Abstract
This paper analyzes how UV/IR relations in AdS/CFT holography determine the behavior of degrees of freedom, thermal fluctuations, and entropy in the AdS bulk and its conformal field theory boundary. First, using a UV regulator δ on the AdS boundary, the expectation values of coordinate fluctuations behave as ⟨z⟩² ~ δ⁻² and ⟨y⟩² ~ δ². This demonstrates that the SYM UV cut off on the boundary maps to the IR cut-off inside the bulk. Considering a boundary patch of area 1, with 1/δ³ cutoff cells and N² degrees of freedom per cell (from the adjoint of U(N)), the total degrees of freedom per unit area becomes N_dof ≈ N²/δ³. The regulated 8-dimensional area scales as R⁸/δ³, giving N_dof/A ~ N²/R⁸. Using 1/G ~ N²/R⁸, this matches the holographic principle. Next, thermal fluctuations of the SYM field Φ satisfy ⟨Φ²⟩ = T²_SYM, replacing earlier UV fluctuation expressions. Thermal fluctuations become significant at z ~ T_SYM, corresponding to (1–r) ~ 1/T_SYM, similar to the AdS black hole horizon relation. Then i introduces the Sarkar Approximation, assuming the boundary cut-off δ is very small (close to Planck length), creating a quantum domain where degrees of freedom satisfy a “position–momentum” uncertainty relation r•p ~ ħ. Using r ≈ 1 – 1/T_SYM and E_SYM = cN²T⁴_SYM, one obtains: (T⁴_SYM – T³_SYM) c N_dof ≈ 1. Solving this differential relation yields: N_dof = eⁱ × (1 – T_SYM) / T³_SYM, where eⁱ is a dimensionless factor determined by physical limits. At T_SYM → ∞ (boundary), N_dof → 0 unless eⁱ → ∞.At T_SYM → 0 (bulk), N_dof → ∞ unless eⁱ → 0. Thus N_dof remains fixed in both regimes. Using S = |ln(N_dof)|, the entropy of the AdS boundary and the bulk are equal. This equality expresses a holographic limit, and equation (40) is termed the “Sarkar Equation of Holography.”
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