(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:
Team discovers electrochemical method for highly selective single-carbon insertion in aromatic rings
What cats may teach us about Long COVID
Millions denied life-saving surgery as global targets missed – study
Record-breaking human imaging project crosses the finish line: 100,000 volunteers provide science with most detailed look inside the body
Bio detection dogs successfully detect Parkinson’s disease by odor, study finds
Insomnia could be key to lower life satisfaction in adults with ADHD traits, study finds
Study discusses how to mitigate damage from gunshot injuries to the brain in children and young adults
New research challenges animal dietary classifications in Yellowstone National Park
Parenthood not lessening loss for widowed people, 25 years of interviews suggest
UC Irvine astronomers discover scores of exoplanets may be larger than realized
Theory for aerosol droplets from contaminated bubbles bursting gives insight into spread of pollution, microplastics, infectious disease
AI-powered mobile retina tracker screens for diabetic eye disease with 99% accuracy
Implantable cell therapy has potential to restore adrenal function and treat primary adrenal insufficiency
Obesity and type 2 diabetes in teen years can impair bone health
Study finds strong link between acromegaly and increased cancer risk
Vapes more effective for smoking cessation than nicotine gum and lozenges
Aluminum exposure from childhood vaccines not linked to increased risk of autoimmune, allergic, or neurodevelopmental disorders
Smarter tools for policymakers: Notre Dame researchers target urban carbon emissions, building by building
Here’s how we help an iconic California fish survive the gauntlet of today’s highly modified waterways
New technique can dramatically improve laser linewidth
Forest trees and microbes choreograph their hunt for a ‘balanced diet’ under elevated CO2
Beyond health: The political effects of infectious disease outbreaks
For tastier and hardier citrus, researchers built a tool for probing plant metabolism
Stay hydrated: New sensor knows when you need a drink
Quantum internet meets space-time in this new ingenious idea
Soil erosion in mountain environments accelerated by agro-pastoral activities for 3,800 years
Optogenetic platform illuminates new antiviral strategies
A new theory explaining oscillations in tunnel magnetoresistance (TMR)
Early antibiotics alter immune function in infants
With the second grant to therapy
[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