scholarly journals Higher-order exceptional point and Landau-Zener Bloch oscillations in driven non-Hermitian photonic Lieb lattices

APL Photonics ◽  
2021 ◽  
Author(s):  
Shiqiang Xia ◽  
Carlo Danieli ◽  
Yingying Zhang ◽  
Xingdong Zhao ◽  
Hai Lu ◽  
...  
Keyword(s):  
Higher Order ◽  
Exceptional Point ◽  
Bloch Oscillations

scholarly journals Non-Abelian Bloch oscillations in higher-order topological insulators

2020 ◽  
Vol 11 (1) ◽  
Author(s):  
M. Di Liberto ◽  
N. Goldman ◽  
G. Palumbo
Keyword(s):  
Quantum Dynamics ◽  
Topological Insulators ◽  
Berry Phase ◽  
Center Of Mass ◽  
Higher Order ◽  
Topological Properties ◽  
Bloch Oscillations ◽  
Abelian Gauge ◽  
Synchronization Mechanism ◽  
Wide Range

AbstractBloch oscillations (BOs) are a fundamental phenomenon by which a wave packet undergoes a periodic motion in a lattice when subjected to a force. Observed in a wide range of synthetic systems, BOs are intrinsically related to geometric and topological properties of the underlying band structure. This has established BOs as a prominent tool for the detection of Berry-phase effects, including those described by non-Abelian gauge fields. In this work, we unveil a unique topological effect that manifests in the BOs of higher-order topological insulators through the interplay of non-Abelian Berry curvature and quantized Wilson loops. It is characterized by an oscillating Hall drift synchronized with a topologically-protected inter-band beating and a multiplied Bloch period. We elucidate that the origin of this synchronization mechanism relies on the periodic quantum dynamics of Wannier centers. Our work paves the way to the experimental detection of non-Abelian topological properties through the measurement of Berry phases and center-of-mass displacements.

scholarly journals Higher-order exceptional point in a pseudo-Hermitian cavity optomechanical system

2021 ◽  
Vol 104 (6) ◽  
Author(s):  
Wei Xiong ◽  
Zhuanxia Li ◽  
Yiling Song ◽  
Jiaojiao Chen ◽  
Guo-Qiang Zhang ◽  
...  
Keyword(s):  
Higher Order ◽  
Exceptional Point ◽  
Optomechanical System ◽  
Cavity Optomechanical System

scholarly journals Non-Abelian Bloch oscillations in higher-order topological insulators

2020 ◽  
Author(s):  
Marco Di Liberto ◽  
Nathan Goldman ◽  
Giandomenico Palumbo
Keyword(s):  
Topological Insulators ◽  
Berry Phase ◽  
Center Of Mass ◽  
Higher Order ◽  
Topological Properties ◽  
Bloch Oscillations ◽  
Lattice Systems ◽  
Abelian Gauge ◽  
Synchronization Mechanism ◽  
Wide Range

Abstract Bloch oscillations (BOs) are a fundamental phenomenon by which a wave packet undergoes a periodic motion in a lattice when subjected to an external force. Observed in a wide range of synthetic lattice systems, BOs are intrinsically related to the geometric and topological properties of the underlying band structure. This has established BOs as a prominent tool for the detection of Berry phase effects, including those described by non-Abelian gauge fields. In this work, we unveil a unique topological effect that manifests in the BOs of higher-order topological insulators through the interplay of non-Abelian Berry curvature and quantized Wilson loops. It is characterized by an oscillating Hall drift that is synchronized with a topologically-protected inter-band beating and a multiplied Bloch period. We identify the origin of this synchronization mechanism through a quantum dance of Wannier centers. Our work paves the way to the experimental detection of non-Abelian topological properties in synthetic matter through the measurement of Berry phases and center-of-mass displacements.

scholarly journals Observation of exceptional point in a PT broken non-Hermitian system simulated using a quantum circuit

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Geng-Li Zhang ◽  
Di Liu ◽  
Man-Hong Yung
Keyword(s):  
Large Scale ◽  
Quantum Circuit ◽  
Higher Order ◽  
Quantum Circuits ◽  
Exceptional Point ◽  
Large Scale Systems ◽  
Zeno Effect ◽  
Programming Framework ◽  
Circuit Structure ◽  
Quantum Programming

AbstractExceptional points (EPs), the degeneracy points of non-Hermitian systems, have recently attracted great attention because of their potential of enhancing the sensitivity of quantum sensors. Unlike the usual degeneracies in Hermitian systems, at EPs, both the eigenenergies and eigenvectors coalesce. Although EPs have been widely explored, the range of EPs studied is largely limited by the underlying systems, for instance, higher-order EPs are hard to achieve. Here we propose an extendable method to simulate non-Hermitian systems and study EPs with quantum circuits. The system is inherently parity-time (PT) broken due to the non-symmetric controlling effects of the circuit. Inspired by the quantum Zeno effect, the circuit structure guarantees the success rate of the post-selection. A sample circuit is implemented in a quantum programming framework, and the phase transition at EP is demonstrated. Considering the scalable and flexible nature of quantum circuits, our model is capable of simulating large-scale systems with higher-order EPs.

