Maximal quantum entanglement at exceptional points via unitary and thermal dynamics

Abstract

Minimal, open quantum systems that are governed by non-Hermitian Hamiltonians have been realized across multiple platforms in the past two years. Here we investigate the dynamics of open systems with Hermitian or anti-Hermitian Hamiltonians, both of which can be implemented in such platforms. For a single system subject to unitary and thermal dynamics in a periodic manner, we show that the corresponding Floquet Hamiltonian has a rich phase diagram with numerous exceptional-point (EP) degeneracy contours. This protocol can be used to realize a quantum Hatano-Nelson model that is characterized by asymmetric tunneling. For one unitary and one thermal qubit, we show that the concurrence is maximized at the EP that is controlled by the strength of Hermitian coupling between them. Surprisingly, the entropy of each qubit is also maximized at the EP. Our results point to the multifarious phenomenology of systems undergoing unitary and thermal dynamics.

8 pages, 3 figures

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• Making Sense of Non-Hermitian Hamiltonians
• Visualization of Branch Points in PT-Symmetric Waveguides
• Physical realization of $\mathcal{P}\mathcal{T}$-symmetric potential scattering in a planar slab waveguide
• Observation of parity-time symmetry breaking in a single spin system
• Real- and imaginary-time evolution with compressed quantum circuits
• PT spectroscopy of the Rabi problem
• Exceptional points of any order in a single, lossy, waveguide beamsplitter by photon-number-resolved detection
• Quantum information dynamics in a high-dimensional parity-time-symmetric system
• Observation of two PT transitions in an electric circuit with balanced gain and loss

Cited by in corpus (11)

• Speeding up entanglement generation by proximity to higher-order exceptional points
• Universal subdiffusive behavior at band edges from transfer matrix exceptional points
• On-demand Parity-Time symmetry in a lone oscillator through complex, synthetic gauge fields
• Accelerating multipartite entanglement generation in non-Hermitian superconducting qubits
• Quantum correlations in dissipative gain-loss systems across exceptional points
• Emergent Liouvillian exceptional points from exact principles
• Stability of time-periodic $\mathcal{P}\mathcal{T}$ and anti-$\mathcal{P}\mathcal{T}$-symmetric Hamiltonians with different periodicities
• Multitype entanglement dynamics induced by exceptional points
• Robustness of tripartite entangled states in passive PT-symmetric qubits
• Non-Hermiticity induced thermal entanglement phase transition
• Parity violating spectral dynamics of black holes in dynamical Chern-Simons gravity