 |
|
Toward a quantum computer, one dot at a time
January 20, 2006Pitt researchers develop nanoscale semiconductor islands small enough to hold single electrons
Researchers at the University of Pittsburgh have developed a way to create semiconductor islands smaller than 10 nanometers in scale, known as quantum dots. The islands, made from germanium and placed on the surface of silicon with two-nanometer precision, are capable of confining single electrons.
"We believe this development moves us closer to our goal of constructing a quantum computer," said Jeremy Levy, Pitt professor of physics and astronomy and director of the Pittsburgh-based Center for Oxide-Semiconductor Materials for Quantum Computation. Levy and colleagues reported on the advance in a paper published in October 2005 in the journal Applied Physics Letters.
Quantum computers do not yet exist, but it is known that they can bypass all known encryption schemes used today on the Internet. Quantum computers also are capable of efficiently solving the most important equation in quantum physics: the Schrödinger equation, which describes the time-dependence of quantum mechanical systems. Hence, if quantum computers can be built, they likely will have as large an impact on technology as the transistor.
Electrons have a property known as "spin," which can take one of two directions-clockwise and counter-clockwise. Because of their quantum-mechanical nature, electrons can spin in both directions at once. That bizarre property allows the spin to be used as a "quantum bit" in a quantum computer. The ability to confine individual electrons, as opposed to "puddles" of electrons used in conventional computer technology, is essential for the working of a quantum computer.
The next step, said Levy, is to perform electronic and optical measurements on these materials to prove that there is indeed one electron on each quantum dot and to probe the coupling between the spins of neighbor electrons. "We can do that now because we have this control over the spacing and the size," he said.
The results achieved by Levy and colleagues are an example of "essentially nano" research, which involves manipulating properties at the smallest scales-from one to 20 nanometers.
Pitt has invested heavily in nanoscale research, beginning with the establishment of its Institute for NanoScience and Engineering (INSE), and continuing with the NanoScale Fabrication and Characterization Facility, which contains core technology such as electron-beam lithography, transmission electron microscopes, and a state-of-the-art cleanroom environment. The INSE is an integrated, multidisciplinary organization that brings coherence to the University's research efforts and resources in the fields of nanoscale science and engineering. For more information, visit www.nano.pitt.edu.
Other researchers on the study were John T. Yates Jr., R.K. Mellon Professor of Chemistry and Physics at Pitt; former Pitt chemistry graduate student Olivier Guise; Joachim Ahner of Pittsburgh-based Seagate Technology; and Venugopalan Vaithyanathan and Darrell G. Schlom of Pennsylvania State University.
University of Pittsburgh
Electrons have a property known as "spin," which can take one of two directions-clockwise and counter-clockwise. Because of their quantum-mechanical nature, electrons can spin in both directions at once. That bizarre property allows the spin to be used as a "quantum bit" in a quantum computer. The ability to confine individual electrons, as opposed to "puddles" of electrons used in conventional computer technology, is essential for the working of a quantum computer.
The next step, said Levy, is to perform electronic and optical measurements on these materials to prove that there is indeed one electron on each quantum dot and to probe the coupling between the spins of neighbor electrons. "We can do that now because we have this control over the spacing and the size," he said.
The results achieved by Levy and colleagues are an example of "essentially nano" research, which involves manipulating properties at the smallest scales-from one to 20 nanometers.
Pitt has invested heavily in nanoscale research, beginning with the establishment of its Institute for NanoScience and Engineering (INSE), and continuing with the NanoScale Fabrication and Characterization Facility, which contains core technology such as electron-beam lithography, transmission electron microscopes, and a state-of-the-art cleanroom environment. The INSE is an integrated, multidisciplinary organization that brings coherence to the University's research efforts and resources in the fields of nanoscale science and engineering. For more information, visit www.nano.pitt.edu.
Other researchers on the study were John T. Yates Jr., R.K. Mellon Professor of Chemistry and Physics at Pitt; former Pitt chemistry graduate student Olivier Guise; Joachim Ahner of Pittsburgh-based Seagate Technology; and Venugopalan Vaithyanathan and Darrell G. Schlom of Pennsylvania State University.
University of Pittsburgh
Quantum News and Current Quantum Events RSSExplosives go "green"
Certain explosives may soon get a little greener and a little more precise.
'Racetrack' for fast electrons in semiconductor structures
In order to realize the electrical units of voltage, resistance and current with highest accuracy quantum effects in nano-circuits are nowadays used. Important prerequisites are extremely pure semiconductor layers where high-mobile electrons move through the crystal without collision with residual impurities.
Scientists reveal effects of quantum 'traffic jam' in high-temperature superconductors
Scientists at the U.S. Department of Energy's Brookhaven National Laboratory, in collaboration with colleagues at Cornell University, Tokyo University, the University of California, Berkeley, and the University of Colorado, have uncovered the first experimental evidence for why the transition temperature of high-temperature superconductors -- the temperature at which these materials carry electrical current with no resistance -- cannot simply be elevated by increasing the electrons' binding energy.
Creating unconventional metals
The semiconductor silicon and the ferromagnet iron are the basis for much of mankind's technology, used in everything from computers to electric motors. In this week's issue of the journal Nature (August 21st) an international group of scientists, including academic and industrial researchers from the UK, USA and Lesotho, report that they have combined these elements with a small amount of another common metal, manganese, to create a new material which is neither a magnet nor an ordinary semiconductor.
