QUANTUM MIRAGE(papppt)

QUANTUM MIRAGE - : 

QUANTUM MIRAGE -

ABSTRACT : 

ABSTRACT . The quantum mirage uses the wave nature of electrons to move the information, instead of a wire, so it has the potential to enable data transfer within future nano-scale electronic circuits so small that conventional wires do not work. It will be years before this technology becomes practical, but it could eventually yield computers that are many orders of magnitude smaller, faster, and less power-hungry than anything we can conceive today

Introduction : 

Introduction The term quantum mirage refers to a phenomenon that may make it possible to transfer data without conventional electrical wiring. Instead of forcing charge carriers through solid conductors, a process impractical on a microscopic scale, electron wave phenomena are made to produce effective currents. All moving particles have a wavelike nature. This is rarely significant on an everyday scale. But in atomic dimensions, where distances are measured in nanometers, moving particles behave like waves. This phenomenon is what makes the electron microscope workable. It is of interest to researchers in nanotechnology, who are looking for ways to deliver electric currents through circuits too small for conventional wiring.

WHAT IS IT? : 

WHAT IS IT? A quantum mirage is a spot where electron waves are focused so they reinforce each other. The result is an energy hot zone, similar to the acoustical hot zones observed in concrete enclosures, or the electromagnetic wave focus of a dish antenna. In the case of electron waves, the enclosure is called a quantum corral. An elliptical corral produces mirages at the foci of the ellipse. A typical quantum corral measures approximately 20 nm long by 10 nm wide. By comparison, the range of visible wavelengths is approximately 390 nm (violet light) to 750 nm (red light). One nanometer is 10-9 meter, or a millionth of a millimeter.

What caused its birth? : 

What caused its birth? One of the biggest obstacles to the continued shrinkage of electronic elements within integrated circuits is the connection between them. As the size of these elements decreases, so must the size of the wires that carry electrons from one to another. But beyond a certain point, a wire's ability to conduct electrons is significantly hampered, preventing the message from getting through. Therefore, if nanotechnology and atomic-scale computers are to become a reality, an alternative means of sending information between circuit elements must be developed.

CREATION… : 

CREATION… To create the quantum mirage, the scientists first moved several dozen cobalt atoms on a copper surface into an ellipse-shaped ring. As Michael Crommie, Lutz and Eigler had shown in 1993, the ring atoms acted as a "quantum corral" -- reflecting the copper's surface electrons within the ring into a wave pattern predicted by quantum mechanics.  When a single cobalt atom (purple peak) is placed at one of the two focus points of the elliptical ring, some of its properties suddenly appear at the other focus (the purple spot in the lower left), where no atom exists. The size and shape of the ellipse determines where information moves within the ring. The IBM scientists said they have built and tested elliptical corrals up to 20 nanometers long with the width as little as half that. The electron density and intensity of the mirage depends on the quantum state, not the distance between the foci.

MAGNIFIED VIEW : 

MAGNIFIED VIEW

The kondo effect : 

The kondo effect Cobalt atoms exhibit a property called a magnetic moment. When a cobalt atom is deposited on a metallic, nonmagnetic surface (such as copper), the electron sea produces what is called the Kondo effect, after Japanese physicist Jun Kondo, who explained the phenomenon in 1964. Basically, the electrons near the atom align themselves to offset its magnetic moment, effectively canceling it out. The Kondo effect is highly localized and easily detected using spectroscopic techniques.

Experimental amaze! : 

Experimental amaze! When the IBM scientists placed a single cobalt atom within the quantum corral, they saw the Kondo effect at the atom's location, as expected. But when they moved this atom to one of the ellipse's foci, something amazing happened: the Kondo effect also appeared at the other focus, even though no atom was there. The "phantom" atom is called a quantum mirage; information about the real atom is transmitted to the other focus of the ellipse via the wavelike medium of the electron sea without using any wires.

Applications : 

Applications The presence or absence of a quantum mirage might be used to represent one bit of data in a region far smaller than any current electronic device can manage. The quantum mirage technique permits us to do some very interesting scientific experiments such as remotely probing atoms and molecules, studying the origins of magnetism at the atomic level and ultimately manipulating individual electron or nuclear spins.

Conclusion : 

Conclusion Significant improvements in quantum mirage are still needed before this method becomes useful in actual circuits. Making each ellipse with the STM is currently impractically slow. They would have to be easily and rapidly produced, connections to other components would also have to be devised and a rapid and power-efficient way to modulate the available quantum states would need to be developed. Many barriers must be overcome to make this scientific discovery useful in the above mentioned ways. But if it can be developed, the quantum mirage could enable the miniaturization of electronic circuits and could eventually yield computers that are many orders of magnitude smaller, faster, and less power-hungry than anything we can conceive today.