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Robust Quantum Control in Closed and Open Systems: Theory and Practice

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arXiv 2023年

作者： Weidner, C.A. Reed, E.A. Monroe, J. Sheller, B. O’Neil, S. Maas, E. Jonckheere, E.A. Langbein, F.C. Schirmer, S.G. Quantum Engineering Technology Laboratories H. H. Wills Physics Laboratory Department of Electrical and Electronic Engineering University of Bristol BristolBS8 1FD United Kingdom Department of Electrical and Computer Engineering Texas Tech University LubbockTX79409 United States Boeing Research & Technology Huntington BeachCA92647 United States Department of Computer Science Drake University 2507 University Ave Des MoinesIA50311 United States Department of Electrical and Computer Engineering University of Southern California Los AngelesCA90089 United States School of Computer Science and Informatics Cardiff University CardiffCF24 4AG United Kingdom Swansea University SwanseaSA2 8PP United Kingdom

Robust control of quantum systems is an increasingly relevant field of study amidst the second quantum revolution, but there remains a gap between taming quantum physics and robust control in its modern analytical form that culminated in fundamental performance bounds. With certain exceptions such as quantum optical systems that can be modelled as linear stochastic differential equations, quantum systems are not amenable to linear, time-invariant, measurement-based robust control techniques, and thus novel gap-bridging techniques must be developed. This survey is written for control theorists to provide a review of the current state of quantum control and outline the challenges faced in trying to apply modern robust control to quantum systems. We present issues that arise when applying classical robust control theory to quantum systems, typical methods used by quantum physicists to explore such systems and their robustness, as well as a discussion of open problems to be addressed in the field. We focus on general, practical applications and recent work to enable control researchers to contribute to advancing this burgeoning field. Copyright © 2023, The Authors. All rights reserved.

关键词： Stochastic systems

Data-Induced Intelligent Kalman Filtering for Beam Prediction and Tracking of Millimeter Wave Communications

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Data-Induced Intelligent Kalman Filtering for Beam Predictio...

IEEE Conference on Global Communications (GLOBECOM)

作者： Jianjun Zhang Yongming Huang Christos Masouros Xiaohu You College of Computer Science and Technology Nanjing University of Aeronautics and Astronautics Nanjing China The Purple Mountain Laboratories Nanjing China National Mobile Communications Research Laboratory Southeast University Nanjing China Department of Electronic & Electrical Engineering University College London London U.K.

Beam prediction and tracking (BPT) are key technology for millimeter wave communications. Typical techniques include Kalman filtering (KF) and Gaussian process (GP) regression. However, KF requires explicit system dynamics, which is difficult to obtain for complicated scenarios. In contrast, thanks to the data-driven manner, GP regression circumvents this challenging, which, however, suffers from prohibitive computational complexity. To tackle this issue, we propose a novel hybrid model and data driven approach, referred to as data-induced intelligent Kalman filtering (DIIKF). DIIKF learns the system dynamics via the data-driven manner, which can enjoy the advantages of both KF and GP while overcoming their drawbacks. In view that the system dynamics is available, we further propose long-term prediction and design an efficient algorithm. Simulation results show that our method approaches the optimal oracle solution (in terms of effective achievable rate), with the linear complexity order.

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Physics-informed Inverse Design of Multi-bit Programmable Metasurfaces

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arXiv 2024年

作者： Xu, Yucheng Yang, Jia-Qi Fan, Kebin Wang, Sheng Wu, Jingbo Zhang, Caihong Zhan, De-Chuan Padilla, Willie J. Jin, Biaobing Chen, Jian Wu, Peiheng Key Laboratory of Optoelectronic Devices and Systems with Extreme Performances of MOE School of Electronic Science and Engineering Nanjing University Nanjing210023 China Purple Mountain Laboratories Nanjing211111 China State Key Laboratory for Novel Software Technology Nanjing University Nanjing210023 China Department of Electrical and Computer Engineering Duke University Box 90291 DurhamNC27708 United States

Emerging reconfigurable metasurfaces offer various possibilities in programmatically manipulating electromagnetic waves across spatial, spectral, and temporal domains, showcasing great potential for enhancing terahertz applications. However, they are hindered by limited tunability, particularly evident in relatively small phase tuning over 270o, due to the design constraints with time-intensive forward design methodologies. Here, we demonstrate a multi-bit programmable metasurface capable of terahertz beam steering, facilitated by a developed physics-informed inverse design (PIID) approach. Through integrating a modified coupled mode theory (MCMT) into residual neural networks, our PIID algorithm not only significantly increases the design accuracy compared to conventional neural networks but also elucidates the intricate physical relations between the geometry and the modes. Without decreasing the reflection intensity, our method achieves the enhanced phase tuning as large as 300o. Additionally, we experimentally validate the inverse designed programmable beam steering metasurface, which is adaptable across 1-bit, 2-bit, and tri-state coding schemes, yielding a deflection angle up to 68o and broadened steering coverage. Our demonstration provides a promising pathway for rapidly exploring advanced metasurface devices, with potentially great impact on communication and imaging technologies. © 2024, CC0.

