\contentsline {section}{\numberline {\uppercase {i}}Introduction}{3}\contentsline {section}{\numberline {\uppercase {ii}}Computation in Classical and Quantum Physics}{4}\contentsline {subsection}{\numberline {A}Classical Gates}{4}\contentsline {subsection}{\numberline {B}Quantum Gates}{5}\contentsline {subsection}{\numberline {C}Quantum Entanglement}{6}\contentsline {section}{\numberline {\uppercase {iii}}Simple Quantum Networks}{6}\contentsline {subsection}{\numberline {A}Simple Arithmetic}{7}\contentsline {subsection}{\numberline {B}Plain adder}{7}\contentsline {subsection}{\numberline {C}Garbage Disposal}{8}\contentsline {subsection}{\numberline {D}Deutsch's Problem}{9}\contentsline {section}{\numberline {\uppercase {iv}}Outline of Quantum Factorization}{10}\contentsline {section}{\numberline {\uppercase {v}}How to realize a Quantum Computer}{12}\contentsline {subsection}{\numberline {A}The ion trap quantum computer}{12}\contentsline {subsection}{\numberline {B}The implementation of the CNOT gate}{13}\contentsline {section}{\numberline {\uppercase {vi}}Decoherence and Quantum Computation}{15}\contentsline {subsection}{\numberline {A}Decoherence of entangled states}{15}\contentsline {subsection}{\numberline {B}A general error model}{16}\contentsline {subsection}{\numberline {C}Quantum error correction}{17}\contentsline {section}{\numberline {\uppercase {vii}}Summary and Future Prospects}{19}\contentsline {section}{\numberline {\uppercase {viii}} Acknowledgements}{19}