Publications

Publications organized by research topic, with a chronological view.

Browse publications

Stochastic Approximation, Optimization, and Probability

Learning dynamics, constant-stepsize methods, stochastic optimization, coupling, and probabilistic foundations.

  1. Wasserstein-p Central Limit Theorem Rates: From Local Dependence to Markov Chains
    Yixuan Zhang, and Qiaomin Xie
    In ACM SIGMETRICS International Conference on Measurement and Modeling of Computer Systems 2026
    Best Student Paper
    Best Paper Award Finalist
    central limit theorem Wasserstein distance dependent data
  2. Prelimit Coupling and Steady-State Convergence of Constant-stepsize Nonsmooth Contractive Stochastic Approximation
    Yixuan Zhang, Dongyan (Lucy) Huo, Yudong Chen, and Qiaomin Xie
    Operations Research 2026
    stochastic approximation coupling steady-state convergence
  3. Bias and Extrapolation in Markovian Linear Stochastic Approximation with Constant Stepsizes
    Dongyan Huo, Yudong Chen, and Qiaomin Xie
    Mathematics of Operations Research 2026
    linear stochastic approximation Markovian data bias extrapolation
  4. A Piecewise Lyapunov Analysis of Sub-quadratic SGD: Applications to Robust and Quantile Regression
    Yixuan Zhang, Dongyan (Lucy) Huo, Yudong Chen, and Qiaomin Xie
    In ACM SIGMETRICS International Conference on Measurement and Modeling of Computer Systems 2025
    stochastic gradient descent Lyapunov analysis robust regression
  5. Two-Timescale Linear Stochastic Approximation: Constant Stepsizes Go a Long Way
    Jeongyeol Kwon, Luke Dotson, Yudong Chen, and Qiaomin Xie
    In International Conference on Artificial Intelligence and Statistics (AISTATS) 2025
    linear stochastic approximation two timescales constant stepsize
  6. Coupling-based Convergence Diagnostic and Stepsize Scheme for Stochastic Gradient Descent
    Xiang Li, and Qiaomin Xie
    In AAAI Conference on Artificial Intelligence 2025
    stochastic gradient descent coupling stepsize selection
  7. The Collusion of Memory and Nonlinearity in Stochastic Approximation With Constant Stepsize
    Dongyan (Lucy) Huo, Yixuan Zhang, Yudong Chen, and Qiaomin Xie
    In Advances in Neural Information Processing Systems (NeurIPS), Spotlight 2024
    stochastic approximation constant stepsize Markovian noise
  8. Constant Stepsize Q-learning: Distributional Convergence, Bias and Extrapolation
    Yixuan Zhang, and Qiaomin Xie
    In Reinforcement Learning Conference (RLC) 2024
    Q-learning constant stepsize distributional convergence
  9. Prelimit Coupling and Steady-State Convergence of Constant-stepsize Nonsmooth Contractive Stochastic Approximation
    Yixuan Zhang, Dongyan (Lucy) Huo, Yudong Chen, and Qiaomin Xie
    In ACM SIGMETRICS International Conference on Measurement and Modeling of Computer Systems 2024
    stochastic approximation coupling constant stepsize
  10. Stochastic Methods in Variational Inequalities: Ergodicity, Bias and Refinements
    Emmanouil-Vasileios Vlatakis-Gkaragkounis, Angeliki Giannou, Yudong Chen, and Qiaomin Xie
    In International Conference on Artificial Intelligence and Statistics (AISTATS), Oral 2024
    variational inequalities stochastic optimization ergodicity
  11. Effectiveness of Constant Stepsize in Markovian LSA and Statistical Inference
    Dongyan (Lucy) Huo, Yudong Chen, and Qiaomin Xie
    In AAAI Conference on Artificial Intelligence 2024
    linear stochastic approximation statistical inference constant stepsize
  12. Bias and Extrapolation in Markovian Linear Stochastic Approximation with Constant Stepsizes
    Dongyan (Lucy) Huo, Yudong Chen, and Qiaomin Xie
    In ACM Sigmetrics 2023
    linear stochastic approximation Markovian data constant stepsize

Reinforcement Learning and MDPs

Theory and algorithms for sequential decision-making, including average-reward, offline, stable, and risk-sensitive reinforcement learning.