关键词： Tuning

A Tutorial on Movable Antennas for Wireless Networks

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IEEE Communications Surveys and Tutorials 2025年

作者： Zhu, Lipeng Ma, Wenyan Mei, Weidong Zeng, Yong Wu, Qingqing Ning, Boyu Xiao, Zhenyu Shao, Xiaodan Zhang, Jun Zhang, Rui National University of Singapore Department of Electrical and Computer Engineering 117583 Singapore National Key Laboratory of Wireless Communications Chengdu611731 China Southeast University National Mobile Communications Research Laboratory Frontiers Science Center for Mobile Information Communication and Security Nanjing210096 China Purple Mountain Laboratories Nanjing211111 China Shanghai Jiao Tong University Department of Electronic Engineering Shanghai200240 China Beihang University School of Electronic and Information Engineering Beijing100191 China University of Waterloo Department of Electrical and Computer Engineering WaterlooONN2L 3G1 Canada Beijing Institute of Technology State Key Laboratory of CNS/ATM Miit Key Laboratory of Complex-field Intelligent Sensing Beijing100081 China The Chinese University of HongKong School of Science and Engineering Shenzhen Research Institute of Big Data Guangdong Shenzhen518172 China

Movable antenna (MA) has been recognized as a promising technology to enhance the performance of wireless communication and sensing by enabling antenna movement. Such a significant paradigm shift from conventional fixed antennas (FAs) to MAs offers tremendous new opportunities towards realizing more versatile, adaptive and efficient next-generation wireless networks such as 6G. In this paper, we provide a comprehensive tutorial on the fundamentals and advancements in the area of MA-empowered wireless networks. First, we overview the historical development and contemporary applications of MA technologies. Next, to characterize the continuous variation in wireless channels with respect to antenna position and/or orientation, we present new field-response channel models tailored for MAs, which are applicable to narrowband and wideband systems as well as far-field and near-field propagation conditions. Subsequently, we review the state-of-the-art architectures for implementing MAs and discuss their practical constraints. A general optimization framework is then formulated to fully exploit the spatial degrees of freedom (DoFs) in antenna movement for performance enhancement in wireless systems. In particular, we delve into two major design issues for MA systems. First, we address the intricate antenna movement optimization problem for various communication and/or sensing systems to maximize the performance gains achievable by MAs. Second, we deal with the challenging channel acquisition issue in MA systems for reconstructing the channel mapping between arbitrary antenna positions inside the transmitter and receiver regions. Moreover, we show existing prototypes developed for MA-aided communication/sensing and the experimental results based on them. Finally, the extension of MA design to other wireless systems and its synergy with other emerging wireless technologies are discussed. We also highlight promising research directions in this area to inspire future investigatio

关键词： Antenna arrays

Unlocking High Performance, Ultra-Low Power Van der Waals Transistors: Towards Back-End-of-Line In-Sensor Machine Vision Applications

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arXiv 2023年

作者： Alolaiyan, Olaiyan Albwardi, Shahad Alsaggaf, Sarah Tabbakh, Thamer DelRio, Frank W. Amer, Moh R. Center of Excellence for Green Nanotechnologies Microelectronics and Semiconductor Institute King Abdulaziz City for Science and Technology Riyadh11442 Saudi Arabia Sandia National Laboratories Material Physical and Chemical Sciences Center AlbuquerqueNM87123 United States Department of Electrical and Computer Engineering University of Southern California Los AngelesCA90089 United States Department of Electrical and Computer Engineering University of California Los Angeles Los AngelesCA90095 United States

