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Spin-squeezed Ground States in the Bilayer Quantum Hall Ferromagnet

T. Nakajima·H. Aoki
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Abstract

A "squeezed-vacuum" state considered in quantum optics is shown to be realized in the ground-state wavefunction for the bilayer quantum Hall system at the total Landau level filling of $ν=1/m$ (m: odd integer). This is derived in the boson approximation, where a particle-hole pair creation across the symmetric-antisymmetric gap, $Δ_{SAS}$, is regarded as a boson. In terms of the pseudospin describing the layers, the state is a spin-squeezed state, where the degree of squeezing is controlled by the layer separation and $Δ_{SAS}$. An exciton condensation, which amounts to a rotated spin-squeezed state, has a higher energy due to the degraded SU(2) symmetry for $Δ_{SAS} \neq 0$.

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T. Nakajima, H. Aoki. 1997-11-05. Spin-squeezed Ground States in the Bilayer Quantum Hall Ferromagnet. https://doi.org/10.1103/physrevb.56.r15549

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