{"artifact_id":"L1-911","layer":"L1","title":"Quantum Gravity — Emergent Spacetime from Entanglement","domain":"Quantum Gravity","sub_domain":"Holography","physics_fingerprint":{"intro":"General relativity and quantum mechanics disagree at the smallest scales. Holography (AdS/CFT, Ryu–Takayanagi: S(A)=Area/4G) suggests spacetime geometry emerges from quantum entanglement. Reconstructing the bulk from boundary entanglement tests whether gravity is emergent.","title":"Quantum Gravity — Emergent Spacetime from Entanglement","domain":"Quantum Gravity","chapter":"Ch.11 Physics & Cosmology","why_hard":"We lack direct experiments; toy models are the proving ground; bulk reconstruction is an ill-posed inverse problem constrained by subtle entanglement inequalities.","agent_idea":"An agent that, given a boundary state's entanglement data, proposes and scores candidate bulk geometries.","approaches":["Tensor-network and neural bulk reconstruction from boundary entanglement","Learning the RT surface / entanglement-wedge map","Testing reconstructions against known AdS duals"],"sub_domain":"Holography","forward_model":"Holographic entanglement entropy S(A)=Area(γ_A)/4G_N; reconstruct the bulk metric g_{μν} from boundary entanglement entropies of a CFT state.","benchmark_goal":"Reconstruct the bulk metric from boundary entanglement entropies with low geodesic-area error, respecting strong subadditivity.","challenge_blurb":"Reconstruct the geometry of spacetime from quantum entanglement — test whether gravity is emergent (Ryu–Takayanagi).","challenge_group":"physics","challenge_short":"Quantum Gravity","grand_challenge":true,"governing_equation":"S(A) = Area(γ_A) / 4 G_N  (Ryu–Takayanagi)"},"observable_profile":{"unit":"bulk-metric reconstruction error (lower better)","floor":0.1,"metric":"metric_recon_err","sota_reference":"Tensor-network / RT bulk reconstruction (AdS/CFT toy models)"},"size_tiers":{"bulk_depth":[4,8,16],"boundary_sites":[16,64,256]},"hardness_fn":{"type":"grand_challenge","metric":"metric_recon_err","baseline":"Linear RT inversion","delta_tier":50},"initiator_dataset":[{"name":"AdS/CFT tensor-network entanglement corpus","weight":0.6,"ipfs_cid":null,"license_hash":null},{"name":"Random-CFT entanglement-spectrum set","weight":0.4,"ipfs_cid":null,"license_hash":null}],"status":"testnet","staked_pwm":5000.0,"chain_hash":null,"chain_tx_hash":null,"chain_block":null,"wp":{},"plain_intro":"Quantum Gravity — Emergent Spacetime from Entanglement (Holography) is a problem in Quantum Gravity. The forward model maps the hidden the unknown quantity to a measurement. The inverse goal is to recover the the unknown quantity from the observed data."}