Kavli Affiliate: Ke Wang
| First 5 Authors: Xin-Chi Zhou, Ke Wang, , ,
| Summary:
The critical point of a topological phase transition is described by a
conformal field theory (CFT), where the finite-size corrections to the ground
state energy are uniquely related to its central charge. We study the
finite-size scaling of the energy of non-Hermitian Su-Schrieffer-Heeger (SSH)
model with parity and time-reversal symmetry ($mathcal{PT}$) symmetry. We find
that under open boundary condition (OBC), the energy scaling $E(L)sim c/L$
reveals a negative central charge $c=-2$ at the non-Hermitian critical point,
indicative of a non-unitary CFT. Furthermore, we discover a universal scaling
function capturing the flow of a system from Dirac CFT with $c=1$ to a
non-unitary CFT with $c=-2$. The scaling function demonstrates distinct
behaviors at topologically non-trivial and trivial sides of critical points.
Notably, within the realm of topological criticality, the scaling function
exhibits an universal rise-dip-rise pattern, manifesting a characteristic
singularity inherent in the non-Hermitian topological critical points. The
analytic expression of the scaling function has been derived and is in good
agreement with the numerical results.
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