  1. Optimal Regret for Policy Optimization in Average Reward MDPs Without Mixing
    William Powell, Jeongyeol Kwon, Qiaomin Xie, and Hanbaek Lyu
    In Reinforcement Learning Conference (RLC) 2026
    policy optimization average-reward MDPs regret
  2. Offline Actor-Critic for Average Reward MDPs
    William Powell, Jeongyeol Kwon, Qiaomin Xie, and Hanbaek Lyu
    In Advances in Neural Information Processing Systems (NeurIPS) 2025
    offline RL actor-critic average-reward MDPs
  3. Stable Offline Value Function Learning with Bisimulation-based Representations
    Brahma S. Pavse, Yudong Chen, Qiaomin Xie, and Josiah P. Hanna
    In International Conference on Machine Learning (ICML) 2025
    offline RL value functions representation learning
  4. Learning to Stabilize Online Reinforcement Learning in Unbounded State Spaces
    Brahma S. Pavse, Matthew Zurek, Yudong Chen, Qiaomin Xie, and Josiah P. Hanna
    In International Conference on Machine Learning (ICML) 2024
    online RL stability unbounded state spaces
  5. Sharper Model-free Reinforcement Learning for Average-reward Markov Decision Processes
    Zihan Zhang, and Qiaomin Xie
    In Conference on Learning Theory (COLT) 2023
    average-reward MDPs model-free RL sample complexity
  6. ORSuite: Benchmarking Suite for Sequential Operations Models
    Christopher Archer, Siddhartha Banerjee, Mayleen Cortez, Carrie Rucker, Sean R. Sinclair, Max Solberg, Qiaomin Xie, and Christina Lee Yu
    SIGMETRICS Performance Evaluation Review 2022
    reinforcement learning operations research benchmarking
  7. Nonasymptotic Analysis of Monte Carlo Tree Search
    Devavrat Shah, Qiaomin Xie, and Zhi Xu
    Operations Research 2022
    Monte Carlo tree search planning nonasymptotic analysis
  8. Dynamic Regret of Policy Optimization in Non-Stationary Environments
    Yingjie Fei, Zhuoran Yang, Zhaoran Wang, and Qiaomin Xie
    In Advances in Neural Information Processing Systems (NeurIPS) 2020
    policy optimization nonstationarity dynamic regret
  9. POLY-HOOT: Monte-Carlo Planning in Continuous Space MDPs with Non-Asymptotic Analysis
    Weichao Mao, Kaiqing Zhang, Qiaomin Xie, and Tamer Basar
    In Advances in Neural Information Processing Systems (NeurIPS) 2020
    Monte Carlo planning continuous spaces nonasymptotic analysis
  10. Risk-Sensitive Reinforcement Learning: Near-Optimal Risk-Sample Tradeoff in Regret
    Yingjie Fei, Zhuoran Yang, Yudong Chen, Zhaoran Wang, and Qiaomin Xie
    In Advances in Neural Information Processing Systems (NeurIPS) 2020
    risk-sensitive RL regret sample complexity
  11. Stable Reinforcement Learning with Unbounded State Space
    Devavrat Shah, Qiaomin Xie, and Zhi Xu
    In Learning for Dynamics and Control (L4DC) 2020
    stability unbounded state spaces reinforcement learning
  12. Non-asymptotic analysis of Monte Carlo tree search
    Devavrat Shah, Qiaomin Xie, and Zhi Xu
    In ACM Sigmetrics 2020
    Monte Carlo tree search planning nonasymptotic analysis
  13. Q-learning with nearest neighbors
    Devavrat Shah, and Qiaomin Xie
    In Advances in Neural Information Processing Systems (NeurIPS) 2018
    Q-learning function approximation continuous state spaces

Games and Multi-Agent Learning

Learning in Markov and mean-field games, equilibrium computation, robustness, and adversarial manipulation.

