Publications (64)
Universal eigenstate entanglement of chaotic local Hamiltonians
Yichen Huang
This arXiv repository is a bundle of two closely related papers. Abstract of the first paper: In systems governed by "chaotic" local Hamiltonians, we conjecture the universality of…
Finite-size scaling analysis of eigenstate thermalization
Yichen Huang
We study the fluctuations of eigenstate expectation values in a microcanonical ensemble. Assuming the eigenstate thermalization hypothesis, an analytical formula for the finite-siz…
Out-of-time-ordered correlators in many-body localized systems
Yichen Huang, Yong-Liang Zhang, Xie Chen
In many-body localized systems, propagation of information forms a light cone that grows logarithmically with time. However, local changes in energy or other conserved quantities t…
Is microcanonical ensemble stable?
Yichen Huang
No, in a rigorous sense specified below.
Convergence of eigenstate expectation values with system size
Yichen Huang
Understanding the asymptotic behavior of physical quantities in the thermodynamic limit is a fundamental problem in statistical mechanics. In this paper, we study how fast the eige…
Perfect score on IPhO 2025 theory by Gemini agent
Yichen Huang
The International Physics Olympiad (IPhO) is the world's most prestigious and renowned physics competition for pre-university students. IPhO problems require complex reasoning base…
Efficient Task Grouping Through Samplewise Optimisation Landscape Analysis
Anshul Thakur, Yichen Huang, Soheila Molaei +2
Shared training approaches, such as multi-task learning (MTL) and gradient-based meta-learning, are widely used in various machine learning applications, but they often suffer from…
INSET: Sentence Infilling with INter-SEntential Transformer
Yichen Huang, Yizhe Zhang, Oussama Elachqar +1
Missing sentence generation (or sentence infilling) fosters a wide range of applications in natural language generation, such as document auto-completion and meeting note expansion…
Computing local properties in the trivial phase
Yichen Huang
A translation-invariant gapped local Hamiltonian is in the trivial phase if it can be connected to a completely decoupled Hamiltonian with a smooth path of translation-invariant ga…
Extensive entropy from unitary evolution
Yichen Huang
In quantum many-body systems, a Hamiltonian is called an ``extensive entropy generator'' if starting from a random product state the entanglement entropy obeys a volume law at long…
Variance-based uncertainty relations
Yichen Huang
Uncertainty relations are fundamental in quantum mechanics. Here I propose state-independent variance-based uncertainty relations for two or more arbitrary observables in finite di…
VERSA: A Versatile Evaluation Toolkit for Speech, Audio, and Music
Jiatong Shi, Hye-jin Shim, Jinchuan Tian +14
In this work, we introduce VERSA, a unified and standardized evaluation toolkit designed for various speech, audio, and music signals. The toolkit features a Pythonic interface wit…
Quantum discord for two-qubit X states: Analytical formula with very small worst-case error
Yichen Huang
Quantum discord is a measure of quantum correlation beyond entanglement. Computing quantum discord for simple quantum states is a basic problem. An analytical formula of quantum di…
Entanglement Dynamics From Random Product States: Deviation From Maximal Entanglement
Yichen Huang
We study the entanglement dynamics of quantum many-body systems and prove the following: (I) For any geometrically local Hamiltonian on a lattice, starting from a random product st…
High-precision simulation of finite-size thermalizing systems at long times
Yichen Huang
To simulate thermalizing systems at long times, the most straightforward approach is to calculate the thermal properties at the corresponding energy. In a quantum many-body system…
Robustness Tests for Automatic Machine Translation Metrics with Adversarial Attacks
Yichen Huang, Timothy Baldwin
We investigate MT evaluation metric performance on adversarially-synthesized texts, to shed light on metric robustness. We experiment with word- and character-level attacks on thre…
Deviations from maximal entanglement for eigenstates of the Sachdev-Ye-Kitaev model
Yichen Huang, Yi Tan, Norman Y. Yao
