Kavli Affiliate: Zheng Zhu
| First 5 Authors: Guangyu Yu, Guangyu Yu, , ,
| Summary:
Deconfined quantum critical points (DQCPs) represent an unconventional class
of quantum criticality beyond the Landau-Ginzburg-Wilson-Fisher paradigm.
Nevertheless, both their theoretical identification and experimental
realization remain challenging. Here we report compelling evidence of a DQCP in
quantum Hall bilayers with half-filled $n=2$ Landau levels in each layer, based
on large-scale variational uniform matrix product state (VUMPS) simulations and
exact diagonalization (ED). By systematically analyzing the ground-state
fidelity, low-lying energy spectra, exciton superfluid and stripe order
parameters, and ground-state energy derivatives, we identify a direct and
continuous quantum phase transition between two distinct symmetry-breaking
phases by tuning the layer separation: an exciton superfluid phase with
spontaneous $U(1)$ symmetry breaking at small separation, and a unidirectional
charge density wave with broken translational symmetry at large separation. Our
results highlight quantum Hall bilayers as an ideal platform for realizing and
experimentally probing DQCPs under precisely tunable interactions.
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