The Biological Anchor: A Roadmap to Room-Temperature Quantum Communication by Co-opting Photosynthetic Coherence and De Novo Protein Design

The quest for a scalable quantum internet is fundamentally stalled by the repeater problem, a challenge rooted in the catastrophic fragility of quantum states (decoherence). Current state-of-the-art approaches, based on superconducting circuits, solid-state defects, or photonic memories, are trapped in a trilemma of impossible temperatures, manufacturing, or storage. This paper proposes a radical paradigm shift, abandoning the brute-force engineering of coherence in artificial systems and instead co-opting the principles of the only system known to have mastered it: biological life.Inspired by the long-lasting quantum coherence observed in photosynthetic complexes, we present an engineering roadmap for a room-temperature quantum repeater based on a hybrid bio-quantum architecture. Our "Biological Anchor" protocol leverages the power of de novo protein design to engineer a synthetic molecular "cage," whose excitonic resonance is precisely tuned to the telecommunications C-band wavelength of ~ 1550 nm. This biological "song" acts as a perfect quantum key, mediating the transfer of quantum information from a photon to a guest qubit—a single, shielded Erbium ion—harmonized at a quantum level.