Photon Bunching in a Rotating Reference Frame

Abstract

Although quantum physics is well understood in inertial reference frames (flat spacetime), a current challenge is the search for experimental evidence of non-trivial or unexpected behaviour of quantum systems in non-inertial frames. Here, we present a novel test of quantum mechanics in a non-inertial reference frame: we consider Hong-Ou-Mandel (HOM) interference on a rotating platform and study the effect of uniform rotation on the distinguishability of the photons. Both theory and experiments show that the rotational motion induces a relative delay in the photon arrival times at the exit beamsplitter and that this delay is observed as a shift in the position of the HOM dip. This experiment can be extended to a full general relativistic test of quantum physics using satellites in Earth orbit and indicates a new route towards the use of photonic technologies for investigating quantum mechanics at the interface with relativity. * miles.padgett@glasgow.ac.uk, daniele.faccio@glasgow.ac.uk † These authors contributed equally.

Revealing and concealing entanglement with noninertial motion

“…We first provide a theoretical description of quantum experiments on a rotating platform starting from the Hamiltonian on a generic Hilbert space which we then apply to study photon-interferometry experiments. The model also re- * m.toros@ucl.ac.uk † daniele.faccio@glasgow.ac.uk covers the results for the Sagnac effect in the quantum regime [17] as well as for the recent demonstration of photon bunching in a rotating reference frame [16]. Theoretical model.…”

“…For example, if we consider spontaneous parametric down conversion (SPDC) type I two-photon generation [29] we again find the coincidence probability in Eq. (16). It would thus seem that entanglement in combination with rotational motion leaves no trace on the photon coincidence rate, P (2) , measurement.…”

On-demand quantum correlation control using coherent photons

“…Because the coherence length of commercially available lasers is much longer than its wavelength λ , and photon indistinguishability for the quantum correlation (2) ( ) is sustained under coherence [35,36], the concept of coincidence detection in (2) ( ) is conceptually alleviated when the wave nature of photons is emphasized. In that sense, a collective control of entangled (wave) pairs can be achieved from a coherent system with a proper phase control [28,32,37].…”

“…Because of Δ = 1 according to the uncertainty principle, the modulation depth of 〈sin ( ) 2 〉 repidly decreases as τΔ increases, resulting in the transient effect as observed experimentally [32]. On the contrary of conventional understanding, this is a very important result in the interpretation of the HOM dip for the origin of (2) (0) in terms of the wave nature.…”

“…Over the last several decades, (2) correlation has been studied using SPDC- [2,[30][31][32] and other method- [21,22] generated entangled photon pairs, where the amplitudes of the signal and idler photons are denoted by and , repsectively:…”