Quantum information motion control is now improved
Model simulates closer control over the transport of information-carrying electrons
2012-04-04
(Press-News.org) Physicists have recently devised a new method for handling the effect of the interplay between vibrations and electrons on electronic transport. Their paper is about to be published in EPJ B¹. This study, led by scientists from Zhejiang University, Hangzhou, China, and the Centre for Computational Science and Engineering at the National University of Singapore, could have implications for quantum computers due to improvements in the transport of discrete amounts of information, known as qubits, that are encoded in electrons.
The authors created an electron transport model to assess electrons' current fluctuations when they are subjected to quantized modes of vibration, also known as phonons. In the model, phonons are induced by a nanomechanical resonator. To better monitor electron transport, it is coupled to a system that was chosen for its ability to confine one or several electrons, called double quantum dot (DQD). Unlike previous studies, this work imposed arbitrary strong coupling regimes between electrons in the DQD and the phonons produced by the resonator.
The authors successfully controlled the excitations of the phonons without impacting the transport of quantum information. To do so, they decoupled the electron-phonon interaction by the so-called coherent phonon states method, which is based on reaching resonance modes of phonons. They have shown that when the energy excess between the two quantum dots of the DQD system is sufficient to create an integer number of phonons, electrons can reach resonance and tunnel from one quantum dot to the other. In strong electron-phonon coupling regimes, multi-phonon excitations can thus enhance the electron transport.
As the electron-phonon coupling becomes even stronger, the phenomenon of phonon scattering represses electron transport and confines the electrons. The fluctuations of electron current could therefore be controlled by tuning the electron-phonon coupling, which makes it a good quantum switch to control the transport of information in quantum computers.
INFORMATION:
References:
1. Wang C., Ren J., Li B., Chen Q-H. (2012), Quantum transport of double quantum dots coupled to an oscillator in arbitrary strong coupling regime, European Physical Journal B (EPJ B). DOI 10.1140/epjb/e2012-30027-1
2. For more information, please visit www.epj.org.
The full-text article is available to journalists on request.
END
ELSE PRESS RELEASES FROM THIS DATE:
2012-04-04
A current study shows that the risk for coronary heart disease and stroke increases by almost thirty per cent in a person whose partner has cancer. The cause is probably the negative stress to which the cancer patient's relative is exposed.
We know that the relatives of chronically ill patients, especially cancer patients, have an increased risk of mental illness and depression. Previous studies have reported that mental stress and depression affect the nervous system, blood pressure and inflammation, which in turn can increase the risk of developing coronary heart disease ...
2012-04-04
Philadelphia, PA, April 3, 2012 – Depressed individuals with a tendency to ruminate on negative thoughts, i.e. to repeatedly think about particular negative thoughts or memories, show different patterns of brain network activation compared to healthy individuals, report scientists of a new study in Biological Psychiatry.
The risk for depression is increased in individuals with a tendency towards negative ruminations, but patterns of autobiographic memory also may be predictive of depression.
When asked to recall specific events, some individuals have a tendency to ...
2012-04-04
Alexandria, VA – Tornadoes are notoriously difficult to forecast, with often deadly results: In 2011, tornadoes in the U.S. killed more than 550 people, a higher death toll than in the past 10 years combined. Now a new study on short-term climate trends offers a fresh approach to tornado forecasting that may give people in tornado-prone regions more warning that twisters may soon be descending.
By sorting through average atmospheric conditions in tornado-prone regions, Michael Tippet, a climate scientist at Columbia University, may have found a way to predict tornado ...
2012-04-04
TAMPA, Fla. (April 3, 2012) – Researchers at Moffitt Cancer Center have carried out a study to validate the utility of new tumor classification systems for staging and predicting relapse-free survival for patients with neuroendocrine tumors (NETs) and who may be candidates for surgery.
The results of their study were published in a recent issue of the Annals of Surgery.
Neuroendocrine tumors, which form in the islet cells of the pancreas, are a relatively rare form of cancer, accounting for about 3 percent of all pancreatic malignancies. NETs that have not spread ...
2012-04-04
(Boston) - Anurag Singh, PhD, assistant professor in the Department of Pharmacology and Experimental Therapeutics at Boston University School of Medicine has been invited to present his recent work on targeted therapeutics for colon cancer at the American Association of Cancer Research Annual Meeting in Chicago, IL. Singh's seminar, scheduled for Tuesday April 3rd, will be featured in the "Late-Breaking Abstracts Mini-Symposium". This highlights recent and provocative groundbreaking research in cancer biology.
Over one million cases of colon cancer are diagnosed worldwide ...
2012-04-04
People who are excluded by others online, such as on Facebook, may feel just as bad as if they had been excluded in person, according to researchers at Penn State and Misericordia University.
"If you've ever felt bad about being 'ignored' on Facebook you're not alone," said Joshua Smyth, professor of biobehavioral health and of medicine at Penn State. "Facebook -- with its approximately 800 million users -- serves as a place to forge social connections; however, it is often a way to exclude others without the awkwardness of a face-to-face interaction. Most people would ...
2012-04-04
Higher-spending hospitals do have better outcomes for their emergency patients, including fewer deaths, according to a Vanderbilt study released as a working paper through the National Bureau of Economic Research.
Vanderbilt's John Graves, Ph.D., assistant professor of Preventive Medicine, along with colleagues from the Massachusetts Institute of Technology and Cornell University, examined Medicare ambulance and hospital data from 2002-2008, finding that higher-cost hospitals have significantly lower one-year mortality rates compared to lower-cost hospitals.
"At ...
2012-04-04
Dr. Steve Hahn, Acworth prosthodontist, and his staff are pleased to announce the pending opening of a new location in Midtown, Atlanta. The new location will give Dr. Hahn and his associates access to a whole new group of patients.
Roughly 30 miles from the current Acworth location, the Midtown location will be able to bring dental services to a large population center in the heart of Atlanta. For patients of the Acworth dentist who may live closer to Midtown or are employed there, the new location offers a new level of convenience.
"We are all tremendously ...
2012-04-04
CHICAGO, IL – April 3, 2012 – The brains of people with anorexia and obesity are wired differently, according to new research. Neuroscientists for the first time have found that how our brains respond to food differs across a spectrum of eating behaviors – from extreme overeating to food deprivation. This study is one of several new approaches to help better understand and ultimately treat eating disorders and obesity.
Eating disorders have the highest mortality rate of any mental illness. And more than two-thirds of the U.S. population are overweight or obese – a health ...
2012-04-04
Scientists have long believed that vitamin D, which is naturally absorbed from sunlight, has an important role in the functioning of the body's autoimmune system. Now Prof. Howard Amital of Tel Aviv University's Sackler Faculty of Medicine and Sheba Medical Center has discovered that the vitamin may also affect the outcomes of patients in intensive care.
In a six-month study, Prof. Amital and his colleagues found that patients who had a vitamin D deficiency lived an average of 8.9 days less than those who were found to have sufficient vitamin D. Vitamin D levels also ...
LAST 30 PRESS RELEASES:
[Press-News.org] Quantum information motion control is now improved
Model simulates closer control over the transport of information-carrying electrons
