A Non-Invasive Quantum Brain–Computer Interface and Cognitive Exoskeleton: Architecture, Physical Limits, and Roadmap

Given the rapid and potentially hazardous development of brain-computer interfaces, humans are highly susceptible to becoming "meat machines," with their privacy severely compromised. This paper presents an integrated wearable closed-loop architecture that combines quantum magnetic readout, focused ultrasound neuromodulation, and quantum-encrypted transmission, and systematically demonstrates its physical feasibility and engineering boundaries. Constrained by the metabolic energy costs of long-term potentiation (LTP), the system supports a controlled knowledge-injection payload of 1–2 MB per day. The architecture integrates chip-scale SERF optically pumped magnetometers (OPMs), transcranial focused ultrasound (tFUS), semantic latent space alignment via contrastive learning, and satellite-based quantum key distribution (QKD), enabling sensory augmentation and knowledge infusion while preserving cognitive sovereignty. We systematically analyze the relevant physical and neuroscientific foundations, quantify physical limits including channel capacity, spatial resolution, and energy constraints, and propose a phased engineering roadmap. Our results demonstrate that, within current technological boundaries, a non-invasive pathway can achieve controlled cognitive augmentation at a payload of 1–2 MB/day through semantic compression and an intent-gating protocol, while avoiding the long-term biocompatibility and ethical risks associated with invasive implants.