and the Ludwig Maximilians University have succeeded in applying a novel optical method to nano-mechanical oscillators. New fabrication techniques have enabled the development of on-chip mechanical elements whose dimensions are on the nanometer scale. Their application, however, has been limited by the lack of sufficiently sensitive techniques for measuring the motion of these tiny devices. http://www.physorg.com/news174757411.html Physics - Quantum Physics 2009-10-14T16:50:59-07:00 (PhysOrg.com) -- What if atoms could be used to perform the functions currently the province of electronic devices? The goal of atomtronics is to do just that by creating analogues to the common items found in electronic devices. Ron Pepino, a graduate student at JILA and the University of Colorado, believes that he and his colleagues have found a way to create the atomtronic versions of diode and transistor circuits. The work of Pepino, Cooper, Anderson and Holland is described in Physical Review Letters: "Atomtronic Circuits of Diodes and Transistors." http://www.physorg.com/news174303837.html Physics - Quantum Physics 2009-10-09T10:44:44-07:00 (PhysOrg.com) -- In recent years, quantum computers have lost some of their luster. In the 1990s, it seemed that they might be able to solve a class of difficult but common problems - the so-called NP-complete problems - exponentially faster than classical computers. Now, it seems that they probably can't. In fact, until this week, the only common calculation where quantum computation promised exponential gains was the factoring of large numbers, which isn't that useful outside cryptography. http://www.physorg.com/news174286879.html Physics - Quantum Physics 2009-10-09T06:01:53-07:00 Chaotic behavior is the rule, not the exception, in the world we experience through our senses, the world governed by the laws of classical physics. http://www.physorg.com/news174143570.html Physics - Quantum Physics 2009-10-07T14:13:42-07:00 (PhysOrg.com) -- For the first time, physicists have demonstrated the quantum entanglement of three light beams, all of different wavelengths. Entanglement of two light beams of different wavelengths has already been demonstrated, but the researchers explain that going beyond two beams is important since three beams can serve as connections at the nodes of a quantum network. http://www.physorg.com/news174133022.html Physics - Quantum Physics 2009-10-07T11:17:35-07:00 Exploiting quantum mechanics for transmitting information is a tantalizing possibility because it promises secure, high speed communications. Unfortunately, the fragility of methods for storing and sending quantum information has so far frustrated the enterprise. Now a team of physicists in Sweden and Poland have shown that photons that encode data have strength in numbers. Their experiment is reported in Physical Review Letters and Physical Review A and highlighted in the October 5 issue of Physics. http://www.physorg.com/news173964594.html Physics - Quantum Physics 2009-10-05T12:30:22-07:00 A Kansas State University physicist is continuing his study of atomic collisions with the help of a National Science Foundation grant awarded under the American Recovery and Reinvestment Act. http://www.physorg.com/news173529452.html Physics - Quantum Physics 2009-09-30T11:50:01-07:00 (PhysOrg.com) -- For the first time, physicists have experimentally demonstrated a four-qubit bound-entangled state - a peculiar form of entanglement that cannot be distilled (optimized) by the usual means. However, the scientists have found a novel method for distilling the entanglement by working with two qubits at a time. As the researchers explain, the special properties of bound entanglement could make it a useful quantum resource for new multiparty communication and secret sharing schemes, and the results could also contribute to a deeper understanding of the foundations of quantum mechanics. http://www.physorg.com/news173517599.html Physics - Quantum Physics 2009-09-30T10:00:01-07:00 (PhysOrg.com) -- By greatly amplifying one photon from an entangled photon pair, physicists have theoretically shown that human eyes can be used as detectors to observe quantum effects. Usually, detecting quantum phenomena requires sensitive photon detectors or similar technology, keeping the quantum world far removed from our everyday experience. By showing that it`s possible to perform quantum optics experiments with human eyes as detectors, the physicists can bring quantum phenomena closer to the macroscopic level and to everyday life. http://www.physorg.com/news173423784.html Physics - Quantum Physics 2009-09-29T09:10:03-07:00 (Santa Barbara, Calif.) -- Physicists at UC Santa Barbara have made an important advance in quantum mechanics using a superconducting electrical circuit. The finding is reported in this week's issue of the journal Nature. http://www.physorg.com/news172936800.html Physics - Quantum Physics 2009-09-23T15:00:50-07:00 (PhysOrg.com) -- There's nothing University of Nebraska-Lincoln physicist Herman Batelaan likes more than a challenge. And there are few areas of science more challenging than working at the sub-atomic, or quantum, world, where the laws of physics are different from those of our macro world. http://www.physorg.com/news172919873.html Physics - Quantum Physics 2009-09-23T10:18:51-07:00 (PhysOrg.com) -- Diamonds, it has long been said, are a girl's best friend. But a research team including a physicist from the National Institute of Standards and Technology has recently found that the gems might turn out to be a patient's best friend as well. http://www.physorg.com/news172862154.html Physics - Quantum Physics 2009-09-22T18:16:51-07:00 Air Force Office of Scientific Research(AFOSR)-supported physicists at the University of Michigan are developing innovative components for quantum, or super-fast, computers that will improve security for data storage and transmission. http://www.physorg.com/news171731312.html Physics - Quantum Physics 2009-09-09T16:20:02-07:00 (PhysOrg.com) -- While researchers have already demonstrated the building blocks for few-bit quantum computers, scaling these systems up to large quantum computers remains a challenge. One of the biggest problems is developing physical systems that can reliably store thousands of qubits, and enabling bits and pairs to be addressed individually for gate operations. http://www.physorg.com/news171705608.html Physics - Quantum Physics 2009-09-09T09:02:02-07:00 (PhysOrg.com) -- A primitive quantum computer that uses single particles of light (photons) whizzing through a silicon chip has performed its first mathematical calculation. This is the first time a calculation has been performed on a photonic chip and it is major step forward in the quest to realise a super-powerful quantum computer. http://www.physorg.com/news171213314.html Physics - Quantum Physics 2009-09-03T16:15:49-07:00 In a recent study, Professor of Physics and Astronomy Miles Blencowe and his colleagues proposed a new way of creating a reproduction black hole in the laboratory. http://www.physorg.com/news170617671.html Physics - Quantum Physics 2009-08-27T18:48:28-07:00 Does an exciting but controversial new model of quantum gravity reproduce Einstein's theory of general relativity? Scientists at Texas A&M University in the US explore this question in a paper appearing in Physical Review Letters and highlighted with a Viewpoint in the August 24th issue of Physics. http://www.physorg.com/news170333445.html Physics - Quantum Physics 2009-08-24T12:20:01-07:00