The Physics of Information Technology

by Neil Gershenfeld

• ISBN13: 9780521580441
• ISBN10: 0521580447
• Format: Hardcover
• Copyright: 2000-10-16
• Publisher: Cambridge University Press

Summary

The Physics of Information Technology explores the familiar devices that we use to collect, transform, transmit, and interact with electronic information. Many such devices operate surprisingly close to very many fundamental physical limits. Understanding how such devices work, and how they can (and cannot) be improved, requires deep insight into the character of physical law as well as engineering practice. The book starts with an introduction to units, forces, and the probabilistic foundations of noise and signalling, then progresses through the electromagnetics of wired and wireless communications, and the quantum mechanics of electronic, optical, and magnetic materials, to discussions of mechanisms for computation, storage, sensing, and display. This self-contained volume will help both physical scientists and computer scientists see beyond the conventional division between hardware and software to understand the implications of physical theory for information manipulation.

Author Biography

Professor Neil Gershenfeld leads the Physics and Media Group at the MIT Media Lab, and directs the Things That Think research consortium. His laboratory investigates the relationship between the content of information and its physical representation, from developing molecular quantum computers to virtuosic musical instruments. Dr Gershenfeld has a B.A. in Physics from Swarthmore College, a Ph.D. from Cornell University, was a Junior Fellow of the Harvard Society of Fellows, and a member of the research staff at Bell Labs

