Quantum Computing (QC) has the potential to transcend the classical boundaries of computing in applications of interest to the Intelligence Community (IC) and the DoD. Qubits – the indivisible units or “bits” of quantum information in a quantum computer – exhibit quantum coherence[1] and entanglement[2],[3] but are also subject to noise and couplings with the environment, which weaken the coherence and lead to the loss of quantum information during the calculation and thus produce calculation errors. Fortunately, qubits can be organized into computational units called logical qubits (LQs) that work to preserve quantum information and coherence by detecting errors within their bounds, identifying corrections, and admitting repairs, while maintaining tolerance. to breakdowns. Theoretical and experimental advances in quantum error correction2 (QEC) have led to several demonstrations of fault-tolerant (FT) logic qubits in recent years on different hardware platforms. However, an additional step towards universal and fault-tolerant quantum computing2 (UFTQC) is to engage separate LQs in the entanglement, while maintaining consistency and fault-tolerance protections.
Entangled Logical Qubits (ELQ) is a four-year fundamental research program aimed at generating a high-fidelity entanglement between two error-corrected LQs in a fully FT fashion, and using it to achieve logic-state teleportation with a large hit. These achievements will lay the cornerstone for realizing the full potential of CQ and will make a profound step forward on the path of UFTQC. The program is divided into four (4) phases, described in Table 1, Table 2 and Table 4, and detailed in Section A. Proposals covering all four phases are invited under this BAA; proposals covering less may not be fully considered.
Generally speaking, ELQ seeks to develop and demonstrate schemes that preserve FT properties throughout an operational sequence that incorporates LQ entanglement. Importantly, the schemes must also exhibit modularity, where the entangled set is built from, and separable into, decoupled and independently functioning LQs residing on the same physical platform. Modularity is also enhanced by the structure of the program, with QLs being established separately during the first to third year of the program before proceeding with the entanglement operations. We define modularity in Section A.2.1.2 and Box A in relation to architectural requirements.
Although there is limited theoretical work, FT logical entanglement from the engagement of separate LQs is a frontier topic providing new ground for theory and practice to meet, cooperate and evolve towards a goal essential to the UFTQC. Achieving maximum high-fidelity and entangled logic states, as evidenced by, for example, teleportation success rates3 of 95% or more, is an ambitious but achievable goal given the continued advances in cutting-edge performance of quantum hardware and associated controls. The challenges – spanning developments of hardware, software, QEC protocols, benchmarking protocols – awaiting this deeper excursion into QC will be considerable. The teams selected will be interdisciplinary, able to work at the interfaces between the disciplines involved and capable of obtaining revolutionary results.
Learn more at SAM.gov