(Press-News.org) Contact information: Robert Perkins
perkinsr@usc.edu
213-740-9226
University of Southern California
Scientists use 'voting' and 'penalties' to overcome errors in quantum optimization
Study demonstrates that when the D-Wave quantum processor is led astray by noise, error correction can ensure that it functions as intended
Seeking a solution to decoherence—the "noise" that prevents quantum processors from functioning properly—scientists at USC have developed a strategy of linking quantum bits together into voting blocks, a strategy that significantly boosts their accuracy.
In a paper published today in Nature Communications, the team found that their method results in at least a five-fold increase in the probability of reaching the correct answer when the processor solves the largest problems tested by the researcher, involving hundreds of qubits.
The team, led by Daniel Lidar—director of the USC-Lockheed Martin Quantum Computing Center at the USC Viterbi School of Engineering—ran their tests on the 512-quantum-bit D-Wave Two processor. The D-Wave Two is among the first commercially available quantum processors, a device so advanced that there are only two in use outside the Canadian company where they were built: The first one went to USC and Lockheed Martin, and the second to NASA and Google.
"We have demonstrated that our quantum annealing correction strategy significantly improves the success probability of the D-Wave Two processor on the benchmark problem of antiferromagnetic chains, and are planning to next use it on computationally hard problems," Lidar said. His team includes graduate student Kristen Pudenz and postdoctoral fellow Tameem Albash.
Lidar added that all quantum information processors are expected to be highly susceptible to decoherence, so that error correction is viewed as an essential and inescapable part of quantum computing.
Quantum processors encode data in qubits, which have the capability of representing the two digits of one and zero at the same time – as opposed to traditional bits, which can encode distinctly either a one or a zero. This property, called superposition, along with the ability of quantum states to "interfere" (cancel or reinforce each other like waves in a pond) and "tunnel" through energy barriers, is what may one day allow quantum processors ultimately perform optimization calculations much faster than traditional processors.
Decoherence knocks qubits out of superposition, forcing them to behave as traditional bits, and robbing them of their edge over traditional processors.
Pudenz, Albash and Lidar developed and tested a strategy of grouping three qubits together into larger blocks of encoded qubits that can be decoded by a "majority vote." This way, if decoherence affects one of the qubits and causes it to "flip" to the incorrect value, the other two qubits in the block ensure that the data is still correctly encoded and can be correctly decoded by out-voting the errant qubit.
These voting blocks of qubits are then magnetically tied to a fourth qubit in such a way that if any one "flips" then all four must flip. In effect, it makes the whole block of four so massive that it's difficult for one lonely qubit acting under the influence of decoherence to throw a wrench in the works.
###
This research was funded by the Army Research Office, the Lockheed Martin Corporation, and the National Science Foundation.
Read the study at: http://www.nature.com/ncomms/2014/140206/ncomms4243/full/ncomms4243.html
Scientists use 'voting' and 'penalties' to overcome errors in quantum optimization
Study demonstrates that when the D-Wave quantum processor is led astray by noise, error correction can ensure that it functions as intended
2014-02-06
ELSE PRESS RELEASES FROM THIS DATE:
Ballistic transport in graphene suggests new type of electronic device
2014-02-06
Using electrons more like photons could provide the foundation for a new type of electronic device that would capitalize on the ability of graphene to carry electrons with almost no resistance ...
Amputee feels in real-time with bionic hand
2014-02-06
PUBLIC RELEASE DATE: 5-Feb-2014
[
| E-mail
]
var addthis_pub="eurekalert"; var addthis_options = "favorites, delicious, digg, facebook, twitter, google, newsvine, reddit, slashdot, stumbleupon, buzz, more"
Share
Contact: Hillary Sanctuary
hillary.sanctuary@epfl.ch
41-216-937-022
Ecole Polytechnique Fédérale de Lausanne
Amputee feels in real-time with bionic hand
Dennis Aabo Sorensen is the first amputee in the world to feel sensory rich information -- in real-time -- with a prosthetic hand wired to nerves in his upper arm; Sorensen could grasp objects ...
