43 citations · 66 across the 17 of their papers we have counts for
6 papers · 1 filter
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…