Scalable Universal Quantum Computing and Networking Using Continuous-Variable Entangled Photonic Graphs
Abstract
Optical qubits are a promising candidate for scalable universal quantum computing, and for all-photonic networked long-distance quantum communications which does not require quantum memories and quantum frequency conversion---the two most difficult technology pieces that keeps quantum technologies from scaling up. This is because of the relative ease of generating photons, mature fabrication of photonic circuits and low decoherence rates. Photons naturally encode the information in communications and sensing, and quantum processing in transceivers could yield revolutionary improvements to state of the art. This suggests that all of the quantum computing (a.k.a., processing) should be done in the photonic domain. However, almost all of the funded research on quantum computing and processor technologies in the US has focused on matter quantum systems, e.g., superconducting and trapped ion qubits. The reason is that the two most prominent architectures for optical quantum information processing-the discrete-variable (DV) dual-rail photonic qubits proposed by Knill-Laflamme-Milburn (KLM) and the continuous-variable (CV) proposal of Gottesman-Kitaev-Preskill (GKP)--suffer from essentially the same problem: entangling gates for universal quantum computing involve probabilisitic operations ( due to limitations of linear optics in DV, and the need for non-Gaussian operations in CV), rendering both schemes extremely resource inefficient. There has been a surge of recent development in both DV and CV cluster-model quantum computing, which gives new hope to all-photonic quantum processing. However, some key obstacles remain that need to be overcome before it becomes practical. In this STIR proposal, we address this challenge by developing a hybrid CV DV scheme for universal and scalable photonic quantum computing, which will only require currently available technology. To address our objective, we bring together a team of experts with complementary expertise: PI Prof. Saikat Guha-an expert in quantum optics, information theory and network theory, who has led various programs on photonic quantum information processing over the last decade; and Dr. Christos Gagatsos-an expert on CV entanglement theory, quantum geometry and topology, behavior of non-Gaussian states under probabilistic processes, and quantum estimation theory. Our proposed scheme for universal cluster state generation will only use experimentally existing large Gaussian (squeezed-state) cluster states, photon number detection, and homodyne detection. It will have wide applicability, and will be realizable using readily available technology. The success of this project will have tremendous impact not only in scalable realizability of quantum computing, but also in building long-distance quantum networks by realizing quantum router nodes that are equipped with photonic cluster-state entanglement sources, photon detectors, all-optical switches, and a classical computing and communication interface. The successful completion of this project will also have a huge impact on realizability of entanglement-assisted distributed sensing with applications ranging from LIGO, to distributed sensors for self-driving vehicle clusters to entanglement-assisted long-baseline astronomy.
Document Details
- Document Type
- DoD Grant Award
- Publication Date
- Feb 14, 2019
- Source ID
- W911NF1810377
Entities
People
- Saikat Guha
Organizations
- Army Contracting Command
- United States Army
- University of Arizona