Reconfigurable Topological Phases in Next-Nearest-Neighbor Coupled Resonator Lattices

Leykam, Daniel; Mittal, Sunil; Hafezi, Mohammad; Chong, Yidong

doi:10.1103/physrevlett.121.023901

Cited by 109 publications

(104 citation statements)

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“…We note that the system is periodic and does not require staggering the phases of the couplings, unlike the coupled-resonator system of Refs. [5,6,22] that can be dynamically reconfigured via optical, electrical, or thermal pumping [33,34]. Reconfigurability of topological systems has been demonstrated at microwave frequencies [13], but is yet to be achieved in the optical regime.…”

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confidence: 99%

“…Our system, shown in Fig. 1(a), consists of two interposed square lattices of ring resonators, with respective sites labelled A and B [33]. These site-ring resonators are coupled to their neighbors and also next-nearest neighbors using another set of rings, the link rings.…”

mentioning

confidence: 99%

“…We showed a topological-to-trivial phase transition, induced by relatively small detunings of the ring resonance frequencies. In the future, this phase transition can be utilized for robust routing and switching of light in integrated photonic devices [33]. Specifically, the silicon photonics platform can easily include active components, such as metal heaters [35] or electro-optic modulators [38] to dynamically tuning the ring resonances.…”

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confidence: 99%

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Photonic Anomalous Quantum Hall Effect

et al. 2019

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We experimentally realize a photonic analogue of the anomalous quantum Hall insulator using a twodimensional (2D) array of coupled ring resonators. Similar to the Haldane model, our 2D array is translation invariant, has zero net gauge flux threading the lattice, and exploits next-nearest neighbor couplings to achieve a topologically non-trivial bandgap. Using direct imaging and on-chip transmission measurements, we show that the bandgap hosts topologically robust edge states. We demonstrate a topological phase transition to a conventional insulator by frequency detuning the ring resonators and thereby breaking the inversion symmetry of the lattice. Furthermore, the clockwise or the counter-clockwise circulation of photons in the ring resonators constitutes a pseudospin degree of freedom. We show that the two pseudospins acquire opposite hopping phases and their respective edge states propagate in opposite directions. These results are promising for the development of robust reconfigurable integrated nanophotonic devices for applications in classical and quantum information processing.Photonics has emerged as a versatile platform to explore model systems with nontrivial band topology, a phenomenon originally associated with condensed matter systems [1,2]. For example, photonic systems have realized analogues of the integer quantum Hall effect [3][4][5][6][7], Floquet topological insulators [8][9][10][11], quantum spin-Hall and valley-Hall phases [12][13][14][15][16], as well as topological crystalline insulators [17][18][19]. From an application perspective, the inherent robustness of the topological systems has enabled the realization of photonic devices that are protected against disorder, such as optical delay lines [6,7], lasers [20][21][22], quantum light sources [23], and quantum-optic interfaces for light-matter interactions [18]. At the same time, features unique to bosonic systems, such as the possibility of introducing gain and loss into the system [24-28], parametric driving, and squeezing of light [23,29,30], have provided an opportunity to explore topological phases that cannot be realized in fermionic systems.Despite these advances, there has not yet been a nanophotonic realization of the anomalous quantum Hall phase -a two-dimensional Chern insulator with zero net gauge flux [31,32]. This is noteworthy because the various topological phases differ significantly in the origin of non-trivial band topology, and therefore offer different forms of topological protection. For instance, topological edge states in valley-Hall and topological crystalline insulator lattices manifest on internal boundaries between "opposite" domains instead of external edges [14,17], and are protected only against certain boundary deformations (e.g., 120 • bends but not 90 • bends) [14,17]. The quantum Hall and anomalous quantum Hall phases, by contrast, are significantly more robust: topological edge states can appear along external edges, and are protected irrespective of the lattice shape. Moreover, whereas the quantum Hal...

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Photonic Anomalous Quantum Hall Effect

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“…The artificial gauge field can be accomplished, for instance, by dynamic modulation, using auxiliary cavities, or by other means, as discussed and demonstrated in several recent works [37,[51][52][53][54][55][56][57][58][59][60]. We also mention that different types of reconfigurable two-dimensional photonic lattice configurations, with controllable switching between topologically trivial and non-trivial phases, have been suggested and demonstrated in several other different photonic setups [61][62][63][64][65][66].…”

Section: Model and Decoherence Dynamicsmentioning

confidence: 88%

Topological Protection and Control of Quantum Markovianity

2020

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Under the Born-Markov approximation, a qubit system, such as a two-level atom, is known to undergo a memoryless decay of quantum coherence or excitation when weakly coupled to a featureless environment. Recently, it has been shown that unavoidable disorder in the environment is responsible for non-Markovian effects and information backflow from the environment into the system owing to Anderson localization. This turns disorder into a resource for enhancing non-Markovianity in the system-environment dynamics, which could be of relevance in cavity quantum electrodynamics. Here we consider the decoherence dynamics of a qubit weakly coupled to a two-dimensional bath with a nontrivial topological phase, such as a two-level atom embedded in a two-dimensional coupled-cavity array with a synthetic gauge field realizing a quantum-Hall bath, and show that Markovianity is protected against moderate disorder owing to the robustness of chiral edge modes in the quantum-Hall bath. Interestingly, switching off the gauge field, i.e., flipping the bath into a topological trivial phase, allows one to re-introduce non-Markovian effects. Such a result indicates that changing the topological phase of a bath by a tunable synthetic gauge field can be harnessed to control non-Markovian effects and quantum information backflow in a qubit-environment system.

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“…Non-perturbative studies of nonlinear edge states and solitons have largely focused on the dynamics along the edge and been limited to numerical simulations, due to the scarceness of exact solutions to nonlinear problems [4,[14][15][16]. A notable exception are models based on nonlinear coupling, which can be understood semi-analytically in terms of nonlinearityinduced domain walls [3,9,[17][18][19][20][21]. Although realized in electronic circuits [10,20], this class of models does not admit strictly localized nonlinear modes and is challenging to scale to optics, where local on-site Kerr nonlinearities are more feasible.…”

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Topological Edge States and Gap Solitons in the Nonlinear Dirac Model

Smirnova

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Leykam

et al. 2019

Laser & Photonics Reviews

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Topological photonics has emerged recently as a novel approach for realizing robust optical circuitry, and the study of nonlinear effects in topological photonics is expected to open the door for tunability of photonic structures with topological properties. Here, the topological edge states and topological gap solitons which reside in the same band gaps described by the nonlinear Dirac model are studied, in both one and two dimensions. Strong nonlinear interactions between these dissimilar topological modes, manifested in the efficient excitation of topological edge states by scattered traveling gap solitons are revealed. Nonlinear tunability of localized states is explicated with exact analytical solutions for the two‐component spinor wave function. Our studies are complemented by spatiotemporal numerical modeling of the nonlinear scattering in 1D and 2D photonic lattices.

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Reconfigurable Topological Phases in Next-Nearest-Neighbor Coupled Resonator Lattices

Cited by 109 publications

References 35 publications

Photonic Anomalous Quantum Hall Effect

Photonic Anomalous Quantum Hall Effect

Topological Protection and Control of Quantum Markovianity

Topological Edge States and Gap Solitons in the Nonlinear Dirac Model

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