Holographic CCFT Pseudo-Entropy

Abstract: According to the flat/CCFT correspondence, Carrollian conformal field theories (CCFT) in d dimensions are dual to asymptotically flat spacetimes in d+1 dimensions. In this paper, starting from the holographic interpretation of pseudo-entropy in the (A)dS$_3$/CFT$_2$, we show that both extremal spacelike and timelike curves possess a well-defined flat-space limit. The length of these curves can be regarded as the real and imaginary parts of the pseudo-entropy for the underlying field theory, where only the real part has been considered thus far. Our calculations can confirm that the entanglement entropy in the CCFTs is fundamentally pseudo-entropy, and these theories are non-unitary.