Beyond Hanbury Brown and Twiss: Correlating Light as Particle AND Wave

H.-S. Sim, Eugene V. Sukhorukov

Eva Zakka-Bajjani, Joseph Dufouleur, P. Roche +2 more

Yanhua H. Shih, Alexander V. Sergienko

Tabish Qureshi, Ushba Rizwan

The Hanbury Brown–Twiss (HBT) effect, at the quantum level, is essentially an interference of one particle with another, as opposed to interference of a particle with itself. Conventional treatments of identical particles encounter difficulties while dealing with entanglement. A recently introduced label-free approach to indistinguishable particles is described, and is used to analyze the HBT effect. Quantum wave-packets have been used to provide a better understanding of the quantum interpretation of the HBT effect. The effect is demonstrated for two independent particles governed by Bose–Einstein or Fermi–Dirac statistics. The HBT effect is also analyzed for pairs of entangled particles. Surprisingly, entanglement has almost no effect on the interference seen in the HBT effect. In the light of the results, an old quantum optics experiment is reanalyzed, and it is argued that the interference seen in that experiment is not a consequence of non-local correlations between the photons, as is commonly believed. Quanta 2017; 6: 61–69.

CT Chantler

Silva, B., Carlos Sánchez Muñoz, Dario Ballarini +8 more

The Hanbury Brown-Twiss effect is one of the celebrated phenomenologies of modern physics that accommodates equally well classical (interferences of waves) and quantum (correlations between indistinguishable particles) interpretations.The effect was discovered in the late thirties with a basic observation of Hanbury Brown that radio-pulses from two distinct antennas generate signals on the oscilloscope that wiggle similarly to the naked eye.When Hanbury Brown and his mathematician colleague Twiss took the obvious step to propose bringing the effect in the optical range, they met with considerable opposition as single-photon interferences were deemed impossible.The Hanbury Brown-Twiss effect is nowadays universally accepted and, being so fundamental, embodies many subtleties of our understanding of the wave/particle dual nature of light.Thanks to a novel experimental technique, we report here a generalized version of the Hanbury Brown-Twiss effect to include the frequency of the detected light, or, from the particle point of view, the energy of the detected photons.Our source of light is a polariton condensate, that allows high-resolution filtering of a spectrally broad source with a high degree of coherence.In addition to the known tendencies of indistinguishable photons to arrive together on the detector, we find that photons of different colors present the opposite characteristic of avoiding each others.We postulate that fermions can be similarly brought to exhibit positive (bosonlike) correlations by frequency filtering.