How do entanglement and spacetime interact in quantum gravity?

Quantum entanglement and the fabric of spacetime are increasingly seen as two aspects of the same underlying physics in approaches to quantum gravity. The AdS/CFT correspondence introduced by Juan Maldacena at the Institute for Advanced Study established a precise duality between a quantum field theory without gravity and a higher-dimensional gravitational spacetime. That correspondence created a laboratory in which entanglement in the boundary quantum theory translates into geometric properties in the bulk spacetime, suggesting that entanglement patterns can generate spatial connectivity.

Entanglement as a geometric ingredient

The Ryu-Takayanagi proposal formulated by Shinsei Ryu at University of Illinois Urbana-Champaign and Tadashi Takayanagi at University of Tokyo gave a concrete rule: the entanglement entropy of a region in the boundary field theory equals the area of a minimal surface in the bulk spacetime divided by four times Newton’s constant. This relation parallels the Bekenstein-Hawking formula for black hole entropy and supports the idea that area and therefore geometry can be read from quantum entanglement. Mark Van Raamsdonk at University of British Columbia argued that gradually reducing entanglement between two halves of a system causes the dual spacetime to pinch off, directly linking entanglement strength to geometric connectedness.

ER=EPR and the reconciliation of nonlocality

Juan Maldacena at the Institute for Advanced Study and Leonard Susskind at Stanford University proposed the ER=EPR conjecture, which identifies Einstein-Rosen bridges, or wormholes, with Einstein-Podolsky-Rosen entangled pairs. The conjecture is not a complete theory but it reframes apparent nonlocal correlations as spacetime structures, offering a conceptual path toward reconciling quantum nonlocality with relativistic causality. Daniel Harlow at Harvard University and others have developed complementary perspectives, interpreting aspects of the AdS/CFT mapping as a quantum error-correcting code: local bulk operators are redundantly encoded in entangled boundary degrees of freedom, making bulk geometry robust against local errors.

Causes and consequences for physics and society

The reason entanglement plays this role stems from the conflict between general relativity’s description of smooth geometry and quantum theory’s emphasis on entangled degrees of freedom. When gravity is weakly coupled, semiclassical geometry emerges; when quantum correlations are reorganized, the emergent geometry changes. Consequences include new approaches to the black hole information paradox, where entanglement structure determines how information is encoded and can potentially escape via subtle correlations rather than simple semiclassical evaporation. For cosmology, these ideas raise questions about how early-universe entanglement could influence large-scale spatial structure and whether holographic principles apply to de Sitter-like spacetimes relevant to our universe.

Human and cultural dimensions of this research are significant. Work is highly collaborative and international, with theorists at institutes and universities across continents exchanging ideas in seminars and preprints. Theoretical progress shapes graduate training in fundamental physics and informs public narratives about the unity of information and space. Environmentally, these inquiries are computational and conceptual rather than resource-intensive experiments, making them accessible to a wide range of institutions. Territorially, the concentration of expertise at particular research centers influences career pathways, but open publications and online seminars help distribute knowledge globally.

While many technical details remain unresolved, the convergence of entanglement measures, holography, and geometric reasoning provides a compelling and evidence-backed route toward understanding how quantum information can give rise to spacetime itself.