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1 [1] (January 14, 2026)

handle is hein.crs/govetfh0001 and id is 1 raw text is: Defense Primer: Quantum Technology Quantum technology translates the principles of quantum physics into technological applications. Quantum technology has not yet reached maturity for most applications; however, it could hold significant implications for the future of military sensing, encryption, and communications, as well as for congressional oversight, authorizations, and appropriations. Key Concepts in Quantum Technology Quantum applications rely on a number of key concepts, including superposition, quantum bits (qubits), and entanglement. Superposition refers to the ability of quantum systems to exist in two or more states simultaneously. A qubit is a computing unit that leverages the principle of superposition to encode information. (A classical computer encodes information in bits that can represent binary states of either 0 or 1, whereas a quantum computer encodes information in qubits, each of which can represent 0, 1, or a combination of 0 and 1 at the same time. Thus, the power of a quantum computer increases exponentially with the addition of each qubit.) Entanglement is defined by the National Academy of Sciences (NAS) as a property in which two or more quantum objects in a system can be intrinsically linked such that measurement of one dictates the possible measurement outcomes for another, regardless of how far apart the two objects are. Entanglement underpins a number of potential military applications of quantum technology. Both superposition and entanglement are, however, difficult to sustain due to the fragility of quantum states, which can be disrupted by minute movements, changes in temperature, or other environmental factors. Miltary Appoications of Quanturm Technology The Defense Science Board (DSB), an independent Department of Defense (DOD) board of scientific advisors, has concluded that three applications of quantum technology hold the most promise for DOD: quantum sensing, quantum computers, and quantum communications. (DOD is currently using a secondary Department of War designation under Executive Order 14347 dated September 5, 2025.) The DSB concluded that quantum radar, hypothesized to be capable of identifying the performance characteristics (e.g., radar cross-section, speed) of objects-including low observable, or stealth, aircraft-will not provide upgraded capability to DOD. Quantum Sensing Quantum sensing uses the principles of quantum physics within a sensor. According to the DSB, this is the most mature military application of quantum technologies and is currently poised for mission use. Quantum sensing could provide a number of enhanced military capabilities. For example, it could provide alternative positioning, Updated January 14, 2026 navigation, and timing options that could in theory allow militaries to continue to operate at full performance in GPS-degraded or GPS-denied environments. In addition, quantum sensors could potentially be used in an intelligence, surveillance, and reconnaissance (ISR) role. Quantum sensors could enable military personnel to detect underground structures or nuclear materials due to their expected extreme sensitivity to environmental disturbances. The sensitivity of quantum sensors could similarly enable militaries to detect electromagnetic emissions, thus enhancing electronic warfare capabilities and potentially assisting in locating concealed adversary forces. On October 3, 2024, Senators Hassan and Blackburn submitted a formal letter to DOD requesting written responses-by November 15, 2024-to a series of questions about the Department's quantum sensing initiatives, funding, strategy, and coordination efforts. Quantum Computers According to NAS, quantum computers are the only known model for computing that could offer exponential speedup over today's computers. While quantum computers are in a relatively early stage of development (at least 10 years in the future, per DOD's July 2025 assessment), advances-many of which are driven by the commercial sector-could hold implications for the future of artificial intelligence (AI), encryption, and other disciplines. For example, some analysts have suggested that quantum computers could enable advances in machine learning, a subfield of Al. (For an explanation of Al- and machine learning-related terms, see CRS Infographic IG10077, Artificial Intelligence (AI) Taxonomy, by Laurie Harris and Nora Wells.) Such advances could spur improved pattern recognition and machine-based target identification. This could in turn enable the development of more accurate lethal autonomous weapon systems, or weapons capable of selecting and engaging targets without the need for manual human control or remote operation. Al-enabled quantum computers potentially could be paired with quantum sensors to further enhance military ISR applications. In addition, quantum computers could potentially decrypt classified or controlled unclassified information stored on encrypted media, allowing adversaries to gain access to sensitive information about U.S. military or intelligence operations. Some analysts note that significant advances in quantum computing would likely be required to break current encryption methods. Their estimates suggest that a quantum computer with around 20 million qubits would be required to break current encryption methods; however, the most advanced quantum computers today generally have no more than around 1,000 qubits.