TY - JOUR
T1 - Continuous Phase Transition without Gap Closing in Non-Hermitian Quantum Many-Body Systems
AU - Matsumoto, Norifumi
AU - Kawabata, Kohei
AU - Ashida, Yuto
AU - Furukawa, Shunsuke
AU - Ueda, Masahito
N1 - Publisher Copyright:
© 2020 American Physical Society.
PY - 2020/12/21
Y1 - 2020/12/21
N2 - Contrary to the conventional wisdom in Hermitian systems, a continuous quantum phase transition between gapped phases is shown to occur without closing the energy gap Δ in non-Hermitian quantum many-body systems. Here, the relevant length scale ζ≃vLR/Δ diverges because of the breakdown of the Lieb-Robinson bound on the velocity (i.e., unboundedness of vLR) rather than vanishing of the energy gap Δ. The susceptibility to a change in the system parameter exhibits a singularity due to nonorthogonality of eigenstates. As an illustrative example, we present an exactly solvable model by generalizing Kitaev's toric-code model to a non-Hermitian regime.
AB - Contrary to the conventional wisdom in Hermitian systems, a continuous quantum phase transition between gapped phases is shown to occur without closing the energy gap Δ in non-Hermitian quantum many-body systems. Here, the relevant length scale ζ≃vLR/Δ diverges because of the breakdown of the Lieb-Robinson bound on the velocity (i.e., unboundedness of vLR) rather than vanishing of the energy gap Δ. The susceptibility to a change in the system parameter exhibits a singularity due to nonorthogonality of eigenstates. As an illustrative example, we present an exactly solvable model by generalizing Kitaev's toric-code model to a non-Hermitian regime.
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U2 - 10.1103/PhysRevLett.125.260601
DO - 10.1103/PhysRevLett.125.260601
M3 - Article
C2 - 33449745
AN - SCOPUS:85099117266
SN - 0031-9007
VL - 125
JO - Physical review letters
JF - Physical review letters
IS - 26
M1 - 260601
ER -