Can We Build a Large-Scale Quantum Computer Using Semiconductor Materials?

MRS Bulletin ◽  
2005 ◽  
Vol 30 (2) ◽  
pp. 105-110 ◽  
Author(s):  
B. E. Kane
Keyword(s):  
Quantum Computing ◽  
San Francisco ◽  
Large Scale ◽  
Quantum Computer ◽  
Research Society ◽  
University Of Maryland ◽  
The Road ◽  
Materials Research ◽  
The One ◽  
Conventional Computer

AbstractThe following article is based on the Symposium X presentation given by Bruce E. Kane (University of Maryland) at the 2004 Materials Research Society Spring Meeting in San Francisco. Quantum computing has the potential to revolutionize our ability to solve certain classes of difficult problems. A quantum computer is able to manipulate individual two-level quantum states (“qubits”) in the same way that a conventional computer processes binary ones and zeroes. Here, Kane discusses some of the most promising proposals for quantum computing, in which the qubit is associated with single-electron spins in semiconductors. While current research is focused on devices at the one- and two-qubit level, there is hope that cross-fertilization with advancing conventional computer technology will enable the eventual development of a large-scale (thousands of qubits) semiconductor quantum computer.The author focuses on materials issues that will need to be surmounted if large-scale quantum computing is to be realizable. He argues in particular that inherent fluctuations in doped semiconductors will severely limit scaling and that scalable quantum computing in semiconductors may only be possible at the end of the road of Moore's law scaling, when devices are engineered and fabricated at the atomic level.

Efficient reversible quantum design of sig-magnitude to two's complement converters

2020 ◽  
Vol 20 (9&10) ◽  
pp. 747-765
Author(s):  
F. Orts ◽  
G. Ortega ◽  
E.M. E.M. Garzon
Keyword(s):  
Quantum Computing ◽  
Scientific Community ◽  
Quantum Computer ◽  
Fault Tolerant ◽  
State Of The Art ◽  
The Other ◽  
Quantum Computers ◽  
Binary Number ◽  
Quantum Cost ◽  
The One

Despite the great interest that the scientific community has in quantum computing, the scarcity and high cost of resources prevent to advance in this field. Specifically, qubits are very expensive to build, causing the few available quantum computers are tremendously limited in their number of qubits and delaying their progress. This work presents new reversible circuits that optimize the necessary resources for the conversion of a sign binary number into two's complement of N digits. The benefits of our work are two: on the one hand, the proposed two's complement converters are fault tolerant circuits and also are more efficient in terms of resources (essentially, quantum cost, number of qubits, and T-count) than the described in the literature. On the other hand, valuable information about available converters and, what is more, quantum adders, is summarized in tables for interested researchers. The converters have been measured using robust metrics and have been compared with the state-of-the-art circuits. The code to build them in a real quantum computer is given.

The Digital Evolution

MRS Bulletin ◽  
2006 ◽  
Vol 31 (11) ◽  
pp. 906-913 ◽  
Author(s):  
Craig R. Barrett
Keyword(s):  
Research And Development ◽  
San Francisco ◽  
Global Economy ◽  
Industrial Revolution ◽  
New Technologies ◽  
Research Society ◽  
Digital Evolution ◽  
Modern Life ◽  
The World ◽  
Materials Research

AbstractThe following article is an edited transcript based on the plenary address given by Craig R. Barrett, chair of the board of Intel Corp., on April 19, 2006, at the 2006 Materials Research Society Spring Meeting in San Francisco. Since before the industrial revolution, technology has changed lives, opportunities, and economies. Similarly, the digital evolution has touched nearly every aspect of modern life and is reshaping economies around the world. As more and more of the world's people engage in the digital economy, both competition and opportunities will grow. Competitiveness in the global economy will be determined by how people and nations position themselves in the digital evolution. What lies ahead for us in the next 10 years? What new technologies will alter the technology landscape? What are the opportunities going forward, and how do we prepare? How can materials research and development help us to move forward faster?

The Intersection of Biology and Materials Science

MRS Bulletin ◽  
2006 ◽  
Vol 31 (1) ◽  
pp. 19-27 ◽  
Author(s):  
George M. Whitesides ◽  
Amy P. Wong
Keyword(s):  
San Francisco ◽  
Materials Science ◽  
Research Society ◽  
Harvard University ◽  
Major Focus ◽  
Spring Meeting ◽  
Materials Research

AbstractThis article is based on the plenary address given by George M. Whitesides of Harvard University on March 30, 2005, at the Materials Research Society Spring Meeting in San Francisco. Materials science and biomedicine are arguably two of the most exciting fields in science today. Research at the border between them will inevitably be a major focus, and the applications of materials science to problems in biomedicine—that is, biomaterials science—will bud into an important new branch of materials science. Accelerating the growth of this area requires an understanding of two very different fields, and being both thoughtful and entrepreneurial in considering “Why?” “How?” and “Where?” to put them together. In this fusion, biomedicine will, we believe, set the agenda; materials science will follow, and materials scientists must learn biology to be effective.

