BROAD AGENCY ANNOUNCEMENT FOR Entangled Logical Qubits (ELQ) | W911NF 23 S 0004

Frequently Asked Questions (FAQs): Entangled Logical Qubits (ELQ) BAA (W911NF-23-S-0004)

1) What is the ELQ funding opportunity?

ELQ stands for "Entangled Logical Qubits." It is a Broad Agency Announcement (BAA) released by the Department of Defense (DoD) through the U.S. Army Materiel Command. The goal is to drive foundational research that moves quantum computing closer to universal, fault-tolerant operation by demonstrating fault-tolerant entanglement between two logical qubits and then using that entanglement to perform logical state teleportation.

2) What is the Funding Opportunity Number for ELQ?

The Funding Opportunity Number is W911NF-23-S-0004.

3) What core problem is ELQ trying to solve?

The opportunity targets a central barrier in quantum computing: physical qubits are highly sensitive to noise and environmental coupling, which causes errors and can destroy stored quantum information during computation. ELQ is focused on advancing beyond fragile physical-qubit behavior by working at the logical-qubit level, where quantum error correction (QEC) can detect and correct errors while preserving fault tolerance.

4) What is a logical qubit (LQ) in the context of this BAA?

A logical qubit is formed by combining many physical qubits using quantum error correction. The resulting logical qubit is designed to be more robust than any single physical qubit because it can detect and correct certain errors while maintaining fault tolerance.

5) What milestone is ELQ trying to reach beyond making one fault-tolerant logical qubit?

ELQ is aimed at the next major milestone: reliably entangling two separate, error-corrected logical qubits while keeping the entire process fault-tolerant end-to-end. This goes beyond demonstrating that a single logical qubit can be protected; it targets protected interactions between independently protected logical qubits.

6) What does the government mean by "fault-tolerant end-to-end" entanglement?

In this announcement, fault-tolerant end-to-end means error correction should remain effective across the entire entanglement workflow, including during the entangling operation itself. The DoD is not asking for entanglement that works only under idealized conditions; it is looking for an approach that avoids introducing new, uncontrolled error pathways that would undermine the value of logical qubits.

7) What is the overall duration and structure of the ELQ program?

The program is described as a four-year effort. It is divided into four phases (with additional details provided in the full announcement and referenced tables/sections). The sequencing is designed so that logical qubits are established earlier, with entanglement and teleportation demonstrated later, reinforcing a stepwise, end-to-end plan.

8) What specific technical demonstrations is ELQ seeking?

ELQ is looking for teams to design and experimentally demonstrate a complete operational sequence where two independently protected logical qubits are prepared, entangled through an operation that remains fault-tolerant, verified and benchmarked at the logical level, and then used to teleport a logical quantum state with high success.

9) Why does the BAA emphasize teleportation?

Teleportation is emphasized because it is a clean, widely recognized way to show that entanglement is not only present but usable for computation. In other words, teleportation serves as a strong proof that the entanglement between logical qubits is functional at the logical layer, not just a delicate physics effect observed at the physical layer.

10) What performance targets are mentioned in the opportunity?

The opportunity describes an ambitious but concrete target: demonstrations consistent with maximally entangled logical states and logical state teleportation success rates on the order of 95% or higher. The emphasis is that performance should be meaningful at the logical level, not merely at the underlying physical-qubit level.

11) Is the BAA asking only for entanglement, or for something more?

It is asking for more than simply producing entanglement. The announcement stresses preserving fault tolerance throughout the entanglement procedure, including how gates are implemented, how syndrome information is measured and processed, how correlated errors are prevented or detected, and how the system is validated via appropriate logical-level benchmarking and success metrics.

12) What does "modularity" mean in ELQ?

Modularity is a key requirement. ELQ is looking for approaches where the entangled pair is constructed from two decoupled, independently operable logical qubits on the same physical platform, and where the system can be separated back into those independent modules. This is intended to support scalability and robust system engineering.

13) Does ELQ require the two logical qubits to be independently functional before entanglement?

Yes. The program design sequences the work so that logical qubits are established in earlier years before proceeding to the entangling stage later. This effectively forces teams to show that each logical qubit works on its own before claiming success with entanglement between them.

14) Are proposals expected to address the full program or can they focus on a subset?

The BAA signals strongly that proposals should cover all four phases. Submissions addressing only a subset of phases may not receive full consideration, which is a common BAA approach to encourage end-to-end plans rather than isolated demonstrations.

15) What kinds of research activities does ELQ anticipate?

The anticipated work spans multiple layers of the quantum stack, including hardware development and control, software and compilation considerations, design and implementation of QEC protocols suited to logical entanglement, and rigorous benchmarking methods to quantify logical-level performance and fault-tolerance claims.

16) What is meant by "benchmarking at the logical level"?

Based on the description, logical-level benchmarking refers to validating performance and success metrics in terms of the logical qubits and logical operations (including the entangling operation and teleportation), rather than reporting only physical-qubit metrics. The intent is to substantiate fault-tolerance claims where it matters for scalable computation: at the logical layer.

17) Why does the announcement say this area is still a frontier?

The BAA states there is limited existing theory and comparatively little experimental precedent for fully fault-tolerant entanglement between separate logical qubits. As a result, proposals are expected to push both theory and practice forward in a coordinated way.

18) What types of teams does the government expect to be competitive for ELQ?

The announcement explicitly indicates likely winning teams will be interdisciplinary and comfortable working at interfaces between theory, experimental physics/engineering, control systems, and error-correction/verification.

19) What agency and organization are associated with this BAA?

The Department of Defense is the sponsor, and the announcement is released through the U.S. Army Materiel Command.

20) What is the funding opportunity category and activity type?

Administratively, the opportunity is categorized as discretionary. The activity category is science and technology and other research and development, consistent with the foundational R&D focus described in the announcement.

21) What award instrument types are mentioned?

The BAA allows multiple award instrument types, including cooperative agreements, grants, other transaction-like mechanisms (as applicable), and procurement contracts. This provides the government flexibility in how it partners with performers.

22) How many awards are expected?

The listing indicates an expected number of awards of up to 100.

23) Is there an award ceiling listed?

The award ceiling is shown as 0 in the summary data, which typically indicates the ceiling is not specified in that summary field and is instead addressed in the full BAA or negotiated per award.

24) What were the posted dates for this opportunity?

The opportunity was created on January 23, 2023. The original closing date is listed as March 21, 2023, at 4:00 PM Eastern Time.

25) Where should applicants look for eligibility and submission requirements?

The listing instructs applicants to consult the solicitation for submission rules and details on eligibility. The eligibility line points to an additional information field in the full text, indicating the definitive requirements are in the complete announcement.

26) What does success look like according to the ELQ description?

Success is framed as a system-level, modular, logically benchmarked demonstration: two independently functioning error-corrected logical qubits that can be entangled with high fidelity while preserving fault tolerance throughout, and that can prove usefulness via high-success logical state teleportation (with a stated target around 95% or higher).

27) Is ELQ focused on incremental qubit improvements or system-level capability?

The announcement describes ELQ as more than incremental improvements in qubit quality. It is aimed at a credible building block for scalable, universal fault-tolerant quantum computing by connecting QEC theory, experimental implementation, and validation into a repeatable approach that could eventually scale to larger architectures.