We consider mid-spectrum eigenstates of the Sachdev-Ye-Kiteav (SYK) model. We prove that for subsystems whose size is a constant fraction of the system size, the entanglement entro…
Locally accurate matrix product approximation to thermal states
Yichen Huang
In one-dimensional quantum systems with short-range interactions, a set of leading numerical methods is based on matrix product states, whose bond dimension determines the amount o…
Scaling of quantum discord in spin models
Yichen Huang
We study the scaling of quantum discord (a measure of quantum correlation beyond entanglement) in spin models analytically and systematically. We find that at finite temperature th…
Instability of localization in translation-invariant systems
Yichen Huang, Aram W. Harrow
The phenomenon of localization is usually accompanied with the presence of quenched disorder. To what extent disorder is necessary for localization is a well-known open problem. In…
Dynamics of Renyi entanglement entropy in local quantum circuits with charge conservation
Yichen Huang
In local quantum circuits with charge conservation, we initialize the system in random product states and study the dynamics of the Renyi entanglement entropy . We rigorously…
Provably efficient neural network representation for image classification
Yichen Huang
The state-of-the-art approaches for image classification are based on neural networks. Mathematically, the task of classifying images is equivalent to finding the function that map…
The Mixed Birth-death/death-Birth Moran Process
David A. Brewster, Yichen Huang, Michael Mitzenmacher +1
We study evolutionary dynamics on graphs in which each step consists of one birth and one death, also known as the Moran processes. There are two types of individuals: residents wi…
Entanglement dynamics in critical random quantum Ising chain with perturbations
Yichen Huang
We simulate the entanglement dynamics in a critical random quantum Ising chain with generic perturbations using the time-evolving block decimation algorithm. Starting from a produc…
Deviation from maximal entanglement for mid-spectrum eigenstates of local Hamiltonians
Yichen Huang
In a spin chain governed by a local Hamiltonian, we consider a microcanonical ensemble in the middle of the energy spectrum and a contiguous subsystem whose length is a constant fr…
Approximating local properties by tensor network states with constant bond dimension
Yichen Huang
Classical simulation of quantum many-body systems is a fundamental challenge due to their exponentially large Hilbert spaces. Tensor network states are a powerful ansatz to efficie…
Finite-size scaling of out-of-time-ordered correlators at late times
Yichen Huang, Fernando G. S. L. Brandao, Yong-Liang Zhang
Chaotic dynamics in quantum many-body systems scrambles local information so that at late times it can no longer be accessed locally. This is reflected quantitatively in the out-of…
A polynomial-time algorithm for the ground state of one-dimensional gapped Hamiltonians
Yichen Huang
A (deterministic) polynomial-time algorithm is proposed for approximating the ground state of (general) one-dimensional gapped Hamiltonians. Let be the energy gap, the sy…
Utility of High-Order Scheme for Unsteady Flow Simulations: Comparison with Second-Order Tool
Peng Jiang, Yichen Huang, Yong Cao +2
The objective of this work is to investigate the utility and effectiveness of the high-order scheme for simulating unsteady turbulent flows. To achieve it, the studies were conduct…
Dynamics of Rényi entanglement entropy in diffusive qudit systems
Yichen Huang
My previous work [arXiv:1902.00977] studied the dynamics of Rényi entanglement entropy in local quantum circuits with charge conservation. Initializing the system in a rand…
Quantum entropy thermalization
Yichen Huang, Aram W. Harrow
In an isolated quantum many-body system undergoing unitary evolution, the entropy of a subsystem (smaller than half the system size) thermalizes if at long times, it is to leading…
Information scrambling in chaotic systems with dissipation
Yong-Liang Zhang, Yichen Huang, Xie Chen
Chaotic dynamics in closed local quantum systems scrambles quantum information, which is manifested quantitatively in the decay of the out-of-time-ordered correlators (OTOC) of loc…
Mixed updating in structured populations
