Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Quantum paradox directly observed -- a milestone in quantum mechanics

05.03.2009
In quantum mechanics, a vanguard of physics where science often merges into philosophy, much of our understanding is based on conjecture and probabilities, but a group of researchers in Japan has moved one of the fundamental paradoxes in quantum mechanics into the lab for experimentation and observed some of the 'spooky action of quantum mechanics' directly.

Hardy's Paradox, the axiom that we cannot make inferences about past events that haven't been directly observed while also acknowledging that the very act of observation affects the reality we seek to unearth, poses a conundrum that quantum physicists have sought to overcome for decades. How do you observe quantum mechanics, atomic and sub-atomic systems that are so small-scale they cannot be described in classical terms, when the act of looking at them changes them permanently?

In a journal paper published in the New Journal of Physics, 'Direct observation of Hardy's paradox by joint weak measurement with an entangled photon pair', today, Wednesday, 4 March, authored by Kazuhiro Yokota, Takashi Yamamoto, Masato Koashi and Nobuyuki Imoto from the Graduate School of Engineering Science at Osaka University and the CREST Photonic Quantum Information Project in Kawaguchi City, the research group explains how they used a measurement technique that has an almost imperceptible impact on the experiment which allows the researchers to compile objectively provable results at sub-atomic scales.

The experiment, based on Lucien Hardy's thought experiment, which follows the paths of two photons using interferometers, instruments that can be used to interfere photons together, is believed to throw up contradictory results that do not conform to our classical understanding of reality. Although Hardy's Paradox is rarely refuted, it was only a thought experiment until recently.

Using an entangled pair of photons and an original but complicated method of weak measurement that does not interfere with the path of the photons, a significant step towards harnessing the reality of quantum mechanics has been taken by these researchers in Japan.

As the researchers write, "Unlike Hardy's original argument, our demonstration reveals the paradox by observation, rather than inference. We believe the demonstrated joint weak measurement is useful not only for exploiting fundamental quantum physics, but also for various applications such as quantum metrology and quantum information technology."

Joe Winters | EurekAlert!
Further information:
http://www.iop.org

More articles from Physics and Astronomy:

nachricht Computer model predicts how fracturing metallic glass releases energy at the atomic level
20.07.2018 | American Institute of Physics

nachricht What happens when we heat the atomic lattice of a magnet all of a sudden?
18.07.2018 | Forschungsverbund Berlin

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: Future electronic components to be printed like newspapers

A new manufacturing technique uses a process similar to newspaper printing to form smoother and more flexible metals for making ultrafast electronic devices.

The low-cost process, developed by Purdue University researchers, combines tools already used in industry for manufacturing metals on a large scale, but uses...

Im Focus: First evidence on the source of extragalactic particles

For the first time ever, scientists have determined the cosmic origin of highest-energy neutrinos. A research group led by IceCube scientist Elisa Resconi, spokesperson of the Collaborative Research Center SFB1258 at the Technical University of Munich (TUM), provides an important piece of evidence that the particles detected by the IceCube neutrino telescope at the South Pole originate from a galaxy four billion light-years away from Earth.

To rule out other origins with certainty, the team led by neutrino physicist Elisa Resconi from the Technical University of Munich and multi-wavelength...

Im Focus: Magnetic vortices: Two independent magnetic skyrmion phases discovered in a single material

For the first time a team of researchers have discovered two different phases of magnetic skyrmions in a single material. Physicists of the Technical Universities of Munich and Dresden and the University of Cologne can now better study and understand the properties of these magnetic structures, which are important for both basic research and applications.

Whirlpools are an everyday experience in a bath tub: When the water is drained a circular vortex is formed. Typically, such whirls are rather stable. Similar...

Im Focus: Breaking the bond: To take part or not?

Physicists working with Roland Wester at the University of Innsbruck have investigated if and how chemical reactions can be influenced by targeted vibrational excitation of the reactants. They were able to demonstrate that excitation with a laser beam does not affect the efficiency of a chemical exchange reaction and that the excited molecular group acts only as a spectator in the reaction.

A frequently used reaction in organic chemistry is nucleophilic substitution. It plays, for example, an important role in in the synthesis of new chemical...

Im Focus: New 2D Spectroscopy Methods

Optical spectroscopy allows investigating the energy structure and dynamic properties of complex quantum systems. Researchers from the University of Würzburg present two new approaches of coherent two-dimensional spectroscopy.

"Put an excitation into the system and observe how it evolves." According to physicist Professor Tobias Brixner, this is the credo of optical spectroscopy....

All Focus news of the innovation-report >>>

Anzeige

Anzeige

VideoLinks
Industry & Economy
Event News

Leading experts in Diabetes, Metabolism and Biomedical Engineering discuss Precision Medicine

13.07.2018 | Event News

Conference on Laser Polishing – LaP: Fine Tuning for Surfaces

12.07.2018 | Event News

11th European Wood-based Panel Symposium 2018: Meeting point for the wood-based materials industry

03.07.2018 | Event News

 
Latest News

A smart safe rechargeable zinc ion battery based on sol-gel transition electrolytes

20.07.2018 | Power and Electrical Engineering

Reversing cause and effect is no trouble for quantum computers

20.07.2018 | Information Technology

Princeton-UPenn research team finds physics treasure hidden in a wallpaper pattern

20.07.2018 | Materials Sciences

VideoLinks
Science & Research
Overview of more VideoLinks >>>