The Quantum Benchmark Act directs the Secretary of Defense to establish a comprehensive policy within 180 days to guide how the Department of Defense develops and acquires quantum computing systems. The policy must define what constitutes a quantum computing system, create a process for validating and verifying these systems before they are developed or purchased, and align with the Defense Advanced Research Projects Agency's Quantum Benchmarking Initiative. Once the policy is issued, the Department cannot develop or acquire quantum computing systems unless they have been validated and verified under this new framework, though the Secretary of Defense can grant case-by-case waivers for specific systems. Any waiver granted must be reported to congressional defense committees within 15 days along with written justification. This legislation affects the Department of Defense and its various military and civilian elements that work with quantum computing technology, though no specific funding amount is mentioned in the bill.