David A. Brewster, Yichen Huang, Michael Mitzenmacher +1
Evolutionary graph theory (EGT) studies the effect of population structure on evolutionary dynamics. The vertices of the graph represent the individuals. The edges denote inter…
Area law in one dimension: Degenerate ground states and Renyi entanglement entropy
Yichen Huang
An area law is proved for the Renyi entanglement entropy of possibly degenerate ground states in one-dimensional gapped quantum systems. Suppose in a chain of spins the ground…
A simple efficient algorithm in frustration-free one-dimensional gapped systems
Yichen Huang
We propose an efficient algorithm for the ground state of frustration-free one-dimensional gapped Hamiltonians. This algorithm is much simpler than the original one by Landau et al…
Entropic uncertainty relations in multidimensional position and momentum spaces
Yichen Huang
Commutator-based entropic uncertainty relations in multidimensional position and momentum spaces are derived, twofold generalizing previous entropic uncertainty relations for one-m…
Winning Gold at IMO 2025 with a Model-Agnostic Verification-and-Refinement Pipeline
Yichen Huang, Lin F. Yang
The International Mathematical Olympiad (IMO) is widely regarded as the world championship of high-school mathematics. IMO problems are renowned for their difficulty and novelty, d…
Eigenstate entanglement in the Sachdev-Ye-Kitaev model
Yichen Huang, Yingfei Gu
We study the entanglement entropy of eigenstates (including the ground state) of the Sachdev-Ye-Kitaev model. We argue for a volume law, whose coefficient can be calculated analyti…
Neuro-Symbolic Visual Reasoning: Disentangling "Visual" from "Reasoning"
Saeed Amizadeh, Hamid Palangi, Oleksandr Polozov +2
Visual reasoning tasks such as visual question answering (VQA) require an interplay of visual perception with reasoning about the question semantics grounded in perception. However…
Adding boundary terms to Anderson localized Hamiltonians leads to unbounded growth of entanglement
Yichen Huang
It is well known that in Anderson localized systems, starting from a random product state the entanglement entropy remains bounded at all times. However, we show that adding a sing…
Computing energy density in one dimension
Yichen Huang
We study the problem of computing energy density in one-dimensional quantum systems. We show that the ground-state energy per site or per bond can be computed in time (i) independe…
The Power of Arrival Times in Random-Order Online Facility Location
Yichen Huang, Shaofeng H. -C. Jiang
We study online metric facility location with uniform opening costs in the random-order model (Meyerson FOCS'01). The best previous upper bound was a -competitive randomized alg…
Quantum Hamiltonian Complexity
Sevag Gharibian, Yichen Huang, Zeph Landau +1
Constraint satisfaction problems are a central pillar of modern computational complexity theory. This survey provides an introduction to the rapidly growing field of Quantum Hamilt…
Many-body localization with mobility edges
Yichen Huang
We construct a solvable spin chain model of many-body localization (MBL) with a tunable mobility edge. This simple model not only demonstrates analytically the existence of mobilit…
Long-time properties of generic Floquet systems are approximately periodic with the driving period
Yichen Huang
A Floquet quantum system is governed by a Hamiltonian that is periodic in time. Consider the space of piecewise time-independent Floquet systems with (geometrically) local interact…
Quantum circuit complexity of one-dimensional topological phases
Yichen Huang, Xie Chen
Topological quantum states cannot be created from product states with local quantum circuits of constant depth and are in this sense more entangled than topologically trivial state…
Thermalization without eigenstate thermalization
Aram W. Harrow, Yichen Huang
In an isolated quantum many-body system undergoing unitary evolution, we study the thermalization of a subsystem, treating the rest of the system as a bath. In this setting, the ei…
Learning Interpretable Low-dimensional Representation via Physical Symmetry
Xuanjie Liu, Daniel Chin, Yichen Huang +1
We have recently seen great progress in learning interpretable music representations, ranging from basic factors, such as pitch and timbre, to high-level concepts, such as chord an…
