Quantum-resource advantages for broadband weak-signal searches

Determine whether and to what extent conventional, squeezed, entanglement-assisted, and non-Gaussian receivers provide different performance and resource scalings for broadband searches for weak stochastic signals, measured by discovery probability, localization error, scan bandwidth, and total integration time.

Background

The paper applies QΨ to experimentally motivated sensing of classical stochastic fields and discusses broadband searches for weak signals, including axion and gravitational-wave detection. These tasks involve more than estimating a single fixed parameter: the receiver may need to discover a signal, localize it, scan a bandwidth, and accumulate evidence over time.

The open problem is to compare receiver architectures—conventional, squeezed, entanglement-assisted, and non-Gaussian—under a common accounting of these application-level performance metrics and their associated experimental resources. The comparison is intended to establish when quantum-enhanced sensing yields a meaningful advantage beyond improvements in an isolated precision measure.

References

Several open problems in quantum sensing of classical fields admit natural formulations within our framework. In non-Gaussian noise spectroscopy, one may ask for the measurement complexity of estimating a selected higher-order correlation or polyspectral coefficient under constraints on pulse bandwidth, sensor coherence, and quantum memory [56, 57, 58]. In broadband searches for weak stochastic signals such as in axion or gravitational wave detection, one may compare conventional, squeezed, entanglement-assisted, and non-Gaussian receivers while measuring performance through discovery probability, localization error, scan bandwidth, and total integration time [59, 60, 61, 62].

— Exponential quantum advantage for learning signals with a single qubit  (2608.13521 - Kannan et al., 13 Aug 2026) in Appendix A.2, section “Quantum sensing”