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Conformally invariant free-parafermionic quantum chains with multispin interactions.

Francisco C Alcaraz1, Lucas M Ramos1

  • 1Instituto de Física de São Carlos, Universidade de São Paulo, Caixa Postal 369, 13560-970, São Carlos, SP, Brazil.

Physical Review. E
|May 17, 2024
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Summary
This summary is machine-generated.

We studied non-Hermitian quantum chains with multispin interactions, finding distinct conformal phases based on boundary conditions. These models exhibit conformal invariance and a multicritical point.

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Area of Science:

  • Quantum physics
  • Condensed matter theory
  • Statistical mechanics

Background:

  • Non-Hermitian quantum systems offer a unique framework to explore complex phenomena beyond traditional Hermitian theories.
  • Multispin interactions in quantum chains introduce rich collective behaviors and symmetries.

Purpose of the Study:

  • To investigate the spectral properties and conformal invariance of two related families of non-Hermitian free-particle quantum chains with N-multispin interactions.
  • To analyze the influence of boundary conditions (open vs. periodic) on the physics of these non-Hermitian models.

Main Methods:

  • Calculation of spectral properties for Z(N) symmetric (parafermionic) and U(1) symmetric (fermionic) quantum chains.
  • Analysis of finite-size behavior of eigenspectra and entanglement properties of ground-state wave functions.
  • Comparison of models with open and periodic boundary conditions.

Main Results:

  • Both families of quantum chains share the same pseudo-energies forming their eigenspectra.
  • A multicritical point with a dynamical critical exponent z=1 was identified.
  • Finite-size scaling and entanglement data indicate conformal invariance for both model families.
  • Distinct physical behaviors and conformal phases emerge for open versus periodic boundary conditions due to non-Hermiticity.

Conclusions:

  • The studied non-Hermitian quantum chains exhibit rich physics, including conformal invariance and multicriticality.
  • Boundary conditions play a crucial role in determining the phase structure and conformal properties of these systems.
  • The Z(N) and U(1) symmetric models provide a versatile platform for exploring non-Hermitian quantum phenomena.