Quantum-Enhanced Thermal Detection of Fundamental Limits and Mesoscopic Enhancement Mechanisms

We develop a comprehensive theoretical framework for quantum-enhanced thermal detection, establishing fundamental sensitivity limits through quantum estimation theory and analyzing enhancement mechanisms from squeezed state correlations and mesoscopic heat transfer phenomena. For detection at 10 μm wavelength against a 300 K background, we derive a modified Planck radiation law incorporating temperature gradient effects, calculate the quantum Fisher information for thermal state discrimination, and demonstrate that two-mode squeezed states in Type-II superlattice detectors provide up to cosh⁡(4𝑟) enhancement in temperature estimation precision, where 𝑟 is the squeezing parameter. We rigorously analyze background-limited performance and show that for a 0.1 m aperture system at 10 km range with 18% atmospheric transmission, the fundamental quantum limit for temperature resolution is 1.59 μK, while practical multi-pixel systems achieve 1.64 mK sensitivity with 48.8× improvement over classical systems. The analysis reveals that mesoscopic interface effects in composite materials provide up to 1.79× thermal contrast enhancement through ballistic phonon transport. This work establishes rigorous theoretical foundations for quantum-enhanced thermal imaging and identifies key physical limitations for lowcontrast target detection applications.