There is, I think, something ethereal about i —the square root of minus one. I remember first hearing about it at school. It seemed an odd beast at that time—an intruder hovering on the edge of reality.

Usually familiarity dulls this sense of the bizarre, but in the case of i it was the reverse: over the years the sense of its surreal nature intensified. It seemed that it was impossible to write mathematics that described the real world in …

I and i

다중혈관 관상동맥 환자에서 y-문합을 이용하여 양쪽 내흉동맥만을 사용한 우회술의 조기 성적

Part I. Fundamental Concepts: 1. Introduction and overview 2. Introduction to quantum mechanics 3. Introduction to computer science Part II. Quantum Computation: 4. Quantum circuits 5. The quantum Fourier transform and its application 6. Quantum search algorithms 7. Quantum computers: physical realization Part III. Quantum Information: 8. Quantum noise and quantum operations 9. Distance measures for quantum information 10. Quantum error-correction 11. Entropy and information 12. Quantum information theory Appendices References Index.

Quantum Computation and Quantum Information

Current research into semiconductor clusters is focused on the properties of quantum dots-fragments of semiconductor consisting of hundreds to many thousands of atoms-with the bulk bonding geometry and with surface states eliminated by enclosure in a material that has a larger band gap. Quantum dots exhibit strongly size-dependent optical and electrical properties. The ability to join the dots into complex assemblies creates many opportunities for scientific discovery.

Semiconductor Clusters, Nanocrystals, and Quantum Dots

Recent years have witnessed many breakthroughs in research on graphene (the first two-dimensional atomic crystal) as well as a significant advance in the mass production of this material. This one-atom-thick fabric of carbon uniquely combines extreme mechanical strength, exceptionally high electronic and thermal conductivities, impermeability to gases, as well as many other supreme properties, all of which make it highly attractive for numerous applications. Here we review recent progress in graphene research and in the development of production methods, and critically analyse the feasibility of various graphene applications.

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A roadmap for graphene

A method for adaptive spectral sensing developed for a two-dimensional image made up of picture elements. The method calls for illuminating at least one of the picture elements with an input light and deriving a time-varying spectral signal from the input light for that picture element. The time-varying spectral signal is processed with a time-varying reference signal by using a mathematical function such as convolution, multiplication, averaging, integrating, forming an inner product, matched filtering, addition, subtraction or division to obtain a processed output value for the picture element and this output value is then used in determining a spectral characteristic of the input light. The time-varying spectral signal is conveniently derived by optical filtering of the input light yielding an optical time-varying spectral signal. This method can be used by itself or in combination with at least one other adaptive technique such as adaptive spatial sensing and/or adaptive temporal sensing.

Methods for adapative spectral, spatial and temporal sensing for imaging applications

An arrangement for performing an optical logic operation The optical logic arrangement comprises a plurality of reflection holograms positioned in a two-dimensional array for optically interconnecting a similar plurality of optically nonlinear self electro-optic effect devices also positioned in a two-dimensional array Each self electro-optic effect device is responsive to control light beams received on either side of the device array for emitting an output light beam that is a nonlinear function of the control light beams Accordingly, each self electro-optic effect device can regenerate light beams and perform an optical logic function In response to an output light beam from a specified self electro-optic effect logic element, the associated reflection hologram originates an individual control light beam to one or more designated self electro-optic effect logic elements in the logic array Consequently, the self electro-optic effect logic elements may be optically interconnected to perform a combination of sequential and combinational logic operations including those, for example, of an optical digital processor

Optical logic arrangement with self electro-optic effect devices

We demonstrate operation of a wavelength division multiplexed chip-to-chip optical interconnect using surface-normal electroabsorption modulators, and a modelocked laser as a single broadband source. The link was successfully operated at 80 Mb/s. While this rate was limited by the repetition rate of the modelocked source, individual CMOS circuits and optoelectronic devices have been shown to work at data rates approaching 1 Gb/s.

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Wavelength division multiplexed optical interconnect using short pulses

We examine, experimentally and theoretically, the effects of excitons in optical measurements of resonant coupling of quantum wells. We find that the exciton line splittings do not correspond directly to the underlying electron levels, which leads to differences in the bias fields for resonance of, e.g., \ensuremath{\sim}10%. We construct a variational model of excitons in coupled wells and successfully compare this model with measured splittings near the resonance between the first and second electron levels of adjacent wells, deducing the actual conditions for coupling of the ``bare'' electron levels.

Excitons in resonant coupling of quantum wells.

We propose a device that can take an arbitrary monochromatic input beam and couple it into a single-mode guide or beam. Simple feedback loops from detectors to modulator elements allow the device to adapt automatically to any specific input beam form. Potential applications include automatic compensation for misalignment and defocusing of an input beam, coupling of complex modes or multiple beams from fibers or free space to single-mode guides, and retaining coupling to a moving source. Straightforward extensions allow multiple different overlapping orthogonal input beams to be separated simultaneously to different single-mode guides with no splitting loss in principle. The approach is suitable for implementation in integrated optics platforms that offer elements such as phase shifters, Mach-Zehnder interferometers, grating couplers, and integrated monitoring detectors, and the basic approach is applicable in principle to other types of waves, such as microwaves or acoustics.

David A. B. Miller

Papers

Methods for adapative spectral, spatial and temporal sensing for imaging applications

Optical logic arrangement with self electro-optic effect devices

Wavelength division multiplexed optical interconnect using short pulses

Excitons in resonant coupling of quantum wells.

Self-aligning universal beam coupler