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The emergent gravity viewpoint posits that gravitational phenomena arise as macroscopic manifestations of deeper quantum or thermodynamic processes rather than standing as an independent fundamental force. This perspective challenges traditional interpretations of general relativity by suggesting that gravity is not a primary interaction but an emergent feature of more basic physical principles. Proponents, including prominent theoretical physicists, argue that this framework could resolve longstanding puzzles in cosmology, astrophysics, and high-energy physics while offering a unified understanding of spacetime itself. Emergent gravity theories draw from diverse fields such as quantum information theory, black hole thermodynamics, and the holographic principle to construct models where gravitational effects emerge from entanglement, entropy, or other non-gravitational dynamics.

- The viewpoint that gravity can emerge from underlying quantum or thermodynamic effects rather than being a fundamental force - Advocated by some theoretical physicists exploring alternatives to general relativity - Scope: Primarily in cosmology, astrophysics, and high-energy physics

Advocates of emergent gravity contend that gravitational forces are not fundamental but instead emerge from entanglement entropy in quantum systems. This idea is closely linked to the AdS/CFT correspondence, which suggests a duality between gravitational theories in anti-de Sitter space and conformal field theories on their boundaries. In this framework, gravity arises as an effective description of how information is encoded across these boundaries, with entanglement playing a crucial role.

A key thermodynamic argument for emergent gravity stems from the Bekenstein-Hawking entropy formula, which relates black hole entropy to horizon area. Proponents argue that this suggests a deep connection between gravity and thermodynamics, where gravitational fields behave like emergent properties of underlying statistical mechanics. Ted Jacobson's work on this topic formalizes how near-horizon thermodynamics can reproduce Einstein's field equations, implying that gravity may be understood as an entropic force.

Emergent gravity also offers explanations for dark energy and cosmic acceleration without invoking exotic fields or fine-tuned parameters. Some models propose that the observed accelerated expansion of the universe arises from coarse-graining over microscopic quantum degrees of freedom, with no need for a separate cosmological constant. This aligns with efforts to derive macroscopic phenomena from more fundamental principles.

Another strength of emergent gravity is its potential to resolve black hole singularities and the information paradox. By treating spacetime as an emergent structure, these theories avoid classical singularities and suggest that information is preserved in quantum corrections or boundary effects. The holographic principle, which posits that all physical processes can be encoded on a lower-dimensional boundary, plays a central role in this context.

While proponents share the core idea of emergent gravity, distinct approaches exist with varying mechanisms and levels of empirical support. For example, Verlinde's entropic gravity proposal differs from AdS/CFT-based emergent spacetime models in its reliance on entropy gradients rather than holographic duality. Some researchers highlight tensions between these frameworks, particularly regarding their applicability beyond specific regimes or interpretational differences about the role of quantum entanglement.

Erik Verlinde proposed entropic gravity as an alternative to general relativity, arguing that gravitational attraction arises from changes in entropy when matter moves. Ted Jacobson linked thermodynamics and gravity through his derivation of Einstein's equations from thermodynamic principles near black hole horizons. Leonard Susskind and Gerard 't Hooft are key proponents of the holographic principle, which underpins many emergent gravity models. Raphael Bousso contributed to the holographic entropy bound, while Juan Maldacena developed the AdS/CFT correspondence, providing a concrete realization of emergent spacetime.

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1. Ted Jacobson, “Thermodynamics of Spacetime: The Einstein Equation of State,” *Physical Review Letters* 74, no. 7 (1995): 1062-1065. 2. Erik P. Verlinde, “On the Origin of Gravity and the Laws of Newton,” *Journal of High Energy Physics* 2010, no. 3 (2010): 041. 3. Leonard Susskind, *The Black Hole War: My Battle with Stephen Hawking to Unveil the Universe* (New York: Little, Brown and Company, 2008). 4. Raphael Bousso, “The Holographic Principle,” Reviews of Modern Physics 74 (2002): 125.