Inducing climate-smart global supply networks: Nature Commentary
2014-02-06
In a Nature Commentary he proposes a community effort to collect economic data on the new website zeean.net. The aim is to better understand economic flows and to thereby ...
New approach prevents thrombosis without increasing the risk of bleeding
2014-02-06
In collaboration with an international team, researchers at Karolinska Institutet in Sweden have developed an antibody, 3F7, which blocks a protein that is active in the coagulation system factor ...
Some receive unnecessary prioritization for liver transplantation, says Penn Medicine study
2014-02-06
(PHILADELPHIA) – Patients waiting for liver transplants ...
New analysis of endometriosis could help diagnoses, treatments
2014-02-06
CAMBRIDGE, MA -- Endometriosis, the invasive displacement of uterine tissue into surrounding organs, affects at least 10 percent of women. The disease, which is often misdiagnosed, can cause ...
Female mice prefer unfamiliar male songs
2014-02-06
Female mice prefer songs of mice that are different from their parents when selecting a mate, according to a study published February 5, 2014 in PLOS ONE by Akari Asaba from the Azabu University, ...
Mass extinction may not cause all organisms to 'shrink'
2014-02-06
The sizes of organisms following mass extinction events may vary more than previously thought, which may be inconsistent with the predictions of the so-called ...
Tree roots in the mountains 'acted like a thermostat' for millions of years
2014-02-06
For the first time, scientists have discovered how tree roots in the mountains may play an important role in controlling long-term global temperatures. Researchers from Oxford ...
New stem cell research removes reliance on human and animal cells
2014-02-06
A new study, published today in the journal Applied Materials & Interfaces, has found a new method for growing human embryonic stem cells, that doesn't rely on supporting human or animal cells.
Traditionally, ...
LAST 30 PRESS RELEASES:
Decoding the secrets of ‘chemo brain’
‘Far from negligible’: New Australian fossil fuel site will have major impact on people and the planet
UK heatwaves overwhelm natural ecological safeguards to increase wildfire risk
Key ExoMars Rover part ships from Aberystwyth
90% of Science Is Lost: Frontiers’ revolutionary AI-powered service transforms data sharing to deliver breakthroughs faster
Skin symptoms may forewarn mental health risks
Brain test predicts ability to achieve orgasm – but only in patients taking antidepressants
‘New reality’ as world reaches first climate tipping point
Non-English primary language may raise risk of delirium after surgery, study finds
Children fast from clear liquids much longer before surgery than guidelines recommend, large study shows
Food insecurity, loneliness can increase the risk of developing chronic pain after surgery
Cesarean delivery linked to higher risk of pain and sleep problems after childbirth
New global burden of disease study: Mortality declines, youth deaths rise, widening health inequities
Chemobiological platform enables renewable conversion of sugars into core aromatic hydrocarbons of petroleum
Individualized perioperative blood pressure management in patients undergoing major abdominal surgery
Proactive vs reactive treatment of hypotension during surgery
Different types of depression linked to different cardiometabolic diseases
Ketogenic diet may protect against stress experienced in the womb
Adults 65 years and older not immune to the opioid epidemic, new study finds
Artificial intelligence emerging as powerful patient safety tool in pediatric anesthesia
Mother’s ZIP code, lack of access to prenatal care can negatively impact baby’s health at birth, new studies show
American Society of Anesthesiologists honors John M. Zerwas, M.D., FASA, with Distinguished Service Award
A centimeter-scale quadruped piezoelectric robot with high integration and strong robustness
Study confirms that people with ADHD can be more creative. The reason may be that they let their mind wander
Research gives insight into effect of neurodegenerative diseases on speech rhythm
Biochar and plants join forces to clean up polluted soils and boost ecosystem recovery
Salk scientist Joseph Ecker awarded McClintock Prize for Plant Genetics and Genome Studies
ADHD: Women are diagnosed five years later than men, despite symptoms appearing at the same age.
Power plants may emit more pollution during government shutdowns
Increasing pressures for conformity de-skilling and demotivating teachers, study warns
[Press-News.org] Scientists use 'voting' and 'penalties' to overcome errors in quantum optimizationStudy demonstrates that when the D-Wave quantum processor is led astray by noise, error correction can ensure that it functions as intended