Recent reports on machine learning (ML) and machine vision (MV) devices have demonstrated the potentials of 2D materials and devices. Yet, scalable 2D devices are being challenged by contact resistance and Fermi Level Pinning (FLP), power consumption, and low-cost CMOS compatible lithography processes. To enable CMOS+2D, it is essential to find a proper lithography strategy that can fulfill these requirements. Here, we explore modified van der Waals (vdW) deposition lithography and demonstrate a relatively new class of van-der-WaalsField-Effect-Transistors (vdW-FETs) based on 2D materials. This lithography strategy enables us to unlock high performance devices evident by high current on-off ratio (Ion/Ioff), high turn-on current density (Ion), and weak Fermi Level Pinning (FLP). We utilize this approach to demonstrate a gate-tunable near-ideal diode using MoS2/WSe2 heterojunction with an ideality factor of ~1.65 and current rectification of 102. We finally demonstrate a highly sensitive, scalable, and ultra-low power phototransistor using MoS2/WSe2 vdW-FET for Back-End-of-Line (BEOL) integration. Our phototransistor exhibits the highest gate-tunable photoresponsivity achieved to date for white light detection with ultra-low power dissipation, enabling ultra-sensitive, ultra-fast, and efficient optoelectronic applications such as in-sensor neuromorphic machine vision. Our approach shows the great potential of modified vdW deposition lithography for back-end-of-line CMOS+2D applications. © 2023, CC BY.

关键词： Van der Waals forces

Exploring Layer Thinning of Exfoliated β-Tellurene and Room Temperature Photoluminescence with Large Exciton Binding Energy Revealed in β-TeO2

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arXiv 2023年

作者： Aljalham, Ghadeer Alsaggaf, Sarah Albawardi, Shahad Tabbakh, Thamer DelRio, Frank W. Amer, Moh R. Center of Excellence for Green Nanotechnologies Microelectronics and Semiconductor Institute King Abdulaziz City for Science and Technology Riyadh11442 Saudi Arabia Sandia National Laboratories Material Physical and Chemical Sciences Center AlbuquerqueNM87123 United States Department of Electrical and Computer Engineering University of California Los Angeles Los AngelesCA90095 United States Department of Electrical and Computer Engineering University of Southern California Los AngelesCA90089 United States

Due to its tunable band gap, anisotropic behavior, and superior thermoelectric properties, device applications using layered tellurene (Te) are becoming attractive. Here, we report a thinning technique for exfoliated tellurene nanosheets using thermal annealing in an oxygen environment. We characterize different thinning parameters including temperature and annealing time. Based on our measurements, we show that controlled layer thinning occurs in the narrow temperature range of 325 oC to 350 oC. We also show a reliable method to form β-tellurene oxide (β- TeO2), which is an emerging wide band gap semiconductor with promising electronic and optoelectronic properties. This wide band gap semiconductor exhibits a broad photoluminescence (PL) spectrum with multiple peaks covering the range 1.76 eV to 2.08 eV. This PL emission coupled with Raman spectra are strong evidence of the formation of 2D βTeO2. We discuss the results obtained and the mechanisms of Te thinning and β-TeO2 formation at different temperature regimes. We also discuss the optical band gap of β-TeO2 and show the existence of pronounced excitonic effects evident by the large exciton binding energy in this 2D β-TeO2 system that reach 1.54 eV to 1.62 eV for bulk to monolayer, respectively. Our work can be utilized to have better control over Te nanosheet thickness. It also sheds light on the formation of well-controlled β-TeO2 layered semiconductor for electronic and optoelectronic applications. © 2023, CC BY.

关键词： Photoluminescence

Sample-efficient Model-based Reinforcement Learning for Quantum Control

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arXiv 2023年

作者： Khalid, Irtaza Weidner, Carrie A. Jonckheere, Edmond A. Schirmer, Sophie G. Langbein, Frank C. School of Computer Science and Informatics Cardiff University CardiffCF24 4AG United Kingdom Quantum Engineering Technology Laboratories H. H. Wills Physics Laboratory Department of Electrical and Electronic Engineering University of Bristol BristolBS8 1FD United Kingdom Department of Electrical and Computer Engineering University of Southern California Los AngelesCA90007 United States Department of Physics Swansea University SwanseaSA2 8PP United Kingdom

We propose a model-based reinforcement learning (RL) approach for noisy time-dependent gate optimization with reduced sample complexity over model-free RL. Sample complexity is defined as the number of controller interactions with the physical system. Leveraging an inductive bias, inspired by recent advances in neural ordinary differential equations (ODEs), we use an auto-differentiable ODE, parametrized by a learnable Hamiltonian ansatz, to represent the model approximating the environment, whose time-dependent part, including the control, is fully known. Control alongside Hamiltonian learning of continuous time-independent parameters is addressed through interactions with the system. We demonstrate an order of magnitude advantage in sample complexity of our method over standard model-free RL in preparing some standard unitary gates with closed and open system dynamics, in realistic computational experiments incorporating single shot measurements, arbitrary Hilbert space truncations, and uncertainty in Hamiltonian parameters. Also, the learned Hamiltonian can be leveraged by existing control methods like GRAPE for further gradient-based optimization with the controllers found by RL as initializations. Our algorithm, which we apply to nitrogen vacancy (NV) centers and transmons, is well suited for controlling partially characterized one- and two-qubit systems. © 2023, CC BY.

