Quantum Optics Journal Club

The Born rule is a central postulate of quantum mechanics stating that measurement probabilities are given by the squared magnitude of the wavefunction. A direct implication is the absence of genuine higher-order interference: all multi-path interference should be reducible to pairwise contributions, implying that there should be no genuine three-path or higher-order interference beyond what is expected from ordinary wave superposition. This prediction was tested experimentally in a three-slit photon experiment, which measured all combinations of open and closed slits to isolate a third-order interference term and found it consistent with zero. Related tests and proposals have been explored using matter waves, including atomic interferometry.

We propose extending these tests to massive particles using neutron orbital angular momentum (OAM) states. OAM modes provide a set of orthogonal, controllable alternatives that can be selectively prepared and combined, enabling a direct analogue of single-, double-, and triple-slit configurations in mode space. By inserting three independent grating arrays generating OAM and measuring the neutron intensity for all combinations of arrays, one can construct the same higher‑order interference metric used in optical experiments. This approach enables a quantitative test of the Born rule with neutrons, complements existing photon and atomic studies and provides a scalable, mode‑based platform for precision searches for higher‑order quantum interference.

Evidence of non-trivial photon–matter interaction has been observed in a 2-dimensional, spin-polarized, electronically excited ensemble of quantum dots. In particular, intense spikes in the relative frequency of |2⟩ photon events have been reproduced with a range of shapes of incident electronic current pulses where no analogous behavior in |1⟩ photon events has been observed. We hypothesize that superradiance may be responsible for the unique behavior and investigate this possibility by implementing a Monte Carlo Wave Function approach to simulate the dynamics of the system under a simple model Hamiltonian. Additionally, we use a simple theoretical model to predict whether superradiance is possible in the system in the first place.