43 citations · 66 across the 17 of their papers we have counts for
18 papers
Near-optimal incoherent tomography of low-rank quantum channels
Kean Chen, Aadil Oufkir
We study tomography for quantum channels with input dimension , output dimension , and Kraus rank at most , to within diamond norm error , using adaptive…
Quantisation of Abstract Data Types
Mingsheng Ying, Zhicheng Zhang, Kean Chen
In this paper, we introduce a notion of abstract quantum data type within the framework of universal algebra. This notion provides an algebraic foundation for describing data abstr…
Nearly Sample-Optimal Estimators for Quantum Rényi and Tsallis Entropies
Kean Chen, Qisheng Wang
In this paper, we provide estimators for quantum Rényi and Tsallis entropies with nearly optimal sample complexity. Specifically, for order , dimension , and additive error $…
Quantum Multi-Level Estimation of Functionals of Discrete Distributions
Kean Chen, Minbo Gao, Tongyang Li +2
We propose a quantum multi-level estimation framework for a functional of a discrete distribution . We partition the values into logarith…
Strict Hierarchy for Quantum Channel Certification to Unitary
Kean Chen, Qisheng Wang, Zhicheng Zhang
We consider the problem of quantum channel certification to unitary, where one is given access to an unknown -dimensional channel , and wants to test whether $\math…
Quantum channel tomography: optimal bounds and a Heisenberg-to-classical phase transition
Kean Chen, Filippo Girardi, Aadil Oufkir +2
How many black-box queries to a quantum channel are needed to learn its full classical description? This question lies at the heart of quantum channel tomography (also known as qua…
Optimal lower bound for quantum channel tomography in away-from-boundary regime
Kean Chen, Zhicheng Zhang, Nengkun Yu
Consider quantum channels with input dimension , output dimension and Kraus rank at most . Any such channel must satisfy the constraint , and the parame…
Quantum channel tomography and estimation by local test
Kean Chen, Nengkun Yu, Zhicheng Zhang
We study the estimation of an unknown quantum channel with input dimension , output dimension and Kraus rank at most . We establish a connection between…
A List of Complexity Bounds for Property Testing by Quantum Sample-to-Query Lifting
Kean Chen, Qisheng Wang, Zhicheng Zhang
Quantum sample-to-query lifting, a relation between quantum sample complexity and quantum query complexity presented in Wang and Zhang (SIAM J. Comput. 2025), was significantly str…
Inverse-free quantum state estimation with Heisenberg scaling
Kean Chen
In this paper, we present an inverse-free pure quantum state estimation protocol that achieves Heisenberg scaling. Specifically, let be a -dimens…
Approximation does not help in quantum unitary time-reversal
Kean Chen, Nengkun Yu, Zhicheng Zhang
Access to the time-reverse of an unknown quantum unitary process is widely assumed in quantum learning, metrology, and many-body physics. The fundamental task of unita…
Simultaneous Estimation of Nonlinear Functionals of a Quantum State
Kean Chen, Qisheng Wang, Zhan Yu +1
We consider a fundamental task in quantum information theory, estimating the values of , , , for an observable and a quantum state . We…
Trace Estimation of Quantum State Powers: Sample Complexity and Computational Hardness
Kean Chen, Yupan Liu, Qisheng Wang
As often emerges in various basic quantum properties such as Rényi and Tsallis entropies, the trace of quantum state powers has attracted a lot of attention. The r…
Local Test for Unitarily Invariant Properties of Bipartite Quantum States
Kean Chen, Qisheng Wang, Zhicheng Zhang
We study the power of local test for bipartite quantum states. Our central result is that, for properties of bipartite pure states, unitary invariance on one part implies an \texti…
Unitarity estimation for quantum channels
Kean Chen, Qisheng Wang, Peixun Long +1
Estimating the unitarity of an unknown quantum channel provides information on how much it is unitary, which is a basic and important problem in quantum device certif…
VeriQBench: A Benchmark for Multiple Types of Quantum Circuits
Kean Chen, Wang Fang, Ji Guan +5
In this paper, we introduce VeriQBench -- an open source benchmark for quantum circuits. It offers high-level quantum circuit abstractions of various circuit types, including 1) co…
Automatic Test Pattern Generation for Robust Quantum Circuit Testing
Kean Chen, Mingsheng Ying
Quantum circuit testing is essential for detecting potential faults in realistic quantum devices, while the testing process itself also suffers from the inexactness and unreliabili…
Quantum Algorithm for Fidelity Estimation
Qisheng Wang, Zhicheng Zhang, Kean Chen +4
For two unknown mixed quantum states and in an -dimensional Hilbert space, computing their fidelity is a basic problem with many important applications in quant…