QUANTUM COMPUTERS




Anish J Lal
6202, S7 R

Marian Engineering College

Abstract

A quantum computer is a device for computation that makes direct use of quantum mechanical phenomena, such as superposition and entanglement, to perform operations on data. The basic principle behind quantum computation is that quantum properties can be used to represent data and perform operations on these data. Quantum computers can solve certain problems much faster than any of our current classical computers. ....etc

[:=Read Full Message Here=:]

Since it first appeared on the cover of Nature in February 2000, the quantum mirage? has featured on posters, calendars, websites and the covers of various books and magazines. The image ? which was obtained using a scanning tunnelling microscope ? shows the electronic wavefunctions inside an elliptical ?quantum corral? made of cobalt atoms on a copper surface. It was created by Hari Manoharan, Christopher Lutz and Don Eigler of the IBM Almaden Research Center in California. In 1990, working with Erhard Schweizer, Eiger spelt out the letters ?I ....etc

[:=Read Full Message Here=:]

The infrastructure of the Information Age has to date relied upon advances in microelectronics to produce integrated circuits that continually become smaller, better, and less expensive. The emergence of photonics, where light rather than electricity is manipulated, is posed to further advance the Information Age. Central to the photonic revolution is the development of miniature light sources such as the Quantum dots(QDs).

Today, Quantum Dots manufacturing has been established to serve new datacom and telecom markets. Recent progress in mic ....etc

[:=Read Full Message Here=:]

Quantum Wells, Quantum Wire, and Quantum Dots




I'd like to explore the material known as Wellstone. There are some interesting aspects to this material, and it is written about in Hacking Matter by Will McCarthy. It is not necessarily nanotechnology, so much as it is quantum level materials and bio-molecular control over nano sized or meso-sized particles.
We will return to the world of Nanotechnology and DNA computing shortly, for now - let's talk about Wellstone.

Definit ....etc

[:=Read Full Message Here=:]

Definition

The subject of quantum computing brings together ideas from classical information theory, computer science, and quantum physics. This document aims to summarize not just quantum computing, but the whole subject of quantum information theory. It turns out that information theory and quantum mechanics fit together very well. In order to explain their relationship, the paper begins with an introduction to classical information theory .The principles of quantum mechanics are then outlined.

The EPR-Bell correlation and quantum enta ....etc

[:=Read Full Message Here=:]

Definition
Quantum cryptography is an effort to allow two users of a common communication channel to create a body of shared and secret information. This information, which generally takes the form of a random string of bits, can then be used as a conventional secret key for secure communication. It is useful to assume that the communicating parties initially share a small amount of secret information, which is used up and then renewed in the exchange process, but even without this assumption exchanges are possible.

The advantage of quantum ....etc

[:=Read Full Message Here=:]

To explain what makes quantum computers so different from their classical counterparts we begin by having a closer look at a basic chunk of information namely one bit. A bit is the basic unit of information in a digital computer. From a physical point of view, a bit is a physical system which can be prepared in one of the two different states representing two logical values --- no or yes, false or true, or simply 0 or 1. For example, in digital computers, the voltage between the plates in a capacitor represents a bit of information: a charged c ....etc

[:=Read Full Message Here=:]

The promise of quantum computers is tantalizingly great: near-instantaneous problem solving, and perfectly secure data transmission. For the most part, however, small-scale demonstrations of quantum computation remain isolated in labs throughout the world. Now, Prem Kumar, a professor of electrical engineering and computer science at Northwestern University, has taken a step toward making quantum computing more practical. Kumar and his team have shown that they can build a quantum logic gate--a fundamental component of a quantum computer--withi ....etc

[:=Read Full Message Here=:]

Definition
The history of computer technology has involved a sequence of changes from one type of physical realisation to another --- from gears to relays to valves to transistors to integrated circuits and so on. Today's advanced lithographic techniques can squeeze fraction of micron wide logic gates and wires onto the surface of silicon chips. Soon they will yield even smaller parts and inevitably reach a point where logic gates are so small that they are made out of only a handful of atoms; i.e. the size of the logic gates become comparable ....etc

[:=Read Full Message Here=:]

Teleportation is the name given by science fiction writers to the feat of making an object or person disintegrate in one place while a perfect replica appears somewhere else. how this is accomplished is usually not explained in detail but the general idea seems to he that the original object is scanned in such a way as to extract all the information from it, then this information is transmitted to the receiving location and used to construct the replica, not necessarily from the actual material of the original, but perhaps from atoms of the sam ....etc

[:=Read Full Message Here=:]