[Paper Review] Breaking SUSY on the Horizon

T. Banks|ArXiv.org|Jun 13, 2002

Cosmology and Gravitation Theories14 citations

TL;DR

This paper proposes a heuristic mechanism for SUSY breaking in de Sitter space by linking the gravitino mass to the cosmological constant via horizon-level quantum effects. Using entropy area laws, R-symmetry, and a statistical model of degenerate horizon states, it derives a critical exponent of 1/4, suggesting m_{3/2} ∼ Λ^{1/4} in Planck units, consistent with TeV-scale superpartner masses under current cosmological bounds.

ABSTRACT

I present a heuristic calculation of the critical exponent relating the gravitino mass to the cosmological constant in a de Sitter universe. The ingredients for the calculation are the area law for entropy, an R symmetry of the low energy effective Lagrangian, and a crude picture of the degenerate levels of the cosmological horizon.

Motivation & Objective

• To explain the observed smallness of the cosmological constant and its connection to SUSY breaking in de Sitter space.
• To resolve the discrepancy between classical expectations (m_{3/2} ∼ Λ^{1/2}) and phenomenologically viable TeV-scale superpartner masses (m_{3/2} ∼ Λ^{1/4}).
• To develop a heuristic framework for quantum gravity effects in finite-state dS spacetime where conventional QFT fails.
• To argue that IR divergences in dS space may signal the true origin of SUSY breaking, rather than UV physics or black hole diagrams.

Proposed method

• Uses the area law for entropy to model the number of quantum states near the cosmological horizon.
• Applies an R-symmetry structure present in the low-energy effective Lagrangian of N=1 SUGRA.
• Constructs a statistical model of degenerate energy levels of the cosmological horizon, treating them as a finite-level system.
• Argues that the gravitino mass arises from horizon-scale quantum fluctuations, not from virtual black hole processes.
• Rejects black hole production/decay diagrams due to incoherence in reassembly of decay products across causally disconnected horizons.
• Proposes that IR divergences in dS space may signal the physical origin of the anomalous Λ^{1/4} scaling, rather than UV effects.

Experimental results

Research questions

• RQ1 Why does the gravitino mass scale as Λ^{1/4} rather than Λ^{1/2} in a quantum theory of de Sitter gravity?
• RQ2 Can the finite number of quantum states in asymptotically de Sitter space lead to a non-perturbative mechanism for SUSY breaking?
• RQ3 Is the IR divergence structure of dS space quantum field theory the true physical origin of the anomalous critical exponent?
• RQ4 How can a globally dS-invariant effective action describe local physics near a single observer’s horizon?
• RQ5 What role does cosmological complementarity play in connecting horizon-level states to the low-energy effective Lagrangian?

Key findings

• The critical exponent relating the gravitino mass to the cosmological constant is proposed to be 1/4, not 1/2, based on horizon entropy and R-symmetry.
• The scaling m_{3/2} ∼ Λ^{1/4} is consistent with TeV-scale superpartner masses when the cosmological constant is at the observed level.
• Virtual black hole processes are ruled out as a mechanism due to incoherent reassembly of decay products across causally disconnected regions.
• IR divergences in dS space may be the true physical signal of SUSY breaking, rather than UV effects or black hole diagrams.
• The finite number of states in dS space implies no exact observables, but low-energy effective field theory remains approximately valid for local processes.
• The effective action is globally dS-invariant, and particle masses are defined as coefficients in this gauge-invariant, non-perturbative action.