Periodic squeezing in a polariton Josephson junction

Abstract

The use of a Kerr nonlinearity to generate squeezed light is a well-known way to surpass the quantum noise limit along a given field quadrature. Nevertheless, in the most common regime of weak nonlinearity, a single Kerr resonator is unable to provide the proper interrelation between the field amplitude and squeezing required to induce a sizable deviation from Poissonian statistics. We demonstrate experimentally that weakly coupled bosonic modes allow exploration of the interplay between squeezing and displacement, which can give rise to strong deviations from the Poissonian statistics. In particular, we report on the periodic bunching in a Josephson junction formed by two coupled exciton-polariton modes. Quantum modeling traces the bunching back to the presence of quadrature squeezing. Our results, linking the light statistics to squeezing, are a precursor to the study of nonclassical features in semiconductor microcavities and other weakly nonlinear bosonic systems.

Nonclassical statistics from a polaritonic Josephson junction

“…While it doesn't demonstrate a nonclassical signature, the experimental observation of such a feature is less challenging than the antibunching, while still providing evidence for the mechanism as recently reported in Ref. [46].…”

“…However as discussed above, the time t m to maximize the sub-Poissonian character becomes a crucial quantity from an experimental point of view. Indeed to observe the nonclassical signature one has to favor a situation where it occurs at short times before the signal-to-noise ratio becomes too small [31,46]. The most favorable situation is found for a large yet imperfect imbalance, i.e., 0 z 0 < 1.…”

“…While streak cameras currently demonstrate resolutions of a few picoseconds [31], their quantum efficiency of less than 1% might be too low to detect sufficient counts during reasonable integration times [46]. On the other hand, superconductorbased detectors demonstrate a very high efficiency up to 90% at the price of a lower time resolution in the range of tens of picoseconds.…”

Maximizing entanglement in bosonic Josephson junctions using shortcuts to adiabaticity and optimal control

“…Observe now that if D was equal to zero then one of the eigenvalues, let us say λ 3 , would also be zero. Since D is actually a very small perturbation, we can assume that λ 3 remains close to zero and ignore the power terms l l , thus we can omit the third eigenvalue in (10). We end up with the following expression [51]…”

“…Mathematically, this system is described as two interacting nonlinear quantum oscillators. It has been implemented experimentally in various physical settings, with Bose-Einstein condensates (BECs) confined in optical traps [6], atom chip [7], semiconductor microcavities (exciton-polariton systems) [8][9][10], superconducting circuits [11] and photonic systems [12]. It provides an ideal model to study correlations and entanglement in quantum systems.…”