Quantum technologies are based on exploiting the principles of quantum mechanics to develop advanced devices such as quantum computers, communication systems, and sensors. To fully realize their potential, it is essential to achieve reliable transmission and exchange of quantum entanglement over long distances and between different qubit platforms. This enables secure quantum encryption, distributed quantum computing, and quantum-enhanced measurements. The central challenge is therefore to efficiently interconnect diverse quantum systems, such as atoms, ions, photons, superconducting qubits, NV centers, and optomechanical systems, despite the inherent fragility of quantum states.
At the Laboratory for Cold Atoms (ultracool.ijs.si), we develop atom-based quantum devices, including Rydberg quantum simulators, atomic quantum memories, magnetometers, and atomic clocks. At the Laboratory for Quantum Entanglement (entanglement.ijs.si), we develop sources of entangled photon pairs and advanced methods for entanglement distribution between remote locations for quantum communication applications. The collaboration between the two laboratories creates a strong research platform for the development of hybrid quantum devices.
The proposed program focuses on the development of quantum interfaces between different platforms and on the distribution of entanglement among them. The objective is to establish a hybrid quantum architecture in which atomic systems function as quantum memories and processors, photons serve as long-distance information carriers, and other platforms act as specialized building blocks for specific tasks. In collaboration with the Faculty of Mathematics and Physics at the University of Ljubljana, we will develop narrowband sources of entangled photons compatible with atomic transitions, together with atomic quantum memories for the storage of photonic quantum states. Particular emphasis will be placed on generating entanglement between different physical systems, for example between Rydberg atoms and ions, NV centers, or superconducting qubits via photonic or microwave links.
An important component of the program will be the development of quantum transducers between the microwave and optical domains, enabling the integration of superconducting qubits with optical communication networks. We will also investigate optomechanical and other nonlinear systems as potential converters between frequency domains. The long-term vision of the program is to demonstrate key elements of a quantum internet: storage, conversion, transmission, and distribution of quantum entanglement between heterogeneous nodes. The program represents a natural extension of existing research and an ambitious yet feasible step toward modular and interconnected quantum technologies of the future.