Theoretical and experimental advances are lately allowing more test of and refinement of Bohr’s thesis of wave-particle duality. That is the proposition that any experimental setup exhibiting interference of the de Broglie wave associated with momentum of any matter or field will, if altered to exhibit a particle form of that momentum, remove exhibition of the associated wave, such as interference patterns. So far, this division of the particle aspect and the wave aspect of the elementary entities, such as neutrons, electrons, phonons, or electrons, we manipulate today has held fast.
“Fair Sampling Perspective on an Apparent Violation of Duality”
E. Bolduc et al., 2012
In the event in which a quantum mechanical particle can pass from an initial state to a final state along two possible paths, the duality principle states that “the simultaneous observation of wave and particle behavior is prohibited” [Scully MO, Englert B-G, Walther H (1991) Nature 351:111–116]. Whereas wave behavior is associated with the observation of interference fringes, particle behavior generally corresponds to the acquisition of which-path information by means of coupling the paths to a measuring device or part of their environment. In this paper, we show how the consequences of duality change when allowing for biased sampling, that is, postselected measurements on specific degrees of freedom of the environment of the two-path state. Our work gives insight into a possible mechanism for obtaining simultaneous high which-path information and high-visibility fringes in a single experiment. Further, our results introduce previously unidentified avenues for experimental tests of duality.
“Experimental Observation of Simultaneous Wave and Particle Behavior in a Narrowband Single-Photon Wave Packet”
H. Yan et al., 2015
The Science News issue of May 30th describes what goes on in this experiment: “captures a single parcel of light morphing between wave and particle.”