Navigation Links
Evidence of macroscopic quantum tunneling detected in nanowires
Date:5/27/2009

CHAMPAIGN, Ill. A team of researchers at the University of Illinois has demonstrated that, counter to classical Newtonian mechanics, an entire collection of superconducting electrons in an ultrathin superconducting wire is able to "tunnel" as a pack from a state with a higher electrical current to one with a notably lower current, providing more evidence of the phenomenon of macroscopic quantum tunneling.

Physics professors Alexey Bezryadin and Paul Goldbart led the team, with graduate student Mitrabhanu Sahu performing the bulk of the measurements. Their research was published on the Web site of the journal Nature Physics on May 17.

Quantum tunneling is the capability of a particle to inhabit regions of space that would normally be off-limits according to classical mechanics. This research observes a process called a quantum phase slip, whereby packs of roughly 100,000 electrons tunnel together from higher electrical current states to lower ones. The energy locked in the motion of the electrons as they phase slip is dissipated as heat, causing the nanowires to switch from a superconducting state to a more highly resistive one.

It's through this switching of states that allows the tunneling of the phase slip to be observed, the researchers say.

Goldbart, who is also a researcher at the university's Frederick Seitz Materials Research Laboratory, describes a quantum phase slip as a phenomenon that allows the spatially extended structure of superconductivity "to undergo a kind of quantum mechanical rip or tear, one where the entire extended behavior of the superconductivity tunnels its way through a classically forbidden set of configurations."

"Semiconductors, insulators and metals all hinge upon the ability of particles to make it through classically forbidden regions, despite apparently having negative kinetic energy there, as quantum physics allows," Goldbart said.

In Newton's world, according to Goldbart, particles would be reflected from such regions.

Although quantum mechanics governs the realm of atoms and molecules and smaller, quantum phenomena sometimes "leak up" to macroscopic scales, he said.

The ultrathin superconducting nanowires fabricated and measured by Sahu and his co-researchers are about 2,000 times finer than a single strand of human hair, which is still "a substantially larger scale than where one typically expects to observe quantum tunneling," Bezryadin said.

According to Bezryadin, who is also a researcher at the Beckman Institute and the Illinois Micro and Nanotechnology Laboratory, it has long been established that single electrons can tunnel, but scant evidence has existed until now for the group tunneling of a large ensemble of superconducting electrons confined in a thin wire.

"Observing switching events in superconducting nanowires at high-bias currents provides strong evidence for quantum phase slips," Bezryadin said. "Our experiments provide further evidence that the laws of quantum mechanics continue to govern large systems, composed of many thousands of electrons, acting as a single entity."

Both researchers believe that the practical implication of knowledge gleaned from research into quantum tunneling could have applications in the field of quantum computing.

"If we learn how to evade the factors that currently suppress quantum superpositions at the macro-scale," Bezryadin said, "we would be better positioned to construct quantum bits for quantum computers, which could perform tasks with an enormous increase in speed and security."


'/>"/>

Contact: Phil Ciciora
pciciora@illinois.edu
217-333-2177
University of Illinois at Urbana-Champaign
Source:Eurekalert  

Related biology technology :

1. CPM Resource Center and The Shams Group Partner To Help Hospitals Integrate Evidence-Based Clinical Content Into Information Systems
2. MichBio Leader Cites New Senate Biosciences Task Force and House Subcommittee as Evidence of States Growing Awareness of Industrys Economic Importance
3. ULURU to Present Clinical Evidence and Advanced Research on Altrazeal at the Society for Advance Wound Care Conference for 2009
4. Agendia Publishes Direct Evidence That MammaPrint Predicts Benefit of Chemotherapy in Breast Cancer
5. Evidence of Ancient Hot Springs on Mars Detailed in Astrobiology Journal
6. Cancer Clinics of Excellence (CCE) Releases 62nd Evidence-Based Treatment Protocol
7. The Lancets New Online Medical Journal Helps Clinicians and Medical Researchers Find Practice-Changing Evidence Quickly and Easily
8. More Evidence Published That Epidemics of Childhood Obesity, Type 2 Diabetes and Metabolic Syndrome are Linked to Immunization
9. Kaiser Permanente Study Shows Newer, Stronger Evidence That Caffeine During Pregnancy Increases Miscarriage Risk
10. Revolutionary Genomics Research Group Opens Boston Office; Provides DNA Evidence in Workers Comp Cases
11. PDL BioPharma Announces Internal CEO Investigation Found No Credible Evidence of Improper Personal Conduct or Breach of Fiduciary Duty
Post Your Comments:
*Name:
*Comment:
*Email:
Related Image:
Evidence of macroscopic quantum tunneling detected in nanowires
(Date:4/21/2017)... ... April 21, 2017 , ... The University of ... round funding to three startups through the UConn Innovation Fund. The $1.5 million ... startups affiliated with UConn. , The UConn Innovation Fund provides investments of up ...
(Date:4/21/2017)... ... , ... Frederick Innovative Technology Center, Inc. (FITCI), a business ... earned a $77,518 grant from the Rural Maryland Council (RMC) to support refurbishment ... first incubator. A non-profit corporation, FITCI is a public-private partnership of the governments ...
(Date:4/20/2017)... BARBARA, CALIFORNIA (PRWEB) , ... April 20, 2017 , ... ... optimization firm for the life sciences and healthcare industries, is pleased to announce ... the new established USDM subsidiary “USDM Europe GmbH” based in Germany. , Braemer ...
(Date:4/20/2017)... Woburn, MA (PRWEB) , ... April 20, 2017 ... ... high brightness light sources for advanced technology applications, announced today that Chief Executive ... Board (NAAB). , SEMI is the global industry association connecting the ...
Breaking Biology Technology:
(Date:3/22/2017)... , March 21, 2017 Vigilant Solutions ... serving law enforcement agencies, announced today the appointment of ... director of public safety business development. Mr. ... enforcement experience, including a focus on the aviation transportation ... most recent position, Mr. Sheridan served as the Aviation ...
(Date:3/20/2017)... , March 20, 2017 PMD Healthcare announces ... spirometer and Wellness Management System (WMS), a remote, real-time ... in 2010, PMD Healthcare is a Medical Device, Digital ... mission dedicated to creating innovative solutions that empower people ... that intent focus, PMD developed the first ever personal ...
(Date:3/13/2017)... -- Future of security: Biometric Face Matching software  ... ... Face Matching enables to match face pictures against each other or against large ... Identification Systems) ... is the fastest software for biometric Face Matching on the market. The speed ...
Breaking Biology News(10 mins):