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The upgrade project of Hefei Light Source storage ring is under way. In this paper, the broadband impedances of resistive wall and coated ceramic vacuum chamber were calculated using the analytic formula, the wake fields and impedances of…

Accelerator Physics · Physics 2016-01-20 Qingkun Zhang , Lin Wang , Weimin Li , Weiwei Gao

The microbunching instability usually exists in the LINAC of a free electron laser (FEL) facility. In many cases, the longitudinal space charge (LSC) is a dominant factor that generates the instability. For the highly bright electron beams,…

Accelerator Physics · Physics 2013-10-01 Dazhang Huang , King Yuen Ng , Qiang Gu

Robust control design is mainly devoted to guarantee closed-loop stability of a model-based control law in presence of parametric and structural uncertainties. The control law is usually a complex feedback law which is derived from a…

Systems and Control · Computer Science 2011-08-12 Enrico Canuto , Wilber Acuna-Bravo , Andrés Molano-Jimenez , José Ospina , Carlos Perez-Montenegro

Coherent feedback stabilises a system towards a target state without the need of a measurement, thus avoiding the quantum backaction inherent to measurements. Here, we employ optical coherent feedback to remotely cool a nanomechanical…

Previous work has shown that Benjamin-Feir unstable traveling waves of the complex Ginzburg-Landau equation (CGLE) in two spatial dimensions cannot be stabilized using a particular time-delayed feedback control mechanism known as…

Pattern Formation and Solitons · Physics 2009-11-13 Claire M. Postlethwaite , Mary Silber

In this paper, we investigate the impact of higher-order interactions on the modulational instability (MI) of Bose-Einstein Condensates (BECs) immersed in an optical lattice potential. We derive the new variational equations for the time…

Quantum Gases · Physics 2022-09-23 S. Sabari , OT. Lekeufack , SB. Yamgoue , R. Tamilthiruvalluvar , R. Radha

We investigate the coherent population trapping resonance induced by a polychromatic optical field with an asymmetric spectrum, i.e., whose sidebands equidistant from the carrier have unequal powers. A situation is considered where a…

When a beam propagates in an accelerator, it interacts with both the external fields and the self-generated electromagnetic fields. If the latter are strong enough, the interplay between them and a perturbation in the beam distribution…

Accelerator Physics · Physics 2016-01-21 G. Rumolo

I discuss how anomalies affect classical symmetries and how, in turn, the non-trivial nature of the gauge theory vacuum makes these quantum corrections troublesome. Although no solution seems in sight for the cosmological constant problem,…

High Energy Physics - Phenomenology · Physics 2009-10-31 R. D. Peccei

As network deployments become denser, interference arises as a dominant performance degradation factor. To confront with this trend, Long Term Evolution (LTE) incorporated features aiming at enabling cooperation among different base…

Information Theory · Computer Science 2017-01-24 George C. Alexandropoulos , Paul Ferrand , Constantinos B. Papadias

We present an analytic approach to the estimation of beam asymmetry effects in CMB temperature and linear polarization anisotropy experiments. We derive via perturbative expansions simple and accurate results for the case of an elliptical…

Astrophysics · Physics 2009-11-06 P. Fosalba , O. Doré , F. R. Bouchet

Magnet stability and reproducibility have become increasingly important as greater precision and beams with smaller dimension are required for research, medical and other purpose. The observed causes of mechanical and electrical instability…

Accelerator Physics · Physics 2011-03-09 N. Marks

RBM-MPC is a computationally efficient variant of Model Predictive Control (MPC) in which the Random Batch Method (RBM) is used to speed up the finite-horizon optimal control problems at each iteration. In this paper, stability and…

Optimization and Control · Mathematics 2024-03-08 Daniël Veldman , Alexandra Borkowski , Enrique Zuazua

Time-reversal symmetry suppresses electron backscattering in a quantum-spin-Hall edge, yielding quantized conductance at zero temperature. Understanding the dominant corrections in finite-temperature experiments remains an unsettled issue.…

Mesoscale and Nanoscale Physics · Physics 2018-09-11 Jukka I. Väyrynen , Dmitry I. Pikulin , Jason Alicea

Control co-design (CCD) is a technique for improving the closed-loop performance of systems through the coordinated design of both plant parameters and an optimal control policy. While model predictive control (MPC) is an attractive control…

Systems and Control · Electrical Eng. & Systems 2023-04-18 Austin L. Nash , Herschel C. Pangborn , Neera Jain

High-brightness electron beams with low energy spread at existing and future x-ray free-electron lasers are affected by various collective beam self-interactions and microbunching instabilities. The corresponding coherent optical radiation…

Accelerator Physics · Physics 2012-06-15 Christopher Behrens , Christopher Gerth , Gero Kube , Bernhard Schmidt , Stephan Wesch , Minjie Yan

High harmonics have emerged as a powerful ultrafast probe of phonon dynamics and electron-phonon interactions in solids, with most studies focusing on odd harmonics. Here, in a pump-probe setup with variable delay, we theoretically…

Optics · Physics 2026-03-11 Jinbin Li , Ulf Saalmann , Hongchuan Du , Jan Michael Rost

We propose a scheme to generate robust stationary continuous-variable entanglement in optomechanical systems, based on geometrical nonlinearity that occurs for large mechanical displacements. Such nonlinearity is often used to correct the…

Quantum Physics · Physics 2014-09-05 Philippe Djorwé , S. G. Nana Engo , Paul Woafo

Contrary to the conventional belief, time integrated asymmetry are measurable in selected final states in the neutral $B$ system at symmetric $e^+e^-$ colliders. They occur due to the interplay of weak and strong phases of two different…

High Energy Physics - Phenomenology · Physics 2009-10-28 N. G. Deshpande , Xiao-Gang He

Noise usually has an unwelcome influence on system performance. For instance, noise inevitably affects the low-frequency mechanical freedom in optomechanical experiments. However, we investigate here the beneficial effects of thermal noise…

Quantum Physics · Physics 2018-12-26 Danying Yu , Min Xie , Yanbei Cheng , Bixuan Fan
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