  1. Inception: Efficiently Computable Misinformation Attacks on Markov Games
    Jeremy McMahan, Young Wu, Yudong Chen, Xiaojin Zhu, and Qiaomin Xie
    In Reinforcement Learning Conference (RLC) 2024
    Markov games misinformation attacks learning security
  2. Roping in Uncertainty: Robustness and Regularization in Markov Games
    Jeremy McMahan, Giovanni Artiglio, and Qiaomin Xie
    In International Conference on Machine Learning (ICML) 2024
    Markov games robustness regularization
  3. Minimally Modifying a Markov Game to Achieve Any Nash Equilibrium and Value
    Young Wu, Jeremy McMahan, Yiding Chen, Yudong Chen, Xiaojin Zhu, and Qiaomin Xie
    In International Conference on Machine Learning (ICML) 2024
    Markov games Nash equilibrium game modification
  4. Data Poisoning to Fake a Nash Equilibrium in Markov Games
    Young Wu, Jeremy McMahan, Xiaojin Zhu, and Qiaomin Xie
    In AAAI Conference on Artificial Intelligence 2024
    Markov games data poisoning Nash equilibrium
  5. Exact Policy Recovery in Offline RL with Both Heavy-Tailed Rewards and Data Corruption
    Yiding Chen, Xuezhou Zhang, Qiaomin Xie, and Xiaojin Zhu
    In AAAI Conference on Artificial Intelligence 2024
    offline RL data corruption robust learning
  6. Optimal Attack and Defense for Reinforcement Learning
    Jeremy McMahan, Young Wu, Xiaojin Zhu, and Qiaomin Xie
    In AAAI Conference on Artificial Intelligence 2024
    reinforcement learning adversarial attacks defense
  7. Learning Zero-Sum Simultaneous-Move Markov Games Using Function Approximation and Correlated Equilibrium
    Qiaomin Xie, Yudong Chen, Zhaoran Wang, and Zhuoran Yang
    Mathematics of Operations Research 2023
    Markov games function approximation correlated equilibrium
  8. Reward Poisoning Attacks on Offline Multi-Agent Reinforcement Learning
    Young Wu, Jermey McMahan, Xiaojin Zhu, and Qiaomin Xie
    In AAAI Conference on Artificial Intelligence 2023
    multi-agent RL data poisoning offline learning
  9. Learning While Playing in Mean-Field Games: Convergence and Optimality
    Qiaomin Xie, Zhuoran Yang, Zhaoran Wang, and Andreea Minca
    In International Conference on Machine Learning (ICML) 2021
    mean-field games learning dynamics equilibrium
  10. On Reinforcement Learning for Turn-based Zero-sum Markov Games
    Devavrat Shah, Varun Somani, Qiaomin Xie, and Zhi Xu
    In Proceedings of the 2020 ACM-IMS on Foundations of Data Science Conference 2020
    Markov games zero-sum games reinforcement learning
  11. Learning zero-sum simultaneous-move Markov games using function approximation and correlated equilibrium
    Qiaomin Xie, Yudong Chen, Zhaoran Wang, and Zhuoran Yang
    In Conference on Learning Theory 2020
    Markov games function approximation correlated equilibrium

Bandits and Online Decision-Making

Pure exploration, representation learning, restless bandits, online pricing, and decision-making under nonstationarity.

  1. Lyapunov-Based Sample Complexity Analysis for Weakly-Coupled MDPs
    Tianhao Wu, Matthew Zurek, Weina Wang, and Qiaomin Xie
    In Conference on Learning Theory (COLT) 2026
    weakly-coupled MDPs restless bandits sample complexity
  2. On the Peril of (Even a Little) Nonstationarity in Satisficing Regret Minimization
    Yixuan Zhang, Ruihao Zhu, and Qiaomin Xie
    arXiv preprint arXiv:2603.18514 2026
    nonstationary bandits satisficing regret online learning
  3. Contextual Online Pricing with (Biased) Offline Data
    Yixuan Zhang, Ruihao Zhu, and Qiaomin Xie
    In Advances in Neural Information Processing Systems (NeurIPS) 2025
    online pricing offline data contextual bandits
  4. Unichain and aperiodicity are sufficient for asymptotic optimality of average-reward restless bandits
    Yige Hong, Qiaomin Xie, Yudong Chen, and Weina Wang
    Mathematics of Operations Research 2025
    restless bandits average reward asymptotic optimality
  5. Pretraining Decision Transformers with Reward Prediction for In-Context Multi-task Structured Bandit Learning
    Subhojyoti Mukherjee, Josiah P Hanna, Qiaomin Xie, and Robert Nowak
    In Reinforcement Learning Conference (RLC) 2025
    decision transformers in-context learning structured bandits
  6. Multi-task Representation Learning for Fixed Budget Pure-Exploration in Linear and Bilinear Bandits
    Subhojyoti Mukherjee, Qiaomin Xie, and Robert Nowak
    In Reinforcement Learning Conference (RLC) 2025
    pure exploration multi-task learning linear bandits
  7. SPEED: Experimental Design for Policy Evaluation in Linear Heteroscedastic Bandits
    Subhojyoti Mukherjee, Qiaomin Xie, Josiah Hanna, and Robert Nowak
    In International Conference on Artificial Intelligence and Statistics (AISTATS) 2024
    linear bandits experimental design policy evaluation
  8. Multi-task Representation Learning for Pure Exploration in Bilinear Bandits
    Subhojyoti Mukherjee, Qiaomin Xie, Josiah Hanna, and Robert Nowak
    In Advances in Neural Information Processing Systems (NeurIPS) 2023
    pure exploration representation learning bilinear bandits
  9. Restless Bandits with Average Reward: Breaking the Uniform Global Attractor Assumption
    Yige Hong, Qiaomin Xie, Yudong Chen, and Weina Wang
    In Advances in Neural Information Processing Systems (NeurIPS), Spotlight, 2023
    restless bandits average reward index policies

