Quantum Zeno effect and nonclassicality in a 
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-symmetric system of coupled cavities

Naikoo, Javid; Thapliyal, Kishore; Banerjee, Subhashish; Pathak, Anirban

doi:10.1103/physreva.99.023820

Cited by 27 publications

(27 citation statements)

References 94 publications

(83 reference statements)

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“…Therefore, it is still an unresolved question how to formally define PT -symmetry for dissipative quantum systems [32] and if the breaking of this symmetry can exist at all at a microscopic level [31]. In several previous studies this question has been addressed by looking at coupled quantum oscillators [17,[28][29][30][31][34][35][36][37][38][39] or bosonic atoms [40] with gain and loss, or at equivalent coherent, but unstable systems [41]. In such settings, the symmetry-breaking effect can still be observed in the dynamics of the mean amplitudes, which simply reproduce the classical equations of motion, while quantum effects lead to increased fluctuations.…”

Section: Introductionmentioning

confidence: 99%

Emergence of PT-symmetry breaking in open quantum systems

et al. 2020

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The effect of \mathcal{PT}𝒫𝒯-symmetry breaking in coupled systems with balanced gain and loss has recently attracted considerable attention and has been demonstrated in various photonic, electrical and mechanical systems in the classical regime. However, it is still an unsolved problem how to generalize the concept of \mathcal{PT}𝒫𝒯 symmetry to the quantum domain, where the conventional definition in terms of non-Hermitian Hamiltonians is not applicable. Here we introduce a symmetry relation for Liouville operators that describe the dissipative evolution of arbitrary open quantum systems. Specifically, we show that the invariance of the Liouvillian under this symmetry transformation implies the existence of stationary states with preserved and broken parity symmetry. As the dimension of the Hilbert space grows, the transition between these two limiting phases becomes increasingly sharp and the classically expected \mathcal{PT}𝒫𝒯-symmetry breaking transition is recovered. This quantum-to-classical correspondence allows us to establish a common theoretical framework to identify and accurately describe \mathcal{PT}𝒫𝒯-symmetry breaking effects in a large variety of physical systems, operated both in the classical and quantum regimes.

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Section: Introductionmentioning

confidence: 99%

Emergence of PT-symmetry breaking in open quantum systems

et al. 2020

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“…Therefore, it is still an unresolved question how to formally define PT -symmetry for dissipative quantum systems [33] and if the breaking of this symmetry can exist at all at a microscopic level [32]. In several previous studies this question has been addressed by looking at coupled quantum oscillators [17,[29][30][31][32][34][35][36][37][38][39] or bosonic atoms [40] with gain and loss, or at equivalent coherent, but unstable systems [41]. In such settings, the symmetry-breaking effect can still be observed in the dynamics of the mean amplitudes, which simply reproduce the classical equations of motion, while quantum effects lead to increased fluctuations.…”

Section: Introductionmentioning

confidence: 99%

Report on scipost_202008_00009v1

2020

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The effect of PT-symmetry breaking in coupled systems with balanced gain and loss has recently attracted considerable attention and has been demonstrated in various photonic, electrical and mechanical systems in the classical regime. However, it is still an unsolved problem how to generalize the concept of PT symmetry to the quantum domain, where the conventional definition in terms of non-Hermitian Hamiltonians is not applicable. Here we introduce a symmetry relation for Liouville operators that describe the dissipative evolution of arbitrary open quantum systems. Specifically, we show that the invariance of the Liouvillian under this symmetry transformation implies the existence of stationary states with preserved and broken parity symmetry. As the dimension of the Hilbert space grows, the transition between these two limiting phases becomes increasingly sharp and the classically expected PTsymmetry breaking transition is recovered. This quantum-to-classical correspondence allows us to establish a common theoretical framework to identify and accurately describe PT-symmetry breaking effects in a large variety of physical systems, operated both in the classical and quantum regimes. B Fully symmetric steady state 11 C Random jump operators 12 References 13

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“…Strong effective nonlinear interactions can then be used to support the generation of nonclassical light [33,34]. Moreover, other purely quantum effects have been predicted in quantum PT -symmetric systems including the generation of en-tanglement [39] and the quantum Zeno effect [40]. Also their application in quantum-information processing has been discussed in Ref.…”

Section: Introductionmentioning

confidence: 99%

Nonclassical light at exceptional points of a quantum PT -symmetric two-mode system

et al. 2019

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A two-mode optical parity-time (PT ) symmetric system, with gain and damping, described by a quantum quadratic Hamiltonian with additional small Kerr-like nonlinear terms, is analyzed from the point of view of nonclassical-light generation. Two kinds of stationary states with different types of (in)stability are revealed. Properties of one of these are related to the presence of semiclassical exceptional points, i.e., exotic degeneracies of the non-Hermitian Hamiltonian describing the studied system without quantum jumps. The evolution of the logarithmic negativity, principal squeezing variances, and sub-shot-noise photon-number correlations, considered as entanglement and nonclassicality quantifiers, is analyzed in the approximation of linear-operator corrections to the classical solution. Suitable conditions for nonclassical-light generation are identified in the oscillatory regime, especially at and around exceptional points that considerably enhance the nonlinear interaction and, thus, the non-classicality of the generated light. The role of quantum fluctuations, inevitably accompanying attenuation and amplification in the evolution of quantum states, is elucidated. The evolution of the system is analyzed for different initial conditions.

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Quantum Zeno effect and nonclassicality in a PT -symmetric system of coupled cavities

Cited by 27 publications

References 94 publications

Emergence of PT-symmetry breaking in open quantum systems

Emergence of PT-symmetry breaking in open quantum systems

Report on scipost_202008_00009v1

Nonclassical light at exceptional points of a quantum PT -symmetric two-mode system

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