Entropy of small subsystems in thermalizing systems
Yichen Huang
We study the entropy of small subsystems in thermalizing quantum many-body systems governed by local Hamiltonians. Assuming the eigenstate thermalization hypothesis, we derive an a…
Online Monotone Metric Embeddings
Christian Coester, Yichen Huang
Metric embeddings into structured spaces, particularly hierarchically well-separated trees (HSTs), are a fundamental tool in the design of online algorithms. In the classical onlin…
Improved concentration of Laguerre and Jacobi ensembles
Yichen Huang, Aram W. Harrow
We consider the asymptotic limits where certain parameters in the definitions of the Laguerre and Jacobi ensembles diverge. In these limits, Dette, Imhof, and Nagel proved that up…
UNITER-Based Situated Coreference Resolution with Rich Multimodal Input
Yichen Huang, Yuchen Wang, Yik-Cheung Tam
We present our work on the multimodal coreference resolution task of the Situated and Interactive Multimodal Conversation 2.0 (SIMMC 2.0) dataset as a part of the tenth Dialog Syst…
Autonomous disproofs of the sum-product conjecture over with GPT-5.5 Pro
Yichen Huang
OpenAI's recent disproof of the ErdÅs unit distance conjecture marked a milestone for AI in mathematics. It also inspired another breakthrough: a human disproof of the ErdÅs--Sze…
Neural network representation of tensor network and chiral states
Yichen Huang, Joel E. Moore
We study the representational power of Boltzmann machines (a type of neural network) in quantum many-body systems. We prove that any (local) tensor network state has a (local) neur…
Excited-state entanglement and thermal mutual information in random spin chains
Yichen Huang, Joel E. Moore
Entanglement properties of excited eigenstates (or of thermal mixed states) are difficult to study with conventional analytical methods. We approach this problem for random spin ch…
Correlation Length versus Gap in Frustration-Free Systems
David Gosset, Yichen Huang
Hastings established exponential decay of correlations for ground states of gapped quantum many-body systems. A ground state of a (geometrically) local Hamiltonian with spectral ga…
Efficient simulation of many-body localized systems
Yichen Huang
An efficient numerical method is developed using the matrix product formalism for computing the properties at finite energy densities in one-dimensional (1D) many-body localized (M…
Absence of temporal order in states with spatial correlation decay
Yichen Huang
In quantum lattice systems, we prove that any stationary state with power-law (or even exponential) decay of spatial correlations has vanishing macroscopic temporal order in the th…
Random product states at high temperature equilibrate exponentially well
Yichen Huang
We prove that for all but a measure zero set of local Hamiltonians, starting from random product states at sufficiently high but finite temperature, with overwhelming probability e…
Narrative Incoherence Detection
Deng Cai, Yizhe Zhang, Yichen Huang +2
We propose the task of narrative incoherence detection as a new arena for inter-sentential semantic understanding: Given a multi-sentence narrative, decide whether there exist any…
Two-dimensional local Hamiltonian problem with area laws is QMA-complete
Yichen Huang
We show that the two-dimensional (2D) local Hamiltonian problem with the constraint that the ground state obeys area laws is QMA-complete. We also prove similar results in 2D trans…
Aligning Text-to-Music Evaluation with Human Preferences
Yichen Huang, Zachary Novack, Koichi Saito +5
Despite significant recent advances in generative acoustic text-to-music (TTM) modeling, robust evaluation of these models lags behind, relying in particular on the popular Fréche…
Computing quantum discord is NP-complete
Yichen Huang
We study the computational complexity of quantum discord (a measure of quantum correlation beyond entanglement), and prove that computing quantum discord is NP-complete. Therefore,…
REFeREE: A REference-FREE Model-Based Metric for Text Simplification
Yichen Huang, Ekaterina Kochmar
Text simplification lacks a universal standard of quality, and annotated reference simplifications are scarce and costly. We propose to alleviate such limitations by introducing RE…