Search Results for author: Tongyang Li

Found 17 papers, 3 papers with code

Quantum Langevin Dynamics for Optimization

no code implementations27 Nov 2023 Zherui Chen, Yuchen Lu, Hao Wang, Yizhou Liu, Tongyang Li

Finally, based on the observations when comparing QLD with classical Fokker-Plank-Smoluchowski equation, we propose a time-dependent QLD by making temperature and $\hbar$ time-dependent parameters, which can be theoretically proven to converge better than the time-independent case and also outperforms a series of state-of-the-art quantum and classical optimization algorithms in many non-convex landscapes.

Near-Optimal Quantum Coreset Construction Algorithms for Clustering

no code implementations5 Jun 2023 Yecheng Xue, Xiaoyu Chen, Tongyang Li, Shaofeng H. -C. Jiang

$k$-Clustering in $\mathbb{R}^d$ (e. g., $k$-median and $k$-means) is a fundamental machine learning problem.

Clustering

Quantum Algorithms for Sampling Log-Concave Distributions and Estimating Normalizing Constants

no code implementations12 Oct 2022 Andrew M. Childs, Tongyang Li, Jin-Peng Liu, Chunhao Wang, Ruizhe Zhang

We also prove a $1/\epsilon^{1-o(1)}$ quantum lower bound for estimating normalizing constants, implying near-optimality of our quantum algorithms in $\epsilon$.

On Quantum Speedups for Nonconvex Optimization via Quantum Tunneling Walks

1 code implementation29 Sep 2022 Yizhou Liu, Weijie J. Su, Tongyang Li

Classical algorithms are often not effective for solving nonconvex optimization problems where local minima are separated by high barriers.

Quantum Speedups of Optimizing Approximately Convex Functions with Applications to Logarithmic Regret Stochastic Convex Bandits

no code implementations26 Sep 2022 Tongyang Li, Ruizhe Zhang

As an application, we give a quantum algorithm for zeroth-order stochastic convex bandits with $\tilde{O}(n^{5}\log^{2} T)$ regret, an exponential speedup in $T$ compared to the classical $\Omega(\sqrt{T})$ lower bound.

Adaptive Online Learning of Quantum States

no code implementations1 Jun 2022 Xinyi Chen, Elad Hazan, Tongyang Li, Zhou Lu, Xinzhao Wang, Rui Yang

In the fundamental problem of shadow tomography, the goal is to efficiently learn an unknown $d$-dimensional quantum state using projective measurements.

Quantum Multi-Armed Bandits and Stochastic Linear Bandits Enjoy Logarithmic Regrets

no code implementations30 May 2022 Zongqi Wan, Zhijie Zhang, Tongyang Li, Jialin Zhang, Xiaoming Sun

In this paper, we study MAB and SLB with quantum reward oracles and propose quantum algorithms for both models with $O(\mbox{poly}(\log T))$ regrets, exponentially improving the dependence in terms of $T$.

Multi-Armed Bandits reinforcement-learning +1

Escape saddle points by a simple gradient-descent based algorithm

no code implementations NeurIPS 2021 Chenyi Zhang, Tongyang Li

Compared to the previous state-of-the-art algorithms by Jin et al. with $\tilde{O}((\log n)^{4}/\epsilon^{2})$ or $\tilde{O}((\log n)^{6}/\epsilon^{1. 75})$ iterations, our algorithm is polynomially better in terms of $\log n$ and matches their complexities in terms of $1/\epsilon$.

Sublinear classical and quantum algorithms for general matrix games

no code implementations11 Dec 2020 Tongyang Li, Chunhao Wang, Shouvanik Chakrabarti, Xiaodi Wu

We give a sublinear classical algorithm that can interpolate smoothly between these two cases: for any fixed $q\in (1, 2]$, we solve the matrix game where $\mathcal{X}$ is a $\ell_{q}$-norm unit ball within additive error $\epsilon$ in time $\tilde{O}((n+d)/{\epsilon^{2}})$.

Quantum algorithms for escaping from saddle points

no code implementations20 Jul 2020 Chenyi Zhang, Jiaqi Leng, Tongyang Li

Compared to the classical state-of-the-art algorithm by Jin et al. with $\tilde{O}(\log^{6} (n)/\epsilon^{1. 75})$ queries to the gradient oracle (i. e., the first-order oracle), our quantum algorithm is polynomially better in terms of $\log n$ and matches its complexity in terms of $1/\epsilon$.

Quantum exploration algorithms for multi-armed bandits

1 code implementation14 Jul 2020 Daochen Wang, Xuchen You, Tongyang Li, Andrew M. Childs

Identifying the best arm of a multi-armed bandit is a central problem in bandit optimization.

Multi-Armed Bandits

Quantum Wasserstein Generative Adversarial Networks

1 code implementation NeurIPS 2019 Shouvanik Chakrabarti, Yiming Huang, Tongyang Li, Soheil Feizi, Xiaodi Wu

The study of quantum generative models is well-motivated, not only because of its importance in quantum machine learning and quantum chemistry but also because of the perspective of its implementation on near-term quantum machines.

Quantum Machine Learning

Sampling-based sublinear low-rank matrix arithmetic framework for dequantizing quantum machine learning

no code implementations14 Oct 2019 Nai-Hui Chia, András Gilyén, Tongyang Li, Han-Hsuan Lin, Ewin Tang, Chunhao Wang

Motivated by quantum linear algebra algorithms and the quantum singular value transformation (SVT) framework of Gily\'en, Su, Low, and Wiebe [STOC'19], we develop classical algorithms for SVT that run in time independent of input dimension, under suitable quantum-inspired sampling assumptions.

BIG-bench Machine Learning Clustering +2

Sublinear quantum algorithms for training linear and kernel-based classifiers

no code implementations4 Apr 2019 Tongyang Li, Shouvanik Chakrabarti, Xiaodi Wu

We design sublinear quantum algorithms for the same task running in $\tilde{O}(\sqrt{n} +\sqrt{d})$ time, a quadratic improvement in both $n$ and $d$.

Quantization

Distributional property testing in a quantum world

no code implementations2 Feb 2019 András Gilyén, Tongyang Li

The presented approach is a natural fit for distributional property testing both in the classical and the quantum case, demonstrating the first speed-ups for testing properties of density operators that can be accessed coherently rather than only via sampling; for classical distributions our algorithms significantly improve the precision dependence of some earlier results.

Learning Theory

Quantum-inspired sublinear algorithm for solving low-rank semidefinite programming

no code implementations10 Jan 2019 Nai-Hui Chia, Tongyang Li, Han-Hsuan Lin, Chunhao Wang

In this paper, we present a proof-of-principle sublinear-time algorithm for solving SDPs with low-rank constraints; specifically, given an SDP with $m$ constraint matrices, each of dimension $n$ and rank $r$, our algorithm can compute any entry and efficient descriptions of the spectral decomposition of the solution matrix.

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