Fast quantum computer building block created
The fastest quantum computer bit that exploits the main advantage of the qubit over the conventional bit has been demonstrated by researchers at University of Michigan, U.S. Naval Research Laboratory and the University of California at San Diego.
Light touch: Controlling the behavior of quantum dots
Researchers from the National Institute of Standards and Technology (NIST) and the Joint Quantum Institute (JQI), a collaborative center of the University of Maryland and NIST, have reported a new way to fine-tune the light coming from quantum dots by manipulating them with pairs of lasers.
True properties of carbon nanotubes measured
For more than 15 years, carbon nanotubes (CNTs) have been the flagship material of nanotechnology. Researchers have conceived applications for nanotubes ranging from microelectronic devices to cancer therapy. Their atomic structure should, in theory, give them mechanical and electrical properties far superior to most common materials.
Toward plastic spin transistors
University of Utah physicists successfully controlled an electrical current using the "spin" within electrons - a step toward building an organic "spin transistor": a plastic semiconductor switch for future ultrafast computers and electronics.
New theory for latest high-temperature superconductors
Physicists from Rice and Rutgers universities have published a new theory that explains some of the complex electronic and magnetic properties of iron "pnictides." In a series of startling discoveries this spring, pnictides were shown to superconduct at relatively high temperatures. The surprising discoveries created a great deal of excitement in the condensed matter physics community, which has been scrambling to better understand and document the unexpected results.
Strange molecule in the sky cleans acid rain, scientists discover
Researchers have discovered an unusual molecule that is essential to the atmosphere's ability to break down pollutants, especially the compounds that cause acid rain.
More Quantum News Articles
 | Quantum Wellness: A Practical and Spiritual Guide to Health and Happiness by Kathy Freston From the New York Times bestselling author comes the ultimate guide to complete well-being-an instructive book on how to reach our highest level of health and contentment through small, focused changes.Featuring a foreword by #1 New York Times bestselling author Dr. Mehmet C. Oz, Quantum Wellness will forever change the way readers approach healthy... |
 | The Black Hole War: My Battle with Stephen Hawking to Make the World Safe for Quantum Mechanics by Leonard Susskind What happens when something is sucked into a black hole? Does it disappear? Three decades ago, a young physicist named Stephen Hawking claimed it did-and in doing so put at risk everything we know about physics and the fundamental laws of the universe. Most scientists didn't recognize the import of Hawking's claims, but Leonard Susskind and Gerard t'Hooft realized the threat, and responded with a... |
 | Physics of the Impossible: A Scientific Exploration into the World of Phasers, Force Fields, Teleportation, and Time Travel by Michio Kaku A fascinating exploration of the science of the impossible—from death rays and force fields to invisibility cloaks—revealing to what extent such technologies might be achievable decades or millennia into the future.One hundred years ago, scientists would have said that lasers, televisions, and the atomic bomb were beyond the realm of physical possibility. In Physics of the Impossible,... |
 | Matrix Energetics: The Science and Art of Transformation by Richard Bartlett In 1997, Dr. Richard Bartlett experienced an event that would redirect the entire course of his life.He suddenly discovered that by lightly touching his clients while at the same time applying focused intent, he could restore them to a physically, mentally, and spiritually balanced state, instantly shifting misalignments that had plagued them for years. Most astonishing of all, he could teach... |
 | The Field Updated Ed: The Quest for the Secret Force of the Universe by Lynne Mctaggart Science has recently begun to prove what ancient myth and religion have always espoused: There may be such a thing as a life force. In this groundbreaking classic, investigative journalist Lynne McTaggart reveals a radical new paradigm—that the human mind and body are not separate from their environment but a packet of pulsating power constantly interacting with this vast energy sea,... |
 | The Spontaneous Healing of Belief: Shattering the Paradigm of False Limits by Gregg Braden What would it mean to discover that everything from the DNA of life, to the future of our world, is based upon a simple Reality Code—one that we can change and upgrade by choice? New revelations in physics and biology suggest that we’re about to find out! A growing body of scientific evidence suggests that our universe works like a Consciousness Computer. Rather than the number codes of... |
 | The Intention Experiment: Using Your Thoughts to Change Your Life and the World by Lynne McTaggart The book you hold in your hands is revolutionary, a groundbreaking exploration of the science of intention.Drawing on the findings of leading scientists from around the world, The Intention Experiment demonstrates that thought is a thing that affects other things. It is also the first book to invite you, the reader, to take an active part in its original research.Using cutting-edge research... |
 | A Brief History of Time by Stephen Hawking Stephen Hawking, one of the most brilliant theoretical physicists in history, wrote the modern classic A Brief History of Time to help nonscientists understand the questions being asked by scientists today: Where did the universe come from? How and why did it begin? Will it come to an end, and if so, how? Hawking attempts to reveal these questions (and where we're looking for answers) using a... |
 | Introduction to Quantum Mechanics (2nd Edition) by David J. Griffiths This book first teaches learners how to do quantum mechanics, and then provides them with a more insightful discussion of what it means. Fundamental principles are covered, quantum theory presented, and special techniques developed for attacking realistic problems. The bookoverage organizes topics under basic theory, and assembles an arsenal of approximation schemes with illustrative... |
 | The Holographic Universe by Michael Talbot Today nearly everyone is familiar with holograms, three-dimensional images projected into space with the aid of a laser. Now, two of the world's most eminent thinkers -- University of London physicists David Bohm, a former protege of Einstein's and one of the world's most respected quantum physicists, and Stanford neurophysiologist Karl Pribram, one of the architects of our modern understanding... |
| © 2008 BrightSurf.com |