9 papers
Finite Nonsignalling Resources Suffice to Simulate Entangled Qubits
Ziao Tang, Xin Wang, Ge Bai
A longstanding question in Bell nonlocality is whether finite-alphabet nonsignalling resources can reproduce the continuum of measurement correlations of partially entangled qubits…
Classical Capacity and Entanglement Cost of the Amplitude Damping Channel
Ziao Tang, Chengkai Zhu, Ge Bai +1
Determining a noisy quantum channel's classical capacity and entanglement cost generally requires regularization over many channel uses. We remove both regularizations for every qu…
Entanglement Cost of Optimal Distributed Quantum State Purification
Jiayi Zhao, Chengkai Zhu, Xin Wang +1
We determine the preshared entanglement required for spatially separated parties, restricted to local operations and classical communication, to attain globally optimal probabilist…
Per-Matrix Optimality Is Not Enough: Three-Level Optimization for Low-Rank LLM Compression
Huicheng Zhang, Xiyao Feng, Ze-Tong Li +6
Per-matrix singular value decomposition (SVD) truncation is Eckart-Young optimal in the whitened Frobenius norm, but errors from independently compressed matrices compound through…
A Sharp Local-Question Threshold for GHZ-Equatorial Completeness in Four-Player XOR Games
Ziao Tang, Chengkai Zhu, Ge Bai +2
We determine the smallest number of active questions per player at which a four-player binary exclusive-or (XOR) game of commuting-operator value one need not admit a Greenberger--…
Logical Entangling with Phantom Codes in Hypergraph Products
Keming He, Ziao Tang, Zetong Li +2
Logical entangling gates are a major source of physical spacetime overhead in fault-tolerant quantum computation. Phantom codes reduce this cost by implementing every ordered in-bl…
Simulation of Adjoints and Petz Recovery Maps for Unknown Quantum Channels
Chengkai Zhu, Ziao Tang, Guocheng Zhen +3
Transformations of quantum channels, such as the transpose, complex conjugate, and adjoint, are fundamental to quantum information theory. Given access to an unknown channel, a cen…
Quantum tunnelling-integrated optoplasmonic nanotrap enables conductance visualisation of individual proteins
Biao-Feng Zeng, Zian Wang, Yuxin Yang +17
Biological electron transfer (ET) relies on quantum mechanical tunnelling through a dynamically folded protein. Yet, the spatiotemporal coupling between structural fluctuations and…
Synthesis of Energy-Conserving Quantum Circuits with XY interaction
Ge Bai, Iman Marvian
We study quantum circuits constructed from gates and, more generally, from the entangling gates that can be realized with the XX+YY interaction alone. Such gates pre…