Moiré Effect Could Enhance Neutron Interferometry

S ince the early days of quantum theory, its peculiarities have fascinated, worried, and even annoyed physicists. To investigate some of the most puzzling aspects of quantum mechanics, such as wave-particle duality and Schrödinger-cat states, experiments have often utilized the technique of perfect-crystal neutron interferometry, which involves interfering matter waves scattering off crystal planes [1]. But the demands of future experiments require that neutron interferometers advance in performance. A new neutron interferometer—developed by Dusan Sarenac, from the University of Waterloo in Canada, and colleagues—could outperform its predecessor in some important aspects [2]. Their approach utilizes the longknown moiré effect, in which overlaid stripe patterns create a wider periodic pattern. Moiré-based neutron interferometry could be easier to set up, less prone to environmental disturbance, and less wavelength-dependent than perfectcrystal interferometry. As the technique is developed further, it could measure the gravitational constant to higher precision than previous techniques and open new possibilities in materials science.