Free Newsletters - Space News - Defense Alert - Environment Report - Energy Monitor
. 24/7 Space News .




TIME AND SPACE
Mapping the optimal route between 2 quantum states
by Staff Writers
Rochester NY (SPX) Aug 01, 2014


Measurement data showing the comparison with the 'most likely' path (in red) between initial and final quantum states (black dots). The measurements are shown on a representation referred to as a Bloch sphere. Image courtesy Areeya Chantasri.

As a quantum state collapses from a quantum superposition to a classical state or a different superposition, it will follow a path known as a quantum trajectory.

For each start and end state there is an optimal or "most likely" path, but it is not as easy to predict the path or track it experimentally as a straight-line between two points would be in our everyday, classical world.

In a new paper featured this week on the cover of Nature, scientists from the University of Rochester, University of California at Berkeley and Washington University in St. Louis have shown that it is possible to track these quantum trajectories and compare them to a recently developed theory for predicting the most likely path a system will take between two states.

Andrew N. Jordan, professor of physics at the University of Rochester and one of the authors of the paper, and his group had developed this new theory in an earlier paper. The results published this week show good agreement between theory and experiment.

For their experiment, the Berkeley and Washington University teams devised a superconducting qubit with exceptional coherence properties, permitting it to remain in a quantum superposition during the continuous monitoring. The experiment actually exploited the fact that any measurement will perturb a quantum system.

This means that the optimal path will come about as a result of the continuous measurement and how the system is being driven from one quantum state to another.

Kater Murch, co-author and assistant professor at Washington University in St. Louis, explained that a key part of the experiment was being able to measure each of these trajectories while the system was changing, something that had not been possible until now.

Jordan compares the experiment to watching butterflies make their way one by one from a cage to nearby trees. "Each butterfly's path is like a single run of the experiment," said Jordan.

"They are all starting from the same cage, the initial state, and ending in one of the trees, each being a different end state."

By watching the quantum equivalent of a million butterflies make the journey from cage to tree, the researchers were in effect able to predict the most likely path a butterfly took by observing which tree it landed on (known as post-selection in quantum physics measurements), despite the presence of a wind, or any disturbance that affects how it flies (which is similar to the effect measuring has on the system).

"The experiment demonstrates that for any choice of final quantum state, the most likely or 'optimal path' connecting them in a given time can be found and predicted," said Jordan. "This verifies the theory and opens the way for active quantum control techniques." He explained that only if you know the most likely path is it possible to set up the system to be in the desired state at a specific time.

.


Related Links
University of Rochester
Understanding Time and Space






Comment on this article via your Facebook, Yahoo, AOL, Hotmail login.

Share this article via these popular social media networks
del.icio.usdel.icio.us DiggDigg RedditReddit GoogleGoogle




Memory Foam Mattress Review
Newsletters :: SpaceDaily :: SpaceWar :: TerraDaily :: Energy Daily
XML Feeds :: Space News :: Earth News :: War News :: Solar Energy News





TIME AND SPACE
Scientists separate a particle from its properties
Grenoble, France (SPX) Jul 31, 2014
Researchers from the Vienna University of Technology have performed the first separation of a particle from one of its properties. The study, carried out at the Institute Laue-Langevin (ILL) and published in Nature Communications, showed that in an interferometer a neutron's magnetic moment could be measured independently of the neutron itself, thereby marking the first experimental observation ... read more


TIME AND SPACE
Manned Moon Mission to Cost Russia $2.8 Bln

Tidal forces gave moon its shape

Riddle of bulging Moon solved at last

China's biggest moon challenge: returning to earth

TIME AND SPACE
NASA Mars Rover Curiosity Nears Mountain-Base Outcrop

Absence of Russia Instrument On NASA Mars Rover Not Political

Mars 2020 rover will carry tools to make oxygen

NASA Mars Curiosity Rover: Two Years and Counting on Red Planet

TIME AND SPACE
NEEMO 18 Aquanauts Complete Underwater Mission

Orion Tests Set Stage for Mission

NASA's IBEX and Voyager spacecraft drive advances in outer heliosphere research

Captains of industry explore space's new frontiers

TIME AND SPACE
China's Circumlunar Spacecraft Unmasked

China to launch HD observation satellite this year

Lunar rock collisions behind Yutu damage

China's Fast Track To Circumlunar Mission

TIME AND SPACE
Europe's Fifth and Final Resupply Ship Launches to Station

Science and Spacesuit Work While ATV-5 Preps for Launch

Russian Cargo Craft Launches for 6-Hour Trek to ISS

ISS Crew Opens Cargo Ship Hatch, Preps for CubeSat Deployment

TIME AND SPACE
AsiaSat 8 Successfully Lifts Off

SpaceX launches AsiaSat8 into orbit via Falcon 9 rocket

United Launch Alliance Launches Two Rockets in Just Four Days

United Launch Alliance Marks 85th Successful Launch

TIME AND SPACE
Young binary star system may form planets with weird and wild orbits

Hubble Finds Three Surprisingly Dry Exoplanets

Astronomers come up dry in search for water on exoplanets

Hubble Finds Three Surprisingly Dry Exoplanets

TIME AND SPACE
NASA Experts, Russia Sign Radiation Safety Protocol Despite Sanctions

Center for Orbital Debris Education and Research Recruits Industrial Affiliates

Military training and simulation revenues to remain steady

Printing the Metals of the Future




The content herein, unless otherwise known to be public domain, are Copyright 1995-2014 - Space Media Network. All websites are published in Australia and are solely subject to Australian law and governed by Fair Use principals for news reporting and research purposes. AFP, UPI and IANS news wire stories are copyright Agence France-Presse, United Press International and Indo-Asia News Service. ESA news reports are copyright European Space Agency. All NASA sourced material is public domain. Additional copyrights may apply in whole or part to other bona fide parties. Advertising does not imply endorsement, agreement or approval of any opinions, statements or information provided by Space Media Network on any Web page published or hosted by Space Media Network. Privacy Statement All images and articles appearing on Space Media Network have been edited or digitally altered in some way. Any requests to remove copyright material will be acted upon in a timely and appropriate manner. Any attempt to extort money from Space Media Network will be ignored and reported to Australian Law Enforcement Agencies as a potential case of financial fraud involving the use of a telephonic carriage device or postal service.