Home > Press > When nanotechnology meets quantum physics in one dimension: New experiment supports long-predicted "Luttinger liquid" model
Abstract:
How would electrons behave if confined to a wire so slender they could pass through it only in single-file?
The question has intrigued scientists for more than half a century. In 1950, Japanese Nobel Prize winner Sin-Itiro Tomonaga, followed by American physicist Joaquin Mazdak Luttinger in 1963, came up with a mathematical model showing that the effects of one particle on all others in a one-dimensional line would be much greater than in two- or three-dimensional spaces. Among quantum physicists, this model came to be known as the "Luttinger liquid" state.
Until very recently, however, there had been only a few successful attempts to test the model in devices similar to those in computers, because of the engineering complexity involved. Now, scientists from McGill University and Sandia National Laboratories have succeeded in conducting a new experiment that supports the existence of the long-sought-after Luttinger liquid state. Their findings, published in the Jan. 23 issue of Science Express, validate important predictions of the Luttinger liquid model.
The experiment was led by McGill PhD student Dominique Laroche under the supervision of Professor Guillaume Gervais of McGill's Department of Physics and Dr. Michael Lilly of Sandia National Laboratories in Albuquerque, N.M. The new study follows on the team's discovery in 2011 of a way to engineer one of the world's smallest electronic circuits, formed by two wires separated by only about 15 nanometers, or roughly 150 atoms.
What does one-dimensional quantum physics involve? Gervais explains it this way: "Imagine that you are driving on a highway and the traffic is not too dense. If a car stops in front of you, you can get around it by passing to the left or right. That's two-dimensional physics. But if you enter a tunnel with a single lane and a car stops, all the other cars behind it must slam on the brakes. That's the essence of the Luttinger liquid effect. The way electrons behave in the Luttinger state is entirely different because they all become coupled to one another."
To scientists, "what is so fascinating and elegant about quantum physics in one dimension is that the solutions are mathematically exact," Gervais adds. "In most other cases, the solutions are only approximate."
Making a device with the correct parameters to conduct the experiment was no simple task, however, despite the team's 2011 discovery of a way to do so.. It took years of trial, and more than 250 faulty devices - each of which required 29 processing steps - before Laroche's painstaking efforts succeeded in producing functional devices yielding reliable data. "So many things could go wrong during the fabrication process that troubleshooting the failed devices felt like educated guesswork at times," explains Laroche. "Adding in the inherent failure rate compounded at each processing step made the fabrication of these devices extremely challenging."
In particular, the experiment measures the effect that a very small electrical current in one of the wires has on a nearby wire. This can be viewed as the "friction" between the two circuits, and the experiment shows that this friction increases as the circuits are cooled to extremely low temperatures. This effect is a strong prediction of Luttinger liquid theory.
The experiments were conducted both at McGill University and at the Center for Integrated Nanotechnologies, a U.S. Department of Energy, Office of Basic Energy Sciences user facility operated by Sandia National Laboratories.
"It took a very long time to make these devices," said Lilly. "It's not impossible to do in other labs, but Sandia has crystal-growing capabilities, a microfabrication facility, and support for fundamental research from DOE's office of Basic Energy Sciences (BES), and we're very interested in understanding the fundamental ideas that drive the behavior of very small systems."
The findings could lead to practical applications in electronics and other fields. While it's difficult at this stage to predict what those might be, "the same was true in the case of the laser when it was invented," Gervais notes. "Nanotechnologies are already helping us in medicine, electronics and engineering - and this work shows that they can help us get to the bottom of a long-standing question in quantum physics."
The research was supported by the Division of Materials Sciences and Engineering, Office of Basic Energy Sciences, U.S. Department of Energy; the Natural Sciences and Engineering Research Council of Canada (NSERC); the Canadian Institute for Advanced Research (CIFAR), and the Fonds québécois de la recherche sur la nature et les technologies (FQRNT).
####
About McGill University
Founded in Montreal, Que., in 1821, is Canada’s leading post-secondary institution. It has two campuses, 11 faculties, 10 professional schools, 300 programs of study and more than 35,000 students. McGill attracts students from more than 150 countries around the world. Almost half of McGill students claim a first language other than English – including 6,000 francophones – with more than 6,800 international students making up almost 20 per cent of the student body.
For more information, please click here
Contacts:
Chris Chipello
Media Relations
McGill University
514-398-4201
Prof. Guillaume Gervais
Department of Physics
McGill University
Copyright © AlphaGalileo
If you have a comment, please Contact us.Issuers of news releases, not 7th Wave, Inc. or Nanotechnology Now, are solely responsible for the accuracy of the content.
Related Links |
Full bibliographic information
Related News Press |
Physics
Simulating magnetization in a Heisenberg quantum spin chain April 5th, 2024
News and information
Simulating magnetization in a Heisenberg quantum spin chain April 5th, 2024
NRL charters Navy’s quantum inertial navigation path to reduce drift April 5th, 2024
Discovery points path to flash-like memory for storing qubits: Rice find could hasten development of nonvolatile quantum memory April 5th, 2024
Govt.-Legislation/Regulation/Funding/Policy
NRL charters Navy’s quantum inertial navigation path to reduce drift April 5th, 2024
Discovery points path to flash-like memory for storing qubits: Rice find could hasten development of nonvolatile quantum memory April 5th, 2024
Chemical reactions can scramble quantum information as well as black holes April 5th, 2024
Chip Technology
Discovery points path to flash-like memory for storing qubits: Rice find could hasten development of nonvolatile quantum memory April 5th, 2024
Utilizing palladium for addressing contact issues of buried oxide thin film transistors April 5th, 2024
HKUST researchers develop new integration technique for efficient coupling of III-V and silicon February 16th, 2024
Discoveries
Chemical reactions can scramble quantum information as well as black holes April 5th, 2024
New micromaterial releases nanoparticles that selectively destroy cancer cells April 5th, 2024
Utilizing palladium for addressing contact issues of buried oxide thin film transistors April 5th, 2024
Announcements
NRL charters Navy’s quantum inertial navigation path to reduce drift April 5th, 2024
Discovery points path to flash-like memory for storing qubits: Rice find could hasten development of nonvolatile quantum memory April 5th, 2024
Interviews/Book Reviews/Essays/Reports/Podcasts/Journals/White papers/Posters
Simulating magnetization in a Heisenberg quantum spin chain April 5th, 2024
Discovery points path to flash-like memory for storing qubits: Rice find could hasten development of nonvolatile quantum memory April 5th, 2024
Research partnerships
Discovery points path to flash-like memory for storing qubits: Rice find could hasten development of nonvolatile quantum memory April 5th, 2024
Researchers’ approach may protect quantum computers from attacks March 8th, 2024
'Sudden death' of quantum fluctuations defies current theories of superconductivity: Study challenges the conventional wisdom of superconducting quantum transitions January 12th, 2024
Quantum nanoscience
Simulating magnetization in a Heisenberg quantum spin chain April 5th, 2024
Optically trapped quantum droplets of light can bind together to form macroscopic complexes March 8th, 2024
Bridging light and electrons January 12th, 2024
'Sudden death' of quantum fluctuations defies current theories of superconductivity: Study challenges the conventional wisdom of superconducting quantum transitions January 12th, 2024
The latest news from around the world, FREE | ||
Premium Products | ||
Only the news you want to read!
Learn More |
||
Full-service, expert consulting
Learn More |
||