(Press-News.org) Completing the story they started by creating synthetic magnetic fields,* scientists from the Joint Quantum Institute (JQI), a collaboration of the National Institute of Standards and Technology (NIST) and the University of Maryland, have now made atoms act as if they were charged particles accelerated by electric fields.
Reported in the journal Nature Physics,** these synthetic electric fields make each atom in a gas act, individually, as if it were a charged particle, but collectively they remain neutral, uncharged particles. This dual personality will help researchers simulate and study fundamental electrical phenomena and may lead to a deeper understanding of exotic phenomena involving charged particles such as superconductivity, the flow of electricity without resistance, or the quantum Hall effect, used by NIST to create a standard of electrical resistance.
Some aspects of electricity are difficult to study because, although oppositely charged particles are attracted to one another, similarly charged particles are repelled by one another. To get around this, NIST physicist Ian Spielman and his colleagues realized that they could make atoms, which are typically electrically neutral, act as if they are charged particles in an electric field—extending their earlier method for making neutral atoms act like charged particles in a magnetic field.
The researchers create their synthetic electric field in an ultracold gas of several hundred thousand rubidium atoms. Using lasers, the team alters the atoms' energy-momentum relationship. This had the effect of transferring a bit of the lasers' momentum to the atoms, causing them to move. The force on each atom is physically identical—and mathematically equivalent—to what a charged particle would feel in an electric field.
So while the neutral atoms each experience the force of this synthetic electric field individually, they do not repel each other as would true charged particles in an ordinary electric field. This is analogous to an experienced group of dancers all following the moves of their instructor without getting in each other's way.
According to Spielman, this work may enable scientists to study the Hall effect, a phenomenon where an electromagnetic field can cause charged particles traveling through a conductor to experience a sideways force, which has of yet been unobserved in cold-atom systems. The work may also facilitate measurements of the atomic equivalents of electrical quantities such as resistance and inductance. For neutral atoms in synthetic electric fields, inductance is a measure of the energy that is stored as a result of the atoms' motion, and resistance is a measure of the dissipation, or energy loss, in the system. Measuring these quantities could provide insights into the properties of charged particles in analogous systems, including superconductors.
###
* See "JQI Researchers Create 'Synthetic Magnetic Fields' for Neutral Atoms," Dec. 15, 2009, at www.nist.gov/pml/div684/synthetic_121509.cfm.
** Y-J. Lin, R. L. Compton, K. Jiménez-García, W. D. Phillips, J. V. Porto and I. B. Spielman, A synthetic electric force acting on neutral atoms, Nature Physics. Published online March 20, 2011.
Charge it: Neutral atoms made to act like electrically charged particles
2011-04-02
ELSE PRESS RELEASES FROM THIS DATE:
McMaster vaccine has pet owners feline groovy
2011-04-02
Hamilton, ON (March 31, 2011) - Good-bye itching, watering eyes and sneezing. McMaster University researchers have developed a vaccine which successfully treats people with an allergy to cats.
Traditionally, frequent allergy shots have been considered the most effective way to bring relief – other than getting rid of the family pet -- for the eight to 10% of the population allergic to cats.
Both options – one difficult and costly, the other troubling - may now be tossed aside thanks to the work of immunologist Mark Larché, professor in the Department of Medicine in ...
Older and stronger: Progressive resistance training can build muscle, increase strength as we age
2011-04-02
VIDEO:
It's often thought that older adults must tolerate the strength and muscle loss that come with age. But analyses of current research by University of Michigan scientists reveal that not...
Click here for more information.
ANN ARBOR, Mich.—Getting older doesn't mean giving up muscle strength.
Not only can adults fight the battle of strength and muscle loss that comes with age, but the Golden Years can be a time to get stronger, say experts at the University of Michigan ...
Archaeologists investigate Iraqi marshes for origins of Mesopotamian cities
2011-04-02
Three National Science Foundation-supported researchers recently undertook the first non-Iraqi archaeological investigation of the Tigris-Euphrates delta in nearly 20 years. Archeologists Jennifer Pournelle and Carrie Hritz, with geologist Jennifer Smith, carried out the study late last year to look for links between wetland resources and the emergence of Mesopotamian cities.
