EAGER: Creating Entangled Photonic Qubit Chip Based on Valleytronic Semiconductors

About This Grant

The project explores a novel type of compact all-solid-state entangled photon-emitting diode source, with the potential for ease of operation, high efficiency, and integration with other photonic and electronic quantum architectures. Compared with trapped ions, neutral atoms, and other quantum systems, photonic quantum devices usually present a much longer lifetime and information transmission distance; as such, they are considered promising candidates for the above-mentioned critical fields. However, today’s key challenge in photonic systems is that entangled photon sources have long suffered from low efficiency, complicated and bulky setups, sophisticated operation, and high maintenance costs. All these factors impede realizing the application of photonic quantum systems. This project is devoted to investigating advanced entangled light sources, leveraging recent breakthroughs in quantum materials, particularly valleytronic semiconductors and two-dimensional superconductors. The resulting source would generate quantum photon pairs in compact form, low cost, turnkey, and maintenance-free operation, very much like conventional light emitting diodes for mass use. The successful demonstration of such sources would drastically advance the development of photonic quantum sensing, communication, and computing networks, and accelerate their vast applications in scientific research, medicine, and national security. During the project period, a postdoctoral scholar and several graduate as well as undergraduate students will receive systematic training in quantum photonics, semiconductor physics, device fabrication technology, high-precision measurement, and beyond. The training from the project will cultivate the next-generation workforce for these critical quantum disciplines. The project will explore a newly conceived entangled photon-emitting diode (EPED), leveraging recent breakthroughs in quantum materials, particularly layered valleytronic semiconductors (LVS) and two-dimensional superconductors (2DSC). By constructing 2DSC-LVS tunneling junctions, the PIs plan to coherently inject entangled Ising electron pairs from 2DSC to LVS, and trigger photon pair emission with entanglement in polarization degree-of-freedom. To verify this concept, the project consists of three complementary tasks: (1) Quantum material synthesis, device fabrication, and fundamental characterization aiming at producing high-quality EPED; (2) Coincidence photon detection and quantum tomography measurement to determine the entanglement fidelity of EPED with various device configurations; (3) Investigation of disentanglement/decoherence mechanisms to identify physical factors, such as tunneling barrier materials and interfacial scattering, that could lead to decoherence. The studies in Tasks (2) and (3), in turn, will provide feedback on the material selection and device fabrication in Task (1) to help us verify the EPED function. This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.