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A matter wave clock is a type of clock whose principle of operation makes use of the apparent wavelike properties of matter. Matter waves were first proposed by Louis de Broglie and are sometimes called de Broglie waves. They form a key aspect of wave-particle duality and experiments have since supported the idea. The wave associated with a particle of a given mass, such as an atom, has a defined frequency, and a fixed duration of one cycle from peak to peak that is sometimes called its ''Compton periodicity''. Such a matter wave has the characteristics of a simple clock, in that it marks out fixed and equal intervals of time. The twins paradox arising from Einstein's theory of relativity means that a moving particle will have a slightly different period from a stationary particle. Comparing two such particles allows the construction of a practical "Compton clock".〔Lan, S-Y et. al.; "A Clock Directly Linking Time to a Particle's Mass", ''Science'' 1 February 2013: Vol. 339 no. 6119 pp. 554-557 〕 ==Matter waves as clocks== De Broglie proposed that the frequency ''f'' of a matter wave equals ''E''/''h'', where ''E'' is the total energy of the particle and ''h'' is Planck's constant. For a particle at rest, the relativistic equation ''E''=''mc''2 allows the derivation of the ''Compton frequency'' ''f'' for a stationary massive particle, equal to ''mc''2/''h''. De Broglie also proposed that the wavelength ''λ'' for a moving particle was equal to ''h''/''p'' where ''p'' is the particle's momentum. The period (one cycle of the wave) is equal to 1/''f''. This precise ''Compton periodicity'' of a matter wave is said to be the necessary condition for a clock, with the implication that any such matter particle may be regarded as a fundamental clock. This proposal has been referred to as "A rock is a clock."〔Sanders, R.; "A rock is a clock: physicist uses matter to tell time", ''UC Berkeley News Center'', () (retrieved 4 July 2014)〕 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「Matter wave clock」の詳細全文を読む スポンサード リンク
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