Researchers at the Joint Quantum Institute (JQI), a collaboration of the National Institute of Standards and Technology and the University of Maryland at College Park, can speed up photons (particles of light) to seemingly faster-than-light speeds through a stack of materials by adding a single, strategically placed layer. This experimental demonstration confirms intriguing quantum-physics predictions that light's transit time through complex multilayered materials need not depend on thickness, as it does for simple materials such as glass, but rather on the order in which the layers are stacked. This is the first published study of this dependence with single photons.

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