<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:mrow> <mml:mi>P</mml:mi> <mml:mi>T</mml:mi> </mml:mrow> </mml:math> -symmetry phase transition in a bipartite lattice with long-range interactions

Abstract We investigate the parity–time ( <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"> <mml:mrow> <mml:mi mathvariant="script">P</mml:mi> <mml:mi mathvariant="script">T</mml:mi> </mml:mrow> </mml:math> ) symmetry-breaking quantum phase transition in a one-dimensional (1D) bosonic lattice featuring cavity-mediated long-range interactions and spatially staggered dissipation. By mapping the system to an effective spin chain under the constraints of hard-core bosons and integrating the mean-field decoupling approach with biorthogonal basis formalism, we derive a self-consistency equation. Numerical simulation results validate that the derived equation quantitatively captures the <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"> <mml:mrow> <mml:mi mathvariant="script">P</mml:mi> <mml:mi mathvariant="script">T</mml:mi> </mml:mrow> </mml:math> -symmetry order parameter’s phase diagram. Our findings reveal that coherent hopping maintains <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"> <mml:mrow> <mml:mi mathvariant="script">P</mml:mi> <mml:mi mathvariant="script">T</mml:mi> </mml:mrow> </mml:math> symmetry through quantum fluctuations. Conversely, cavity-engineered long-range interactions, in synergy with staggered dissipation, act in opposition to drive symmetry breaking. This competitive interplay can inspire further exploration of tunable quantum phase transitions in non-Hermitian systems.