Ground state excitation of an atom strongly coupled to a free quantum field

Hsiang, Jen‐Tsung; Hu, B. L.

doi:10.1103/physrevd.100.125019

Cited by 6 publications

(3 citation statements)

References 111 publications

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“…Using the perturbative method, we find that the leading contribution to the time evolution of the n-coherent information occurs at second order for all n. Moreover, we show that to second order, the evolution of the n-coherent information is independent of the free Hamiltonians of either subsystem. This markedly simplifies the computations, and implies that complicated resonance phenomena do not affect the leading order behaviour of the coherent information, since such phenomena necessarily involve the free Hamiltonians in their mathematical descriptions [16,17].…”

Section: Introductionmentioning

confidence: 99%

Transmission of coherent information at the onset of interactions

Kendall¹,

Šoda²,

Kempf³

2022

J. Phys. A: Math. Theor.

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In this work, we investigate the parameters governing the rate at which a quantum channel arises at the onset of an interaction between two systems, A and B. In particular, when system A is pre-entangled with an ancilla, ̃A, we quantify the early-time transmission of pre-existing entanglement by calculating the leading order change in coherent information of the complementary channel (A → B′). We show that, when A and B are initially unentangled and B is pure, there is no change in coherent information to first order, while the leading (second) order change is divergent. However, this divergence may be regulated by embedding the conventional notion of coherent information into what we call the family of n-coherent informations, defined using n-R ́enyi entropies. We find that the rate of change of the n-coherent information at the onset of the interaction is governed by a quantity, which we call the n-exposure, which captures the extent to which the initial coherent information of A with ̃A is exposed to or ‘seen by’ the interaction Hamiltonian between A and B. We give examples in qubit systems and in the light-matter interaction.

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Section: Introductionmentioning

confidence: 99%

Transmission of coherent information at the onset of interactions

Kendall¹,

Šoda²,

Kempf³

2022

J. Phys. A: Math. Theor.

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“…The reduced density operator of a free harmonic oscillator linearly coupled with a scalar field bath has been derived before [4,25,26]. The corresponding reduced density operator for the driven harmonic oscillator can be formally obtained in the same manner,…”

Section: Driven Harmonic Oscillatormentioning

confidence: 99%

Nonequilibrium Nonlinear Open Quantum Systems I. Functional Perturbative Analysis of a Weakly Anharmonic Oscillator

Hsiang,

2019

Preprint

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We introduce a functional perturbative method for treating weakly nonlinear systems such as a chain of coupled quantum oscillators with own baths. We demonstrate using this method to obtain the correlation functions of a quantum anharmonic oscillator interacting with a heat bath. These results are useful for studying the nonequilibrium physical processes of nonlinear quantum systems such as heat transfer or electron transport.

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“…Research in the last two decades has spawned profound questions about radiative corrections and the issue of the correct gauge-invariant description of the dynamics of artificial atoms in solid-state electromagnetic media. These questions are fueled in part by engineered superconducting electrodynamical systems that feature some of the strongest interactions between light and matter ever achieved in physics [2,3], opening up exciting possibilities for applications in quantum information processing [4][5][6][7] while radically modifying various quantum optical phenomena, e.g., Purcell effect [8], Dicke physics [9], and ground state properties of atoms and the vacuum field [4,[10][11][12].…”

Section: Introductionmentioning

confidence: 99%

Radiative Properties of an Artificial Atom coupled to a Josephson Junction Array

Sinha,

Khan,

Cüce

et al. 2022

Preprint

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We study the radiative properties-the Lamb shift, Purcell decay rate and the spontaneous emission dynamics-of an artificial atom coupled to a long, multimode cavity formed by an array of Josephson junctions. Introducing a tunable coupling element between the atom and the array, we demonstrate that such a system can exhibit a crossover from a perturbative to non-perturbative regime of light-matter interaction as one strengthens the coupling between the atom and the Josephson junction array (JJA). As a consequence, the concept of spontaneous emission as the occupation of the local atomic site being governed by a single complex-valued exponent breaks down. This breakdown, we show, can be interpreted in terms of formation of hybrid atom-resonator modes with radiative losses that are non-trivially related to the effective coupling between individual modes. We develop a singular function expansion approach for the description of the open quantum system dynamics in such a multimode non-perturbative regime. This modal framework generalizes the normal mode description of quantum fields in a finite volume, incorporating exact radiative losses and incident quantum noise at the delimiting surface. Our results are pertinent to recent experiments with Josephson atoms coupled to high impedance Josephson junction arrays.

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Ground state excitation of an atom strongly coupled to a free quantum field

Abstract: This paper presents a nonperturbative treatment of strong-coupling induced effects in atom-field systems which cannot be seen in traditional perturbative treatments invoking compromising assumptions such as the Born-Markov, rotating wave or Fermi

Cited by 6 publications

References 111 publications

Transmission of coherent information at the onset of interactions

Transmission of coherent information at the onset of interactions

Nonequilibrium Nonlinear Open Quantum Systems I. Functional Perturbative Analysis of a Weakly Anharmonic Oscillator

Radiative Properties of an Artificial Atom coupled to a Josephson Junction Array

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