Dual opposing quadrature-PT symmetry

TL;DR

This paper explores dual opposing quadrature PT symmetry using a lossless type-II scheme, revealing new insights into quantum noise, C2Q transitions, and connections between PT symmetry and nonclassicality in continuous-variable systems.

Contribution

It introduces a lossless type-II PSA-only scheme for dual opposing quadrature PT symmetry, expanding understanding of C2Q transitions and quantum entanglement.

Findings

Demonstrates dual opposing quadrature PT symmetry in a lossless system

Reveals new C2Q transitions in quadrature and noise fluctuations

Uncovers links between PT symmetry, nonclassicality, and entanglement

Abstract

Our recent research on type-I quadrature parity-time (PT) symmetry, utilizing an open twin-beam system, not only enables observing genuine quantum photonic PT symmetry amid phase-sensitive amplification (PSA) and loss in the presence of Langevin noise but also reveals additional classical-to-quantum (C2Q) transitions in quadrature and relative-intensity noise fluctuations. In contrast to the previous setup, our exploration of an alternative system assuming no loss involves a type-II PSA-only scheme. This scheme facilitates dual opposing quadrature PT symmetry, offering a comprehensive and complementary comprehension of C2Q transitions and anti-Hermiticity-enhanced quantum sensing. Furthermore, our investigation into the correlation with the Einstein-Podolsky-Rosen criteria uncovers previously unexplored connections between PT symmetry and nonclassicality, as well as quantum entanglement within the continuous-variable framework.