Parity breaking and scaling behavior in light-matter interaction

We present a frequency-renormalized multipolaron expansion method to explore the ground state of quantum Rabi model (QRM). The main idea is to take polaron as starting point to expand the ground state of QRM. The polarons are deformed and displaced oscillator states with variationally determined frequency-renormalization and displacement parameters. This method is an extension of the previously proposed polaron concept and the coherent state expansion used in the literature, which shows high efficiency in describing the physics of the QRM. The proposed method is expected to be useful for solving other more complicated light-matter interaction models.

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“…Following the notation in Refs. [8,25,[35][36][37][38], the Hamiltonian of the QRM model reads ( = 1):…”

Section: The Qrm Modelmentioning

confidence: 99%

Frequency-renormalized multipolaron expansion for the quantum Rabi model

et al. 2017

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“…As known in Ref. [17], scaling behavior would appear at the critical point of the parity breaking. To see the scaling behavior in the QRM plus Ising model, we may diagonalize Eq.…”

Section: New Parity Symmetry and Parity Breakingmentioning

confidence: 60%

“…Compared with the relevant results in Ref. [17], the Ising coupling strength ε is involved in κ, which would definitely modify the scaling behavior. Following the steps in Ref.…”

Section: Scaling Behaviormentioning

confidence: 72%

“…For example, the parity symmetry in the QRM is broken due to the addition of this bias. [11,17] If we define a parity operator P 1 = σ x ⊗P 0 with P 0 = e iπa † a , we may find [P 1 , H B ] = 0. Although this parity breaking in the BRM can present us some interesting physics, such as observation of unique scaling behavior and further understanding of the rotating-wave approximation, [17] it is natural for us to think of the possibility of restoring the broken symmetry.…”

Section: Introductionmentioning

confidence: 99%

“…[11,17] If we define a parity operator P 1 = σ x ⊗P 0 with P 0 = e iπa † a , we may find [P 1 , H B ] = 0. Although this parity breaking in the BRM can present us some interesting physics, such as observation of unique scaling behavior and further understanding of the rotating-wave approximation, [17] it is natural for us to think of the possibility of restoring the broken symmetry. We have noticed a very recent proposal [18] for a new nonlocal symmetry in the BRM, implying a generalized parity.…”

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Parity Symmetry and Parity Breaking in the Quantum Rabi Model with Addition of Ising Interaction*

Wang

Yao

2015

Commun. Theor. Phys.

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We explore the possibility to generate new parity symmetry in the quantum Rabi model after a bias is introduced. In contrast to a mathematical treatment in a previous publication [J. Phys. A 46, 265302 (2013)], we consider a physically realistic method by involving an additional spin into the quantum Rabi model to couple with the original spin by an Ising interaction. The rule can be found that the parity symmetry is broken by introducing a bias and then restored by adding new degrees of freedom. Experimental feasibility of realizing the models under discussion is investigated.

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From Quantum Rabi Model To Jaynes–Cummings Model: Symmetry‐Breaking Quantum Phase Transitions, Symmetry‐Protected Topological Transitions and Multicriticality

Ying

2021

Adv Quantum Tech

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The ground state and excitation gap are studied for the anisotropic quantum Rabi model (QRM) which connects the fundamental QRM and the Jaynes-Cummings model (JCM). While conventionally the ground state has a second-order quantum phase transition in the low frequency limit, turning on finite frequencies sheds a novel light on the phase diagram to illuminate a fine structure of first-order transition series. It is found that the conventional quantum phase transition is accompanied with a hidden symmetry breaking, whereas the emerging series transitions are topological transitions without symmetry breaking. The topological structure of the wave function provides a novel universality classification in bridging the QRM and the JCM among the diversity that arises from finite frequencies. The aspect of topological transitions provides a renewed insight for the role of the counter-rotating interaction. Moreover, it is shown that the conventionally established tricritical point is actually a pentacritical or hexacritical point and following this multicritical point emerges a series of quadruple points. Besides the emerging multicriticality and reformed universality, the result demonstrates that a single-qubit system can even exhibit analogs of topological phase transitions which traditionally occur in condensed matter.

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Parity breaking and scaling behavior in light-matter interaction

Cited by 15 publications

References 35 publications

Frequency-renormalized multipolaron expansion for the quantum Rabi model

Frequency-renormalized multipolaron expansion for the quantum Rabi model

Parity Symmetry and Parity Breaking in the Quantum Rabi Model with Addition of Ising Interaction*

From Quantum Rabi Model To Jaynes–Cummings Model: Symmetry‐Breaking Quantum Phase Transitions, Symmetry‐Protected Topological Transitions and Multicriticality

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