scholarly journals Generalized Bloch oscillations of ultracold lattice atoms subject to higher-order gradients

2019 ◽  
Vol 100 (5) ◽  
Author(s):  
Qian-Ru Zhu ◽  
Shou-Long Chen ◽  
Shao-Jun Li ◽  
Xue-Ting Fang ◽  
Lushuai Cao ◽  
...  
Keyword(s):  
Higher Order ◽  
Bloch Oscillations

Dual systems for all: Higher-order, role-based relational reasoning as a uniquely derived feature of human cognition

2019 ◽  
Vol 42 ◽  
Author(s):  
Daniel J. Povinelli ◽  
Gabrielle C. Glorioso ◽  
Shannon L. Kuznar ◽  
Mateja Pavlic
Keyword(s):  
Temporal Reasoning ◽  
Higher Order ◽  
Important Case ◽  
Human Cognition ◽  
Relational Reasoning ◽  
Dual Systems ◽  
First Order ◽  
Reasoning System ◽  
Role Based

Abstract Hoerl and McCormack demonstrate that although animals possess a sophisticated temporal updating system, there is no evidence that they also possess a temporal reasoning system. This important case study is directly related to the broader claim that although animals are manifestly capable of first-order (perceptually-based) relational reasoning, they lack the capacity for higher-order, role-based relational reasoning. We argue this distinction applies to all domains of cognition.

Quantitative EPMA of nitrogen : A tricky element in the electron-probe microanalyzer

1992 ◽  
Vol 50 (2) ◽  
pp. 1622-1623
Author(s):  
G.F. Bastin ◽  
H.J.M. Heijligers
Keyword(s):  
Background Subtraction ◽  
Electron Probe ◽  
Detection System ◽  
Higher Order ◽  
Light Elements ◽  
Strong Suppression ◽  
Electron Probe Microanalyzer ◽  
Quantitative Epma ◽  
Peak Count ◽  
Lead Stearate

Among the ultra-light elements B, C, N, and O nitrogen is the most difficult element to deal with in the electron probe microanalyzer. This is mainly caused by the severe absorption that N-Kα radiation suffers in carbon which is abundantly present in the detection system (lead-stearate crystal, carbonaceous counter window). As a result the peak-to-background ratios for N-Kα measured with a conventional lead-stearate crystal can attain values well below unity in many binary nitrides . An additional complication can be caused by the presence of interfering higher-order reflections from the metal partner in the nitride specimen; notorious examples are elements such as Zr and Nb. In nitrides containing these elements is is virtually impossible to carry out an accurate background subtraction which becomes increasingly important with lower and lower peak-to-background ratios. The use of a synthetic multilayer crystal such as W/Si (2d-spacing 59.8 Å) can bring significant improvements in terms of both higher peak count rates as well as a strong suppression of higher-order reflections.

Effects of Higher-Order Laue Zone reflections on structure images

1993 ◽  
Vol 51 ◽  
pp. 450-451
Author(s):  
H. S. Kim ◽  
S. S. Sheinin
Keyword(s):  
Wave Vector ◽  
Theoretical Calculations ◽  
Reciprocal Lattice ◽  
Image Plane ◽  
Bloch Wave ◽  
Dynamical Theory ◽  
Higher Order ◽  
Lattice Image ◽  
Lattice Vector ◽  
Image Position

The importance of image simulation in interpreting experimental lattice images is well established. Normally, in carrying out the required theoretical calculations, only zero order Laue zone reflections are taken into account. In this paper we assess the conditions for which this procedure is valid and indicate circumstances in which higher order Laue zone reflections may be important. Our work is based on an analysis of the requirements for obtaining structure images i.e. images directly related to the projected potential. In the considerations to follow, the Bloch wave formulation of the dynamical theory has been used.The intensity in a lattice image can be obtained from the total wave function at the image plane is given by: where ϕg(z) is the diffracted beam amplitide given by In these equations,the z direction is perpendicular to the entrance surface, g is a reciprocal lattice vector, the Cg(i) are Fourier coefficients in the expression for a Bloch wave, b(i), X(i) is the Bloch wave excitation coefficient, ϒ(i)=k(i)-K, k(i) is a Bloch wave vector, K is the electron wave vector after correction for the mean inner potential of the crystal, T(q) and D(q) are the transfer function and damping function respectively, q is a scattering vector and the summation is over i=l,N where N is the number of beams taken into account.

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