Conference Agenda

We study the driven-dissipative dynamics of one-dimensional photonic resonator arrays functioning as broadband quantum amplifiers [1,2]. We first analyze linear resonators with incoherent pumping, complex nearest-neighbor hopping, and dissipation. We identify conditions for a steady-state topological phase with broken time-reversal symmetry, where photonic signals propagating along the array are directionally amplified. Remarkably, this amplification is topologically protected against disorder, broadband, and near quantum-limited, with gain growing exponentially with system size [2].

We then explore the realization of such topological amplification using coupled Kerr-nonlinear resonators driven by a coherent pump with linearly increasing phase [3]. This induces parametric couplings with complex phases inherited from the pump, breaking time-reversal symmetry and enabling topological amplification via four-wave mixing. Exploiting non-linearities, we thus alleviate the need for incoherent pumping or Floquet engineering. We characterize the rich topological phase diagram [4] and the non-linear dynamics of the emergent topological phase transition [5]. Finally, we propose a microwave implementation using Josephson junction arrays, predicting high directional amplification performance with current technology [3].

[1] Porras et al. PRL 122, 143901 (2019).

[2] Ramos et al. PRA 103, 033513 (2021).

[3] Ramos et al. arXiv:2207.13728 (2024).

[4] Gómez-León et al. Quantum 7, 1016 (2023).

[5] Rassaert et al. arXiv:2411.08965 (2024).

TBA

\abstract{Quantum correlations, particularly squeezing and entanglement, are essential in quantum technologies such as metrology, computation, and simulation, as well as in foundational studies. In quantum optics, these phenomena are often intertwined: two squeezed beams can be transformed into entangled beams by mixing them at a beam splitter, and vice versa. However, it is less common to encounter states where two beams are simultaneously squeezed individually while retaining global entanglement. These hybrid states evidently present potential possibilities for applications. In this work, we propose a compact single-cavity source based on a nondegenerate optical parametric oscillator operated below threshold, capable of generating such light—signal and idler beams that are quadrature-squeezed individually while maintaining global entanglement. This behavior arises from an additional linear coupling between the signal and idler, resembling a beam-splitter interaction. We discuss two physical implementations of this system: one based on intra-cavity electro-optic modulators and the other on optomechanical interactions. This unique combination of local and non-local quantum correlations opens the door to novel quantum communication and metrology protocols.}

We performed an experimental and numerical study of an Indium Phosphide photonic integrated circuit designed for quantum random number generation. We investigated the dynamics of two weakly mutually coupled semiconductor lasers and the transient evolution towards the synchronization of the lasers’ optical phases. The simulated dynamics with the experimentally adjusted parameters were found to be in qualitatively good agreement with the experimental time traces. The results provide a better understanding of the evolution towards synchronization and a foundation for the optimization of the photonic quantum random number generation system.