We propose a novel experimental protocol that positions an isolated, naturally asymmetric Fenna–Matthews–Olson (FMO) light-harvesting complex from the green sulfur bacterium Chlorobaculum tepidum at one slit of a single-photon double-slit interferometer. The FMO trimer harbours two energetically inequivalent branches—one possessing an additional bridging bacteriochlorophyll at site 8—constituting a physically realised, biologically native which-path detector. We measure fringe visibility V = (I max − Imin) / (I max + Imin) as a function of FMO coupling strength, temperature (4–310 K), and genetic modification state, seeking to determine whether native biological asymmetry is sufficient to induce wavefunction collapse selectively at one slit. Three mutually exclusive hypotheses are tested: full collapse (H1), no collapse (H2), and continuous visibility reduction proportional to coupling strength (H3). We further propose a genetic tunability programme—spanning bchQ/bchR deletion mutants, site-directed mutagenesis at BChl-binding residues, and synthetic chromophore incorporation—that transforms the experiment from a binary yes/no test into a quantitative dose–response curve mapping the genotype-to-collapse continuum. A comprehensive literature survey confirms that this specific three-way intersection of double-slit interferometry, FMO asymmetry, and biological which-path detection has never been proposed or executed. The closest precedents—strong coupling of living C. tepidum to optical microcavities (Coles et al. 2017), quantum discord proposals for photosynthetic organisms (Krisnanda et al. 2018), and gold-nanoparticle observer experiments (2024)—each address only one vertex of this triangle. This proposal addresses all three simultaneously for the first time.
Fransisko Alfredo Ikson Saputra (2026) studied this question.