Because Trρk+1 are the moments of a probability measure on the unit interval, Hausdorff’s theorem makes complete monotonicity a complete criterion for a set of R ́enyi entropies to be the spectrum of a density matrix. Applied to the minimal-cut prescription of random tensor networks and monitored circuits, the criterion fails at a threshold with no free parameters: the sequence is a spectrum if and only if the competing cuts cross at R ́enyi index at most two, that is, when the multiplicity ratio does not exceed the bond dimension raised to the area difference. The obstruction is exact, and at small bond dimension it lies at a difference order below one hundred, so it is exhibitable by direct computation rather than only provable.
We show that Renyi entropies satisfy an area law in quantum field theories with a holographic dual description in terms of a bulk gravitational theory. A derivative of the Renyi entropy
Sn with respect to its index
n is given by the area in Planck units of a bulk cosmic brane homologous to the entangling region. This geometric prescription for holographic Renyi entropies is a one-parameter generalization of the Ryu-Takayanagi prescription for entanglement entropy. As an example of applying this prescription, we calculate the mutual Renyi information
In between two disks to linear order in
n−1 in holographic conformal field theories of arbitrary dimension.
A bstract We study Renyi entropies S n in quantum error correcting codes and compare the answer to the cosmic brane prescription for computing
S~n≡n2∂n(nn−1Sn) S ˜ n ≡ n 2 ∂ n n − 1 n S n . We find that general operator algebra codes have a similar, more general prescription. Notably, for the AdS/CFT code to match the specific cosmic brane prescription, the code must have maximal entanglement within eigenspaces of the area operator. This gives us an improved definition of the area operator, and establishes a stronger connection between the Ryu-Takayanagi area term and the edge modes in lattice gauge theory. We also propose a new interpretation of existing holographic tensor networks as area eigenstates instead of smooth geometries. This interpretation would explain why tensor networks have historically had trouble modeling the Renyi entropy spectrum of holographic CFTs, and it suggests a method to construct holographic networks with the correct spectrum.