"Mesopotamia"--Greek for "the land between the rivers"--is an area about 300 miles long and 150 miles wide straddling the Tigris and Euphrates rivers, which now run through Iraq, northeastern Syria, ...
It's good to have a shady side: sun and shade leaves play different roles in tree canopies
2011-04-02
Durham, NC —'Outer' tree canopy leaves influence the sunlight reaching inner canopy leaves by changing their shape, says a new study.
The shape and physiology of leaves within the tree canopy is not constant, and can vary depending on their position within the tree crown. This phenomenon is expected to have important consequences for how trees cope with stress and use resources.
A new study describes how the leaves in the outer canopy of olive trees can influence the light environment within the canopy by changing their shape, as more elongated leaves resulted in higher ...
NJIT professor uses math analytics to project 2011 Major League Baseball winners
2011-04-02
Philadelphia Phillies, St. Louis Cardinals and San Francisco Giants should win their divisions, while the Atlanta Braves will take the wild card slot in the National League (NL), according to NJIT's baseball guru Bruce Bukiet. http://www.njit.edu/news/experts/bukiet.php For over a decade, Bukiet, an associate professor and associate dean, has applied mathematical analysis to compute winning games for each Major League Baseball Team.
This year, he said that in the American League (AL), the New York Yankees and Boston Red Sox should tie for first place in the East, with ...
Study identifies promising target for AIDS vaccine
2011-04-02
BOSTON--A section of the AIDS virus's protein envelope once considered an improbable target for a vaccine now appears to be one of the most promising, new research by Dana-Farber Cancer Institute scientists indicates.
The section, a twisting strand of protein known as the V3 loop, is an attractive vaccine target because immune system antibodies aimed at the loop may offer protection against multiple genetic subtypes of HIV-1, the virus that causes AIDS. This is a key prerequisite of any AIDS vaccine because the viruses mutate rapidly and by now comprise millions of different ...
Ants and termites boost dryland wheat yields
2011-04-02
Ants and termites have a significant positive impact on crop yields in dryland agriculture, according to a paper published today in the journal Nature Communications by scientists at CSIRO and the University of Sydney.
"Ants and termites perform the same ecosystem service functions in dryland agriculture that earthworms perform in cooler and wetter areas, but the potential for ants and termites to provide these benefits has received little attention until now," said CSIRO's Dr Theo Evans.
"We already knew that the activities of ants and termites affect soil structure, ...
TGen and Scottsdale Healthcare researchers discover microRNA role in brain metastasis
2011-04-02
PHOENIX, Ariz. — March 31, 2011 — Conducting genetic profiles using microRNA can help doctors predict which lung cancer patients are likely to also develop brain metastasis (BM), according to a study published today by Scottsdale Healthcare and the Translational Genomics Research Institute (TGen).
The study identified microRNA-328 as a potential therapeutic target because of its association with the spread of cancer to the brain in patients with non-small cell lung cancer (NSCLC). NSCLC makes up 88 percent of the 222,000 annual U.S. cases of lung cancer, which is by far ...
Identifying the origin of the fly
2011-04-02
Some may think that the mosquito and the house fly are worlds apart when it comes to common ancestry but new research published this week by an international team of scientists puts them much closer together in evolutionary history.According to a paper published in the Proceedings of the National Academy of Sciences of the USA, the mosquito branched off the same evolutionary tree as the house fly around 220 million years ago.
Though just a few species of flies gain public attention as pests – namely: house flies, March flies and mosquitoes – there are 152,000 named species ...
First broad-scale maps of life on the sea-shelf
2011-04-02
Marine scientists from five research agencies have pooled their skills and resources to compile a directory of life on Australia's continental shelf.
They examined the shelf seascape during a three-year program of the Commonwealth Environment Research Facilities (CERF) Marine Biodiversity Hub.
Hub director, Professor Nic Bax of CSIRO and the University of Tasmania, says the program developed and applied a consistent, national approach to biodiversity mapping.
"The program compiled existing biological survey datasets, mapped 1868 square kilometres of seabed with multibeam ...