Stochastic Networks

Queueing systems, service systems, scheduling, load balancing, bin packing, and network resource allocation.

  1. Near-Optimal Stochastic Bin-Packing in Large Service Systems with Time-Varying Item Sizes
    Yige Hong, Qiaomin Xie, and Weina Wang
    In ACM SIGMETRICS International Conference on Measurement and Modeling of Computer Systems 2024
    bin packing service systems time-varying demand
  2. Distributed Threshold-based Offloading for Heterogeneous Mobile Edge Computing
    Xudong Qin, Qiaomin Xie, and Bin Li
    In International Conference on Distributed Computing Systems (ICDCS) 2023
    mobile edge computing offloading distributed systems
  3. RL-QN: A Reinforcement Learning Framework for Optimal Control of Queueing Systems
    Bai Liu, Qiaomin Xie, and Eytan Modiano
    ACM Transactions on Modeling and Performance Evaluation of Computing Systems 2022
    reinforcement learning queueing networks network control
  4. Zero queueing for multi-server jobs
    Weina Wang, Qiaomin Xie, and Mor Harchol-Balter
    In ACM Sigmetrics 2021
    queueing systems multi-server jobs service systems
  5. Greed works—online algorithms for unrelated machine stochastic scheduling
    Varun Gupta, Benjamin Moseley, Marc Uetz, and Qiaomin Xie
    Mathematics of operations research 2020
    online scheduling stochastic systems unrelated machines
  6. Reinforcement learning for optimal control of queueing systems
    Bai Liu, Qiaomin Xie, and Eytan Modiano
    In 2019 57th Annual Allerton Conference on Communication, Control, and Computing (Allerton) 2019
    reinforcement learning queueing systems network control
  7. Stochastic online scheduling on unrelated machines
    Varun Gupta, Benjamin Moseley, Marc Uetz, and Qiaomin Xie
    In International Conference on Integer Programming and Combinatorial Optimization 2017
    online scheduling stochastic systems unrelated machines
  8. Centralized Congestion Control and Scheduling in a Datacenter
    Devavrat Shah, and Qiaomin Xie
    arXiv preprint arXiv:1710.02548 2017
    datacenter networks congestion control scheduling
  9. Scheduling with Multi-level Data Locality: Throughput and Heavy-Traffic Optimality
    Qiaomin Xie, Ali Yekkehkhany, and Yi Lu
    In 2016 IEEE Conference on Computer Communications (INFOCOM) 2016
    scheduling data locality heavy traffic
  10. Pandas: robust locality-aware scheduling with stochastic delay optimality
    Qiaomin Xie, Mayank Pundir, Yi Lu, Cristina L Abad, and Roy H Campbell
    IEEE/ACM Transactions on Networking 2016
    scheduling data locality delay optimality
  11. Power of d Choices for Large-Scale Bin Packing: A Loss Model
    Qiaomin Xie, Xiaobo Dong, Yi Lu, and R Srikant
    In ACM Sigmetrics 2015
    bin packing large-scale systems load balancing
  12. Priority algorithm for near-data scheduling: Throughput and heavy-traffic optimality
    Qiaomin Xie, and Yi Lu
    In 2015 IEEE Conference on Computer Communications (INFOCOM) 2015
    scheduling data locality heavy traffic
  13. Degree-guided map-reduce task assignment with data locality constraint
    Qiaomin Xie, and Yi Lu
    In 2012 IEEE International Symposium on Information Theory Proceedings 2012
    task assignment data locality MapReduce
  14. Join-idle-queue: A novel load balancing algorithm for dynamically scalable web services
    Yi Lu, Qiaomin Xie, Gabriel Kliot, Alan Geller, James R Larus, and Albert Greenberg
    Performance Evaluation
    International Symposium on Computer Performance, Modeling, Measurements, and Evaluation (IFIP Performance)
    2011
    Best Paper Award
    load balancing queueing systems web services