Silicon Nanomembranes

MRS Bulletin ◽  
2007 ◽  
Vol 32 (1) ◽  
pp. 57-63 ◽  
Author(s):  
Max G. Lagally
Keyword(s):  
Quantum Dots ◽  
Single Crystals ◽  
San Francisco ◽  
Research Society ◽  
Strained Silicon ◽  
Spring Meeting ◽  
University Of Wisconsin ◽  
Materials Research ◽  
Silicon Nanomembranes

AbstractThis article is based on the presentation given by Max G. Lagally (University of Wisconsin–Madison) as part of Symposium X: Frontiers of Materials Research on April 18, 2006, at the Materials Research Society Spring Meeting in San Francisco.Structures with nanoscale dimensions are the essence of nanotechnology. Beginning with quantum dots and buckyballs, nanostructures now include nanotubes, rods, wires, and most recently, nanomembranes: very thin, large, freestanding or freefloating strain-engineered single crystals that can variously be made into tubes or other shapes, cut into millions of identical wires, or used as conformal sheets. This article provides a brief overview of the fabrication and properties of strained-silicon nanomembranes.

scholarly journals Estimating Jones and HOMFLY polynomials with one clean qubit

2009 ◽  
Vol 9 (3&4) ◽  
pp. 264-289
Author(s):  
S.P. Jordan ◽  
P. Wocjan
Keyword(s):  
Quantum Computing ◽  
Quantum Computer ◽  
Jones Polynomial ◽  
Single Variable ◽  
Initial State ◽  
Link Invariants ◽  
Root Of Unity ◽  
Complete Problem ◽  
The One ◽  
Homfly Polynomials

The Jones and HOMFLY polynomials are link invariants with close connections to quantum computing. It was recently shown that finding a certain approximation to the Jones polynomial of the trace closure of a braid at the fifth root of unity is a complete problem for the one clean qubit complexity class\cite{Shor_Jordan}. This is the class of problems solvable in polynomial time on a quantum computer acting on an initial state in which one qubit is pure and the rest are maximally mixed. Here we generalize this result by showing that one clean qubit computers can efficiently approximate the Jones and single-variable HOMFLY polynomials of the trace closure of a braid at \emph{any} root of unity.

scholarly journals Prospects for quantum computing: Extremely doubtful

2014 ◽  
Vol 33 ◽  
pp. 1460357 ◽  
Author(s):  
M. I. Dyakonov
Keyword(s):  
Quantum Computing ◽  
Large Scale ◽  
Quantum Computer ◽  
Chaotic Behavior ◽  
Physical World ◽  
The State ◽  
Strongly Nonlinear ◽  
Unitary Transformations ◽  
Strongly Nonlinear System ◽  
Limited Precision

The quantum computer is supposed to process information by applying unitary transformations to 2N complex amplitudes defining the state of N qubits. A useful machine needing N~103 or more, the number of continuous parameters describing the state of a quantum computer at any given moment is at least 21000 ~10300 which is much greater than the number of protons in the Universe. However, the theorists believe that the feasibility of large-scale quantum computing has been proved via the “threshold theorem”. Like for any theorem, the proof is based on a number of assumptions considered as axioms. However, in the physical world none of these assumptions can be fulfilled exactly. Any assumption can be only approached with some limited precision. So, the rather meaningless “error per qubit per gate” threshold must be supplemented by a list of the precisions with which all assumptions behind the threshold theorem should hold. Such a list still does not exist. The theory also seems to ignore the undesired free evolution of the quantum computer caused by the energy differences of quantum states entering any given superposition. Another important point is that the hypothetical quantum computer will be a system of 103 –106 qubits PLUS an extremely complex and monstrously sophisticated classical apparatus. This huge and strongly nonlinear system will generally exhibit instabilities and chaotic behavior.

Dripping, Jetting, Drops, and Wetting: The Magic of Microfluidics

MRS Bulletin ◽  
2007 ◽  
Vol 32 (9) ◽  
pp. 702-708 ◽  
Author(s):  
A. S. Utada ◽  
L.-Y. Chu ◽  
A. Fernandez-Nieves ◽  
D. R. Link ◽  
C. Holtze ◽  
...  
Keyword(s):  
Fluid Flow ◽  
San Francisco ◽  
Food Additives ◽  
Microfluidic Devices ◽  
Research Society ◽  
Harvard University ◽  
New Materials ◽  
Double Emulsions ◽  
Materials Research ◽  
Control Fluid

The following article is based on the Symposium X presentation given by David A. Weitz (Harvard University) on April 11, 2007, at the Materials Research Society Spring Meeting in San Francisco. The article describes how simple microfluidic devices can be used to control fluid flow and produce a variety of new materials. Based on the concepts of coaxial flow and hydrodynamically focused flow, used alone or in various combinations, the devices can produce precisely controlled double emulsions (droplets within droplets) and even triple emulsions (double emulsions suspended in a third droplet). These structures, which can be created in a single microfluidic device, have various applications such as encapsulants for drugs, cosmetics, or food additives.

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