Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

A quantum computer breakthrough and dark matter stars

30.11.2007
Highlights in this issue: A quantum computer breakthrough and dark matter stars.

Quantum Computer Breakthrough

Chao-Yang Lu, Daniel E. Browne, Tao Yang, and Jian-Wei Pan Physical Review Letters (forthcoming) and B. P. Lanyon, T. J. Weinhold, N. K. Langford, M. Barbieri, D. F. V. James , A. Gilchrist, and A. G. White

Physical Review Letters (forthcoming)

Two research groups have independently managed to experimentally solve a mathematical problem with light-based quantum computers. The simultaneous achievements appear to be the first experimental demonstrations of true (though rudimentary) quantum mechanical computations. Both groups manipulated quantum mechanically entangled photons to calculate the prime factors of the number 15.

Although the physicists could have gotten the answer to the problem much more easily by querying an average elementary school child, the method both groups used involved a quantum mechanical approach commonly known as Shor's algorithm. Previous theoretical work has shown that the algorithm could potentially crack cryptographic codes that are practically unbreakable with non-quantum mechanical (classical) computers.

While there's no great need to factor numbers as small as 15, the research demonstrates that quantum computation is feasible with existing technology and could in principle be scaled up to tackle problems that would take longer than the age of the universe to solve with any classical computer, but would require only minutes on a quantum computer.

In addition to factoring large numbers and solving other challenging mathematical problems, quantum computers based on the work of these two groups could help model quantum mechanical problems in physics and chemistry (see http://xxx.lanl.gov/ftp/arxiv/papers/0710/0710.0278.pdf for an example of a quantum simulator experiment by C.-Y. Lu et al.), and lead to ultra high speed searching algorithms.

Chao-Yang Lu and his group are currently expanding on their work by trying to manipulate larger numbers of quantum bits. In the long run, they plan to add quantum memory to their quantum computers, which could further increase the number of photons they can control. In addition, because the loss of photons is a huge problem for light-based quantum computation, they are working on some basic quantum codes that can protect the quantum information from photon loss error. These sorts of issues are crucial in the effort to scale up photonic quantum computation. - JR

Dark Matter Stars

Douglas Spolyar, Katherine Freese, and Paolo Gondolo Physical Review Letters (forthcoming)

Before stars were fueled by nuclear fusion, they may have been fueled by dark matter. Researchers have theorized that "Dark Stars" may have been supported by the huge release of energy from dark matter annihilation (i.e. the release of energy that comes when matter and antimatter encounter each other) in the early universe. The physicists from UC Santa Cruz, UM Ann Arbor, and the University of Utah believe that despite many theories stating otherwise, dark matter did have an effect on the first stars in the universe.

The release of energy from dark matter/anti-dark matter annihilation may have prevented the first proto-stars from collapsing and beginning fusion, but in turn could have heated a star¿s core enough to support it. This would change the time scale of the formation of second generation stars, the appearance of elements like nitrogen, carbon, and oxygen in our universe, and other aspects of stellar evolution.

Products of the annihilation, such as neutrinos, gamma-rays, or antimatter may make these dark stars or their remnants detectable. Although stars composed of dark matter are likely to be much dimmer than normal stars, they may produce some light. The next step for researchers will be to determine how much visible light the dark stars give off, and how long they survive. Dark stars may have died out millions of years ago, or they may still exist today.

The idea of dark stars relies on the Lightest Super symmetric Particle (LSP), a highly favored candidate for particles that make up dark matter. The properties of the LSPs are consistent with current information about dark matter in the universe. Many physicists are hopeful that new experiments in particle colliders will soon yield more discoveries on the nature of dark matter, and perhaps offer insight into the possibility of dark stars in the early universe. - CC

Contact: James Riordon
American Physical Society
riordon@aps.org
301-209-3238

James Riordon | American Physical Society
Further information:
http://www.aps.org

More articles from Physics and Astronomy:

nachricht Pulses of electrons manipulate nanomagnets and store information
21.07.2017 | American Institute of Physics

nachricht Vortex photons from electrons in circular motion
21.07.2017 | National Institutes of Natural Sciences

All articles from Physics and Astronomy >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: Manipulating Electron Spins Without Loss of Information

Physicists have developed a new technique that uses electrical voltages to control the electron spin on a chip. The newly-developed method provides protection from spin decay, meaning that the contained information can be maintained and transmitted over comparatively large distances, as has been demonstrated by a team from the University of Basel’s Department of Physics and the Swiss Nanoscience Institute. The results have been published in Physical Review X.

For several years, researchers have been trying to use the spin of an electron to store and transmit information. The spin of each electron is always coupled...

Im Focus: The proton precisely weighted

What is the mass of a proton? Scientists from Germany and Japan successfully did an important step towards the most exact knowledge of this fundamental constant. By means of precision measurements on a single proton, they could improve the precision by a factor of three and also correct the existing value.

To determine the mass of a single proton still more accurate – a group of physicists led by Klaus Blaum and Sven Sturm of the Max Planck Institute for Nuclear...

Im Focus: On the way to a biological alternative

A bacterial enzyme enables reactions that open up alternatives to key industrial chemical processes

The research team of Prof. Dr. Oliver Einsle at the University of Freiburg's Institute of Biochemistry has long been exploring the functioning of nitrogenase....

Im Focus: The 1 trillion tonne iceberg

Larsen C Ice Shelf rift finally breaks through

A one trillion tonne iceberg - one of the biggest ever recorded -- has calved away from the Larsen C Ice Shelf in Antarctica, after a rift in the ice,...

Im Focus: Laser-cooled ions contribute to better understanding of friction

Physics supports biology: Researchers from PTB have developed a model system to investigate friction phenomena with atomic precision

Friction: what you want from car brakes, otherwise rather a nuisance. In any case, it is useful to know as precisely as possible how friction phenomena arise –...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

Closing the Sustainability Circle: Protection of Food with Biobased Materials

21.07.2017 | Event News

»We are bringing Additive Manufacturing to SMEs«

19.07.2017 | Event News

The technology with a feel for feelings

12.07.2017 | Event News

 
Latest News

NASA looks to solar eclipse to help understand Earth's energy system

21.07.2017 | Earth Sciences

Stanford researchers develop a new type of soft, growing robot

21.07.2017 | Power and Electrical Engineering

Vortex photons from electrons in circular motion

21.07.2017 | Physics and Astronomy

VideoLinks
B2B-VideoLinks
More VideoLinks >>>