关键词： Reinforcement learning

Exploring Y1 Communications and Services in O-RAN: Background, Privacy, and Security

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IEEE Open Journal of the Communications Society

IEEE Open Journal of the Communications Society 2025年 6卷 4638-4666页

作者： Sachinkumar B. Mallikarjun Mohammad Asif Habibi Mihirraj Dixit Xavier Costa-Pérez Mérouane Debbah Hans D. Schotten Department of Electrical and Computer Engineering Division of Wireless Communications and Radio Navigation University of Kaiserslautern (RPTU) Kaiserslautern Germany 6G Networks Research and Development Department NEC Laboratories Europe Heidelberg Germany Network Engineering Department Universitat Politècnica de Catalunya Barcelona Spain Department of AI Driven Systems i2CAT Research Center Barcelona Spain Department of AI Driven Systems Catalan Institution for Research and Advanced Studies (ICREA) Barcelona Spain Department of Computer and Information Engineering KU 6G Research Center Khalifa University of Science and Technology Abu Dhabi UAE CentraleSupelec University Paris-Saclay Gif-sur-Yvette France Intelligent Networking Research Group German Research Center for Artificial Intelligence (DFKI) Kaiserslautern Germany

In the latest open radio access network (O-RAN) architecture, the Y1 interface has been introduced to grant authorized parties, known as Y1 consumers, access to and utilization of Y1 data within the near-real-time RAN intelligent controller (Near-RT RIC). The primary objective of enabling communication between Y1 consumers and the Near-RT RIC is to facilitate the introduction of value-added services to O-RAN. This paper comprehensively explores Y1 communications, services, interface, data, and other essential concepts required to understand the subject matter thoroughly. We examine the security and privacy aspects of Y1 communications to ensure that all authorized parties involved in these interactions are equipped to withstand potential threats and vulnerabilities. More importantly, our research proposes a novel architectural framework for Y1 communications that integrates advanced functionalities and specifies secure communication protocols. This framework addresses the limitations of the state-of-the-art Y1 architecture by enhancing its robustness, adaptability, and efficiency. In addition, we outline the procedural flow for Y1 communications within the proposed framework, detailing the functionalities and processes it introduces. Beyond security and privacy procedures, this paper elaborates on the various phases of Y1 communications. Furthermore, a series of experiments are conducted to evaluate the effectiveness of the proposed Y1 framework. Our assessment focuses on the authentication and authorization schemes, revealing that the mutual transport layer security (mTLS) 1.3-based certificate-bound access token (CBAT) scheme demonstrated superior performance in ensuring secure and efficient communication. Additionally, the robustness of the proposed architecture is validated by evaluating its functionality in both subscription and query scenarios. Moreover, the paper discusses the proposed Y1 framework, primarily focusing on its role and functionality within the

关键词： Open RAN Security Privacy Protocols computer architecture Authentication Standards Robustness Guidelines Authorization

Disturbance-agnostic robust performance with structured uncertainties and initial state error in classical versus quantum oscillatory systems

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arXiv 2023年

作者： Jonckheere, Edmond Schirmer, Sophie G. Langbein, Frank C. Weidner, Carrie A. O'Neil, Sean The Department of Electrical and Computer Engineering University of Southern California Los AngelesCA90089 United States The Faculty of Science & Engineering Swansea University SwanseaSA2 8PP United Kingdom The School of Computer Science and Informatics Cardiff University CardiffCF24 3AA United Kingdom The Quantum Engineering Technology Laboratories University of Bristol BristolBS8 1FD United Kingdom

A method to quantify robust performance for situations where structured parameter variations and initial state errors rather than extraneous disturbances are the main performance limiting factors is presented. The approach is based on the error dynamics, the difference between nominal and perturbed dynamics, driven by either the unperturbed or perturbed state, rather than an artificially imposed disturbance. The unperturbed versus perturbed dichotomy can be interpreted as the relative error dynamics scaled by either the unperturbed or perturbed dynamics. The error dynamics driven by unperturbed state has the unique feature of decoupling the effect of physically meaningful uncertainties from an additive disturbance. The perturbed case offers the possibility to side-step Structured Singular Value (SSV) computations. Applications to a lightly damped mechanical system and a slowly dephasing quantum system demonstrate the usefulness of the concepts across a broad range of systems. Finally, a fixed-point algorithm specifically developed for quantum systems with state transitions depending in a nonlinear fashion on uncertainties is proposed as the substitute for classical SSV. Copyright © 2023, The Authors. All rights reserved.

关键词： Robust control