Exponential time-scaling of estimation precision by reaching a quantum critical point

Garbe, Louis; Abah, Obinna; Felicetti, Simone; Puebla, Ricardo

doi:10.1103/physrevresearch.4.043061

Cited by 17 publications

(14 citation statements)

References 80 publications

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“…Such a physical decoding not only turns the topological information to be detectable, but also might provide possibility for designing topological quantum devices or sensors. In such a perspective, both the conventional TTs and unconventional ones addressed in the present work might have some potential applications as both gap‐closing [ 35 ] and gapped [ 37 ] situations are applicable, while the unconventional TTs might have some more advantage in avoiding the detrimental slowing‐down effect in preparation of probe states close to transitions. [ 37 ]…”

Section: Conclusion and Discussionmentioning

confidence: 99%

“…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%

“…[ 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. Along with the applications of few‐body QPTs, for example, in critical quantum metrology, [ 34–37 ] single‐qubit topological phase transitions have also added an interesting topic in the mathematics–physics dialogue with a renewed insight for the transitions in light–matter interactions. [ 20–22 ]…”

Section: Introductionmentioning

confidence: 99%

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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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Section: Conclusion and Discussionmentioning

confidence: 99%

Section: Level Anti‐crossings In Energy Spectrummentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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

Ying

2023

Adv Quantum Tech

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“…Introduction.-With the experimental advances into the era of ultra-strong coupling in light-matter interactions [1,2] and the theoretical efforts on the fundamental Quantum Rabi model (QRM) , finite-component quantum phase transitions (QPTs) have recently received an increasing attention [5][6][7][8][9][10][11][12][13][14][15][16][17][18]. Practical applications of the finite-component QPTs have been exploited in critical quantum metrology and quantum information science [39][40][41][42][43][44][45].…”

mentioning

confidence: 99%

Switchable Superradiant Phase Transition with Kerr Magnons

Liu¹,

Xiong²,

Ying³

2023

Preprint

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The superradiant phase transition (SPT) has been widely studied in cavity quantum electrodynamics (CQED). However, this SPT is still subject of ongoing debates due to the no-go theorem induced by the so-called A 2 term (AT). We propose a hybrid quantum system, consisting of a singlemode cavity simultaneously coupled to both a two-level system and yttrium-iron-garnet sphere supporting magnons with Kerr nonlinearity, to restore the SPT against the AT. The Kerr magnons here can effectively introduce an additional strong and tunable AT to counteract the intrinsic AT, via adiabatically eliminating the degrees of freedom of the magnons. We show that the Kerr magnons induced SPT can exist in both cases of ignoring and including the intrinsic AT. Without the intrinsic AT, the critical coupling strength can be dramatically reduced by introducing the Kerr magnons, which greatly relaxes the experimental conditions for observing the SPT. With the intrinsic AT, the forbidden SPT can be recovered with the Kerr magnons in a reversed way. Our work paves a potential way to manipulate the SPT against the AT in hybrid systems combining CQED and nonlinear magnonics.

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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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Exponential time-scaling of estimation precision by reaching a quantum critical point

Cited by 17 publications

References 80 publications

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

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

Switchable Superradiant Phase Transition with Kerr Magnons

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

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