Table of Contents

Preface	xiii
Introduction	1	(2)
Interactions, Units, and Magnitudes	3	(11)
Units	3	(4)
Particles and Forces	7	(3)
Orders of Magnitude	10	(2)
Selected References	12	(1)
Problems	13	(1)
Noise in Physical Systems	14	(22)
Random Variables	14	(4)
Expectation Values	14	(1)
Spectral Theorems	15	(3)
Probability Distributions	18	(4)
Binomial	18	(1)
Poisson	18	(1)
Gaussian	19	(2)
Central Limit Theorem	21	(1)
Noise Mechanisms	22	(5)
Shot Noise	22	(1)
Johnson Noise	23	(1)
1/f Noise and Switching Noise	24	(1)
Amplifier Noise	25	(2)
Thermodynamics and Noise	27	(7)
Thermodynamics and Statistical Mechanics	27	(3)
Equipartition Theorem	30	(1)
Fluctuation--Dissipation Theorem	31	(3)
Selected References	34	(1)
Problems	35	(1)
Information in Physical Systems	36	(15)
Information	36	(4)
Channel Capacity	40	(2)
The Gaussian Channel	42	(3)
Fisher Information	45	(3)
Information and Thermodynamics	48	(1)
Selected References	49	(1)
Problems	49	(2)
Electromagnetic Fields and Waves	51	(25)
Vector Calculus	51	(5)
Vectors	51	(2)
Differential Operators	53	(2)
Integral Relationships	55	(1)
Statics	56	(10)
Electrostatics	56	(4)
Magnetostatics	60	(3)
Multipoles	63	(3)
Dynamics	66	(5)
Maxwell's Equations	66	(2)
Boundary Conditions	68	(2)
Electromagnetic Units	70	(1)
Radiation and Energy	71	(3)
Waves	71	(1)
Electromagnetic Energy	72	(2)
Selected References	74	(1)
Problems	74	(2)
Circuits, Transmission Lines, and Waveguides	76	(22)
Circuits	76	(5)
Current and Voltage	76	(1)
Kirchhoff's Laws	77	(1)
Resistance	77	(2)
Power	79	(1)
Capacitance	79	(1)
Inductance	80	(1)
Wires and Transmission Lines	81	(9)
Skin Depth	81	(2)
Transmission Lines	83	(2)
Wave Solutions	85	(2)
Reflections and Terminations	87	(3)
Waveguides	90	(5)
Governing Equations	90	(2)
Rectangular Waveguides	92	(1)
Circular Waveguides	93	(1)
Dielectric Waveguides and Fiber Optics	93	(2)
Selected References	95	(1)
Problems	96	(2)
Antennas	98	(14)
Time-Dependent Potentials	98	(4)
Dipole Radiation	102	(4)
Infinitesimal Length	102	(2)
Finite Length	104	(2)
Duality and Reciprocity	106	(3)
Antenna Types	109	(2)
Selected References	111	(1)
Problems	111	(1)
Optics	112	(16)
Reflection and Refraction	112	(5)
Geometrical Optics	117	(5)
Ray Matrices	119	(1)
Optical Transforms	120	(2)
Beyond Geometrical Optics	122	(4)
Selected References	126	(1)
Problems	126	(2)
Lensless Imaging and Inverse Problems	128	(13)
Matched Filters and Synthetic Lenses	128	(3)
Coherent Imaging	131	(3)
Computed Tomography	134	(1)
Magnetic Resonance Imaging	135	(3)
Inverse Problems	138	(1)
Selected References	139	(1)
Problems	139	(2)
Semiconductor Materials and Devices	141	(24)
Quantum Statistical Mechanics	141	(2)
Electronic Structure	143	(8)
Junctions, Diodes, and Transistors	151	(5)
Logic	156	(5)
Limits	161	(2)
Selected References	163	(1)
Problems	163	(2)
Generating, Detecting, and Modulating Light	165	(22)
Generation	165	(7)
Incandescence	165	(2)
Luminescence: LEDs, Lasers, and Flat Panels	167	(5)
Detection	172	(5)
Modulation	177	(9)
Polarization	177	(2)
Liquid Crystals	179	(4)
Smoke and Mirrors	183	(3)
Selected References	186	(1)
Problems	186	(1)
Magnetic Storage	187	(16)
Magnetism	187	(10)
Diamagnetism	189	(1)
Paramagnetism	190	(2)
Ferro-, Antiferro-, and Ferri-magnetism	192	(5)
Magnetic Recording	197	(4)
Magnetic Media	197	(1)
Magnetic Recording	198	(2)
Recording Systems	200	(1)
Selected References	201	(1)
Problems	201	(2)
Measurement and Coding	203	(28)
Instrumentation	203	(8)
Amplifiers	203	(4)
Grounding, Shielding, and Leads	207	(2)
Bridges	209	(2)
Modulation and Detection	211	(11)
Synchronous Detection	211	(2)
Phase Detection and Encoding	213	(3)
Spread Spectrum	216	(4)
Digitization	220	(2)
Coding	222	(7)
Compression	222	(3)
Error Correction	225	(2)
Channel Coding	227	(1)
Cryptography	228	(1)
Selected References	229	(1)
Problems	229	(2)
Transducers	231	(21)
Many-Body Effects	231	(5)
Superconductivity	232	(3)
SQUIDs	235	(1)
Non-Equilibrium Thermodynamics	236	(7)
Thermoelectricity	239	(3)
Piezoelectricity	242	(1)
Relativity	243	(8)
Clocks	243	(3)
Time	246	(3)
Position	249	(2)
Selected References	251	(1)
Problems	251	(1)
Quantum Computing and Communications	252	(34)
Quantum Mechanics	253	(13)
States and Operators	253	(5)
Angular Momentum	258	(5)
Density Matrices	263	(3)
Information	266	(3)
Communications	269	(6)
Cryptography	269	(1)
Circuits	270	(1)
Teleportation	271	(2)
Error Correction	273	(2)
Computation	275	(9)
Searching	276	(2)
Transforms and Factoring	278	(3)
Simulation	281	(1)
Experimental Implementation	282	(2)
Selected References	284	(1)
Problems	285	(1)
Appendix 1 Problem Solutions	286	(61)
A1.1 Introduction	286	(1)
A1.2 Interactions, Units, and Magnitudes	286	(5)
A1.3 Noise in Physical Systems	291	(5)
A1.4 Information in Physical Systems	296	(4)
A1.5 Electromagnetic Fields and Waves	300	(5)
A1.6 Circuits, Transmission Lines, and Wave Guides	305	(4)
A1.7 Antennas	309	(2)
A1.8 Optics	311	(6)
A1.9 Lensless Imaging and Inverse Problems	317	(5)
A1.10 Semiconductor Materials and Devices	322	(5)
A1.11 Generating, Modulating, and Detecting Light	327	(3)
A1.12 Magnetic Storage	330	(4)
A1.13 Measurement and Coding	334	(4)
A1.14 Transducers	338	(4)
A1.15 Quantum Computing and Communication	342	(5)
Bibliography	347	(15)
Index	362