Modification of the two-slit experiment with a single photon

军利 陈

Tore Wessel-Berg

G. Sampath

Summary. A modified version of the two-slit experiment is proposed in which the moveable detector/counter used to obtain the fringe distribution by counting single photons at different positions on the screen plane is replaced with a mirror positioned at an angle to the screen plane. A single photon arriving at the mirror through one of the slits is reflected at one of two angles along one of two divergent paths. It is then detected by one of two detectors, one on each of the paths, for different positions of the mirror on the screen plane. This modification results in the ability to generate which way information based on the path taken by the reflected photon as well as the distribution of photon counts on the screen plane, one for each slit. Since the photon does not experience any change other than the reflection at the mirror the question whether fringes are also present because of a priori interference effects when no mirror is present can be answered by examining the two a posteriori distributions. Three possible outcomes are considered and explanations proposed for them. The experiment is shown to be feasible with existing technology and can be performed in most physics laboratories.

L. P. Withers, Frank A. Narducci

The recent single-photon double-slit experiment of Steinberg et al., based on a weak measurement method proposed by Wiseman, showed that, by encoding the photon’s transverse momentum behind the slits into its polarization state, the momentum profile can subsequently be measured on average, from a difference of the separated fringe intensities for the two circular polarization components. They then integrated the measured average velocity field, to obtain the average trajectories of the photons enroute to the detector array. In this paper, we propose a modification of their experiment, to demonstrate that the average particle velocities and trajectories change when the mode of detection changes. The proposed experiment replaces a single detector by a pair of detectors with a given spacing between them. The pair of detectors is configured so that it is impossible to distinguish which detector received the particle. The pair of detectors is then analogous to the simple pair of slits, in that it is impossible to distinguish which slit the particle passed through. To establish the paradoxical outcome of the modified experiment, the theory and explicit three-dimensional formulas are developed for the bilocal probability and current densities, and for the average velocity field and trajectories as the particle wavefunction propagates in the volume of space behind the Gaussian slits. Examples of these predicted results are plotted. Implementation details of the proposed experiment are discussed.

Mohamed Saladin El Naschie

Siddhant Das, Dirk-André Deckert, Leopold Kellers +2 more