Joint Parity-Time (PT) and Anti-Parity-Time (APT) Symmetric Qubits

One of the greatest obstacles to building large-scale quantum computers is the sensitivity of qubits to noise from their environment. This can shorten quantum computers' computational lifetime and lead to high error rates. A common way to mitigate this is by using quantum error correction, but this can be expensive in terms of qubit count. We suggest another approach, which is through incorporating non-Hermiticity with PT and APT symmetries into our qubits. We consider a PT and APT-symmetric two-level system coupled to a bosonic bath and present how to compute the dynamics and properties for these models by utilizing a time-dependent Dyson map for density matrices. We observe improved properties of decoherence, von Neumann entanglement entropy, and quantum Fisher information. This suggests that non-Hermitian PT and APT-symmetric qubits may be better suited for quantum computing and quantum information processing than conventional Hermitian qubits.