217 citations · 1.3k across the 53 of their papers we have counts for
53 papers
Convex-Gaussianity of fermionic Gibbs states in perturbation theory
Kaifeng Bu, Yuanjie Ren
We study the structure of Gibbs states in weakly perturbed interacting fermionic systems. First, for a sparse Hamiltonian with a quadratic term and a non-quadratic…
Multivariate Decoded Quantum Interferometry for Weighted Optimization
Kaifeng Bu, Weichen Gu, Xiang Li
Decoded Quantum Interferometry (DQI) is a recently introduced quantum algorithm that reduces discrete optimization to decoding with potential advantages over the best-known polynom…
Hamiltonian Decoded Quantum Interferometry for General Pauli Hamiltonians
Kaifeng Bu, Weichen Gu, Xiang Li
In this work, we study the Hamiltonian Decoded Quantum Interferometry (HDQI) for the general Hamiltonians on an -qubit system, where the coefficients $c_i\in \m…
Quantum Higher Order Fourier Analysis and the Clifford Hierarchy
Kaifeng Bu, Weichen Gu, Arthur Jaffe
We propose a mathematical framework that we call quantum, higher-order Fourier analysis. This generalizes the classical theory of higher-order Fourier analysis, which led to many a…
Decoded Quantum Interferometry Under Noise
Kaifeng Bu, Weichen Gu, Dax Enshan Koh +1
Decoded Quantum Interferometry (DQI) is a recently proposed quantum optimization algorithm that exploits sparsity in the Fourier spectrum of objective functions, with the potential…
Graphical Calculus for Fermionic Tensors
Yuanjie Ren, Kaifeng Bu, Andreas Bauer
We introduce a graphical calculus, consisting of a set of fermionic tensors with tensor-network equations, which can be used to perform various computations in fermionic many-body…
Efficient Measurement of Bosonic Non-Gaussianity
Kaifeng Bu, Bikun Li
Non-Gaussian states are essential resources in quantum information processing. In this work, we investigate methods for quantifying bosonic non-Gaussianity in many-body systems. Bu…
Quantum locally recoverable code with intersecting recovery sets
Kaifeng Bu, Weichen Gu, Xiang Li
We introduce the concept of quantum locally recoverable codes (qLRCs) with intersecting recovery sets. We derive a singleton-like bound for these codes by leveraging the additional…
Displaced Fermionic Gaussian States and their Classical Simulation
Xingjian Lyu, Kaifeng Bu
This work explores displaced fermionic Gaussian operators with nonzero linear terms. We first demonstrate equivalence between several characterizations of displaced Gaussian states…
Fermionic Gaussian Testing and Non-Gaussian Measures via Convolution
Xingjian Lyu, Kaifeng Bu
We define fermionic convolution and demonstrate its utility in characterizing fermionic non-Gaussian components, which are essential to the computational advantage of fermionic sys…
On the Hardness of Measuring Magic
Roy J. Garcia, Gaurav Bhole, Kaifeng Bu +3
Quantum computers promise to solve computational problems significantly faster than classical computers. These 'speed-ups' are achieved by utilizing a resource known as magic. Meas…
Extremality of stabilizer states
Kaifeng Bu
We investigate the extremality of stabilizer states to reveal their exceptional role in the space of all -qubit/qudit states. We establish uncertainty principles for the charact…
Magic Class and the Convolution Group
Kaifeng Bu, Arthur Jaffe, Zixia Wei
The classification of many-body quantum states plays a fundamental role in the study of quantum phases of matter. In this work, we propose an approach to classify quantum states by…
Resource Theory of Non-Revivals with Applications to Quantum Many-Body Scars
Roy J. Garcia, Kaifeng Bu, Liyuan Chen +1
The study of state revivals has a long history in dynamical systems. We introduce a resource theory to understand the use of state revivals in quantum physics, especially in quantu…
Quantum Ruzsa Divergence to Quantify Magic
Kaifeng Bu, Weichen Gu, Arthur Jaffe
In this work, we investigate the behavior of quantum entropy under quantum convolution and its application in quantifying magic. We first establish an entropic, quantum central lim…
Magic Resource Can Enhance the Quantum Capacity of Channels
Kaifeng Bu, Arthur Jaffe
We investigate the role of magic resource in the quantum capacity of channels. We consider the quantum channel of the recently proposed discrete beam splitter with the fixed enviro…
Stabilizer Testing and Magic Entropy via Quantum Fourier Analysis
Kaifeng Bu, Weichen Gu, Arthur Jaffe
Quantum Fourier analysis is an important topic in mathematical physics. We introduce a systematic protocol for testing and measuring ``magic'' in quantum states and gates, using a…
Discrete Quantum Gaussians and Central Limit Theorem
Kaifeng Bu, Weichen Gu, Arthur Jaffe
We introduce a quantum convolution and a conceptual framework to study states in discrete-variable (DV) quantum systems. All our results suggest that stabilizer states play a role…
Quantum Entropy and Central Limit Theorem
Kaifeng Bu, Weichen Gu, Arthur Jaffe
We introduce a framework to study discrete-variable (DV) quantum systems based on qudits. It relies on notions of a mean state (MS), a minimal stabilizer-projection state (MSPS), a…
Magic of Random Matrix Product States
Liyuan Chen, Roy J. Garcia, Kaifeng Bu +1
Magic, or nonstabilizerness, characterizes how far away a state is from the stabilizer states, making it an important resource in quantum computing, under the formalism of the Gott…
Wasserstein Complexity of Quantum Circuits
Lu Li, Kaifeng Bu, Dax Enshan Koh +2
Given a unitary transformation, what is the size of the smallest quantum circuit that implements it? This quantity, known as the quantum circuit complexity, is a fundamental proper…
Resource theory of quantum scrambling
Roy J. Garcia, Kaifeng Bu, Arthur Jaffe
Quantum scrambling refers to the spread of local quantum information into the many degrees of freedom of a quantum system. In this work, we introduce a resource theory of scramblin…
Barren plateaus from learning scramblers with local cost functions
Roy J. Garcia, Chen Zhao, Kaifeng Bu +1
The existence of barren plateaus has recently revealed new training challenges in quantum machine learning (QML). Uncovering the mechanisms behind barren plateaus is essential in u…
Privacy-Utility Trade-Off
Hao Zhong, Kaifeng Bu
In this paper, we investigate the privacy-utility trade-off (PUT) problem, which considers the minimal privacy loss at a fixed expense of utility. Several different kinds of privac…