Observation of PT-symmetric quantum interference

Klauck, Friederike; Teuber, Lucas; Ornigotti, Marco; Heinrich, Matthias; Scheel, Stefan; Szameit, Alexander

doi:10.1038/s41566-019-0517-0

Cited by 151 publications

(107 citation statements)

References 38 publications

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“…A class of Hamiltonians with PT-symmetry, which commute with the joint operation parity P and time-reversal operator T , was found to be able to keep the eigenvalues of H real in the exact PT phase [ 23 ]. Since then, PT quantum mechanics has been extensively investigated theoretically [ 24 , 25 , 26 , 27 , 28 , 29 , 30 , 31 , 32 , 33 , 34 , 35 , 36 , 37 , 38 , 39 , 40 , 41 , 42 , 43 , 44 ] and experimentally [ 12 , 13 , 14 , 45 , 46 , 47 , 48 ]. In fact, P -pseudo-Hermiticity was pointed out to be a sufficient and necessary condition to keep the spectrum of a non-Hermitian Hamiltonian purely real [ 49 , 50 , 51 ], and both the theory and applications are developed further [ 52 , 53 , 54 , 55 , 56 , 57 ].…”

Section: Introductionmentioning

confidence: 99%

Efficient Quantum Simulation of an Anti-P-Pseudo-Hermitian Two-Level System

Zheng

Tian

et al. 2020

Entropy

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Besides Hermitian systems, quantum simulation has become a strong tool to investigate non-Hermitian systems, such as PT-symmetric, anti-PT-symmetric, and pseudo-Hermitian systems. In this work, we theoretically investigate quantum simulation of an anti-P-pseudo-Hermitian two-level system in different dimensional Hilbert spaces. In an arbitrary phase, we find that six dimensions are the minimum to construct the anti-P-pseudo-Hermitian two-level subsystem, and it has a higher success probability than using eight dimensions. We find that the dimensions can be reduced further to four or two when the system is in the anti-PT-symmetric or Hermitian phase, respectively. Both qubit-qudit hybrid and pure-qubit systems are able to realize the simulation, enabling experimental implementations in the near future.

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Section: Introductionmentioning

confidence: 99%

Efficient Quantum Simulation of an Anti-P-Pseudo-Hermitian Two-Level System

Zheng

Tian

et al. 2020

Entropy

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“…However, recently efforts have been made to also investigate second-quantisation effects in non-Hermitian systems with one successful example being the measurement of two-photon Hong-Ou-Mandel correlations in a PTsymmetric waveguide coupler [12]. The key step was the use of passive PT symmetry meaning that the required antisymmetric gain/loss distribution was replaced by an all-loss distribution with the same antisymmetry.…”

Section: Introductionmentioning

confidence: 99%

Solving the quantum master equation of coupled harmonic oscillators with Lie-algebra methods

Teuber

Scheel

2020

Phys. Rev. A

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Based on a Liouville-space formulation of open systems, we present two methods to solve the quantum dynamics of coupled harmonic oscillators experiencing Markovian loss. Starting point is the quantum master equation in Liouville space which is generated by a Liouvillian that induces a Lie algebra. We show how this Lie algebra allows to define ladder operators that construct Fock-like eigenstates of the Liouvillian. These eigenstates are used to decompose the time-evolved density matrix and, together with the accompanying eigenvalues, provide insight into the transport properties of the lossy system. Additionally, a Wei-Norman expansion of the generated time evolution can be found by a structure analysis of the algebra. This structure analysis yields a construction principle to implement effective non-Hermitian Hamiltonians in lossy systems. arXiv:1912.07320v2 [quant-ph] 30 Jan 2020

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“…In the quantum domain, realization of systems governed by effective non-Hermitian Hamiltonians and exploration of the effect of exceptional points has only been possible very recently. Quantum non-Hermitian systems have been experimentally realized in linear optical circuits [60,61], quantum photonics [62], ultracold atoms [63,64], a diamond NV center [65], superconducting circuits [66,67], atom-light interacting systems [68], and a lossy quantum point contact [69]. However, all the realizations in the quantum regime are in cases where the overall system is dissipative.…”

Section: Introductionmentioning

confidence: 99%

Emergent PT symmetry in a double-quantum-dot circuit QED setup

Purkayastha

Kulkarni

Joglekar

2020

Phys. Rev. Research

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Open classical and quantum systems with effective parity-time (PT) symmetry, over the past five years, have shown tremendous promise for advances in lasers, sensing, and nonreciprocal devices. And yet, how such effective PT-symmetric non-Hermitian models emerge out of Hermitian quantum mechanics is not well understood. Here, starting from a fully Hermitian microscopic Hamiltonian description, we show that a non-Hermitian Hamiltonian emerges naturally in a double-quantum-dot (DQD) circuit-QED setup, which can be controllably tuned to the PT-symmetric point. This effective Hamiltonian governs the dynamics of two coupled circuit-QED cavities with a voltage-biased DQD in one of them. Our analysis also reveals the effect of quantum fluctuations on the PT-symmetric system. The PT transition is, then, observed both in the dynamics of cavity observables as well as via an input-output experiment. As a simple application of the PT transition in this setup, we show that loss-induced enhancement of amplification and lasing can be observed in the coupled cavities. By comparing our results with two conventional local Lindblad equations, we demonstrate the utility and limitations of the latter. Our results pave the way for an on-chip realization of a potentially scalable non-Hermitian system with a gain medium in the quantum regime, as well as its potential applications for quantum technology.

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Observation of PT-symmetric quantum interference

Cited by 151 publications

References 38 publications

Efficient Quantum Simulation of an Anti-P-Pseudo-Hermitian Two-Level System

Efficient Quantum Simulation of an Anti-P-Pseudo-Hermitian Two-Level System

Solving the quantum master equation of coupled harmonic oscillators with Lie-algebra methods

Emergent PT symmetry in a double-quantum-dot circuit QED setup

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