Entanglement resonance in the asymmetric quantum Rabi model

Shi, Yuqing; Cong, Lei; Eckle, Hans-Peter

doi:10.1103/physreva.105.062450

Cited by 13 publications

(6 citation statements)

References 70 publications

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“…In Figure 2d,f, the dotted lines are plotted by the analytic expressions for the gapped reversal transition in (57), which reproduces the boundary manifested by 𝜃 t and n zx w . Correspondingly in Figure 2e, there is no gap closing, in contrast to the gap closing in the blue belt around g R .…”

Section: Reversal Transition Of Spin Winding Without Gap Closingmentioning

confidence: 81%

Robust Topological Feature against Non‐Hermiticity in Jaynes–Cummings Model

Ying

2024

Adv Quantum Tech

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The Jaynes–Cummings Model (JCM) is a fundamental model and building block for light‐matter interactions, quantum information and quantum computation. The present work analytically analyzes the topological feature manifested by the JCM in the presence of non‐Hermiticity which may arise from dissipation and decay rates. Indeed, the eigenstates of the JCM are topologically characterized by spin windings in 2D plane. The non‐Hermiticity tilts the spin‐winding plane and induces an out‐of‐plane component, while the topological feature is maintained. In particular, besides the invariant spin texture nodes, the study reveals a non‐Hermiticity‐induced reversal transition of the tilting angle and spin winding direction with a fractional phase gain at gap closing, a partially level‐independent reversal transition without gap closing, and a completely level‐independent super‐invariant point with untilted angle and also without gap closing. The result demonstrates that the topological feature is robust against non‐Hermiticity, which may be favorable in practical applications. On the other hand, one may conversely make use of the disadvantageous dissipation and decay rates to reverse the spin winding direction, which may add a controlled way for topological manipulation of quantum systems in light‐matter interactions.

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Section: Reversal Transition Of Spin Winding Without Gap Closingmentioning

confidence: 81%

Robust Topological Feature against Non‐Hermiticity in Jaynes–Cummings Model

Ying

2024

Adv Quantum Tech

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“…Indeed, although the QRM has been proposed for more than 80 years, [ 24,63 ] studies on the QRM and its extensions are still continuing. [ 1–62 ] In the following we will provide some novel insights for the level crossings and anticrossings from topological point of view.…”

Section: Level Anti‐crossings In Energy Spectrummentioning

confidence: 99%

“…Among the intensive dialogue between mathematics and physics [ 1–62 ] triggered by the milestone work of D. Braak [ 1 ] who revealed the integrability of the quantum Rabi model (QRM), [ 24,63,64 ] few‐body quantum phase transitions (QPTs) [ 4,13–23 ] have recently attracted a special attention in the context of light–matter interactions. [ 3,4,60,65 ] In reality, the continuing experimental enhancements of couplings have brought the era of ultra‐strong [ 5,6,66–77 ] and even deep‐strong couplings, [ 77,78 ] which makes few‐body QPTs practically relevant.…”

Section: Introductionmentioning

confidence: 99%

Nodes and Spin Windings for Topological Transitions in Light–Matter Interactions

Ying

2023

Adv Quantum Tech

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The anisotropic quantum Rabi model (QRM) is the fundamental model of light–matter interactions with indispensable counter‐rotating terms in ultra‐strong couplings. By extracting different levels of topological information a new light is shed on the energy spectrum of the anisotropic QRM. Besides conventional topological transitions (TTs) at gap closing, abundant unconventional TTs are unveiled underlying level anticrossings without gap closing by tracking the wave‐function nodes, including a particular unconventional TT which turns out to be universal for different energy levels. On the other hand, it is found that the nodes have a correspondence to spin windings, which not only endows the nodes a more explicit topological character in supporting single‐qubit TTs but also turns the topological information physically detectable. Furthermore, hidden small‐spin‐knot transitions are exposed for the ground state, while more kinds of spin‐knot transitions emerge in excited states including unmatched node numbers and spin winding numbers. Based on node sorting, algebraic formulation is established to decode the topological information encoded geometrically in the wave functions and spin windings.

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“…The term ϵσ x in the Hamiltonian H ϵ appears naturally in implementations with flux qubits [15] (see [6,7] for a recent important experiment using this implementation to reach the deep strong coupling regime of the QRM and AQRM). The AQRM has been studied from the viewpoint of topology in [16] and with respect to entanglement in [17].…”

Section: Introductionmentioning

confidence: 99%

Spacing distribution for quantum Rabi models ^*

Thi Hoai Nguyen,

Reyes-Bustos,

Braak

et al. 2024

J. Phys. A: Math. Theor.

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The asymmetric quantum Rabi model (AQRM) is a fundamental model in quantum optics describing the interaction of light and matter. Besides its immediate physical interest, the AQRM possesses an intriguing mathematical structure which is far from being completely understood. In this paper, we focus on the distribution of the level spacing, the difference between consecutive eigenvalues of the AQRM in the limit of high energies, i.e. large quantum numbers. In the symmetric case, that is the quantum Rabi model (QRM), the spacing distribution for each parity (given by the Z 2 -symmetry) is fully clarified by an asymptotic expression derived by de Monvel and Zielinski, though some questions remain for the full spectrum spacing. However, in the general AQRM case, there is no parity decomposition for the eigenvalues. In connection with numerically exact studies and recent theoretical results, we describe the spacing distribution for the AQRM which is characterized by a new type of periodicity and symmetric behavior of the distribution with respect to the bias parameter, reflecting the hidden symmetry of the AQRM. In addition, we observe in the AQRM the excited state quantum phase transition for large values of the bias parameter, analogous to the QRM with large qubit energy, and an internal symmetry of the level spacing distribution for fixed bias. This novel symmetry is independent from the symmetry for half-integer bias and not explained by current theoretical knowledge.

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Entanglement resonance in the asymmetric quantum Rabi model

Cited by 13 publications

References 70 publications

Robust Topological Feature against Non‐Hermiticity in Jaynes–Cummings Model

Robust Topological Feature against Non‐Hermiticity in Jaynes–Cummings Model

Nodes and Spin Windings for Topological Transitions in Light–Matter Interactions

Spacing distribution for quantum Rabi models ^*

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Entanglement resonance in the asymmetric quantum Rabi model

Cited by 13 publications

References 70 publications

Robust Topological Feature against Non‐Hermiticity in Jaynes–Cummings Model

Robust Topological Feature against Non‐Hermiticity in Jaynes–Cummings Model

Nodes and Spin Windings for Topological Transitions in Light–Matter Interactions

Spacing distribution for quantum Rabi models *

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Product

Resources

About

Spacing distribution for quantum Rabi models ^*