Consequences of dynamical diffraction and the Sagnac effect in LLL perfect single crystal interferometers

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• 作者：Kenneth C. Littrell
• 关键词：Neutron interferometry ; Sagnac effect ; Dynamical diffraction
• 刊名：Physica B
• 出版年：2006
• 出版时间：15 November 2006
• 年：2006
• 卷：385-386
• 期：Part 2
• 页码：1371-1373
• 全文大小：206 K

文摘

The LLL perfect single crystal interferometer is an exciting tool for exploring a variety of topics of fundamental importance in understanding quantum mechanics and for precision measurement of neutron scattering lengths. One of the limiting factors in many neutron interferometry experiments is the overall size of the interferometer. Hence, ever-larger interferometers would seem to be preferable. However, the theory of dynamical diffraction predicts that neutrons that nearly but not exactly satisfy the Bragg condition take different trajectories through a crystal, giving rise to multiple mutually interfering wavefunctions that all contribute to the measurement of an interferogram. This complexity results in shifts in the measured phase difference and a loss of contrast of the interferogram in the presence of potentials which are dependent on the spatial differences between the trajectories of the neutron through the interferometer. This effect has already been experimentally verified for the gravitational potential. Here we discuss the similar effects of dynamical diffraction on the phase shift due to the Sagnac effect and their consequences on the observable contrast in large-scale interferometers.