365 citations · 1.8k across the 43 of their papers we have counts for
43 papers
Large deviations in quantum dynamics and complexity
Xiangyu Cao, Jorge Kurchan
We study three definitions of large deviation in many-body quantum dynamics: (i) via the full distribution of an extensive observable, (ii) via the distribution of measurement outc…
Redundancy from Subsystem Thermalization
Xiangyu Cao, Zohar Nussinov
In the theory of decoherence, redundancy is the correlation between a quantum system and fractions of the environment. It underlies the emergence of classical behavior. We show tha…
Consistent monitoring of quantum fluctuations
Xiangyu Cao
Recent works on the decoherent histories formalism suggested that slow-evolving macroscopic quantities (extensive sums of local observables) in quantum many-body systems can be con…
Planckian bound on quantum dynamical entropy
Xiangyu Cao
We introduce a simplified version of Connes-Narnhofer-Thirring's quantum dynamical entropy for quantum systems. It quantifies the amount of information gained about the initial con…
Stochastic Sampling of Operator Growth Dynamics
Ayush De, Umberto Borla, Xiangyu Cao +1
We put forward a Monte Carlo algorithm that samples the Euclidean time operator growth dynamics at infinite temperature. Crucially, our approach is free from the numerical sign pro…
A Solvable Model of Quantum Darwinism-Encoding Transitions
Benoît Ferté, Xiangyu Cao
We propose a solvable model of Quantum Darwinism to encoding transitions -- abrupt changes in how quantum information spreads in a many-body system under unitary dynamics. We consi…
Surprises in the Deep Hilbert Space of all-to-all systems: From super-exponential scrambling to slow entanglement growth
Zihao Qi, Thomas Scaffidi, Xiangyu Cao
The quantum dynamics of spin systems with uniform all-to-all interaction are often studied in the totally symmetric space (TSS) of maximal total spin. However the TSS states are at…
On the analytical continuation of lattice Liouville theory
Xiangyu Cao, Raoul Santachiara, Romain Usciati
The path integral of Liouville theory is well understood only when the central charge . Here, we study the analytical continuation the lattice Liouville path int…
Operator growth in open quantum systems: lessons from the dissipative SYK
Budhaditya Bhattacharjee, Xiangyu Cao, Pratik Nandy +1
We study the operator growth in open quantum systems with dephasing dissipation terms, extending the Krylov complexity formalism of Phys. Rev. X 9, 041017. Our results are based on…
Clusters in the critical branching Brownian motion
Benoît Ferté, Pierre Le Doussal, Alberto Rosso +1
Brownian particles that are replicated and annihilated at equal rate have strongly correlated positions, forming a few compact clusters separated by large gaps. We characterize the…
Clusters in an epidemic model with long-range dispersal
Xiangyu Cao, Pierre Le Doussal, Alberto Rosso
In presence of long range dispersal, epidemics spread in spatially disconnected regions known as clusters. Here, we characterize exactly their statistical properties in a solvable…
Krylov complexity in saddle-dominated scrambling
Budhaditya Bhattacharjee, Xiangyu Cao, Pratik Nandy +1
In semi-classical systems, the exponential growth of the out-of-timeorder correlator (OTOC) is believed to be the hallmark of quantum chaos. However,on several occasions, it has be…
Quasiparticle kinetic theory for Calogero models
Vir B. Bulchandani, Manas Kulkarni, Joel E. Moore +1
We show that the quasiparticle kinetic theory for quantum and classical Calogero models reduces to the free-streaming Boltzmann equation. We reconcile this simple emergent behaviou…
A statistical mechanism for operator growth
Xiangyu Cao
It was recently conjectured that in generic quantum many-body systems, the spectral density of local operators has the slowest high-frequency decay as permitted by locality. We sho…
Origin and Limit of the Recovery of Damaged Information by Time Reversal
Xiangyu Cao, Thomas Scaffidi
Recently it was found that scrambled information can be partially recovered by a time-reversed evolution, even after being damaged by an intruder. We reconsider the origin of the i…
Dirac Fast Scramblers
Jaewon Kim, Ehud Altman, Xiangyu Cao
We introduce a family of Gross-Neveu-Yukawa models with a large number of fermion and boson flavors as higher dimensional generalizations of the Sachdev-Ye-Kitaev model. The models…
Scrambling versus relaxation in Fermi and non-Fermi liquids
Jaewon Kim, Xiangyu Cao, Ehud Altman
We compute the Lyapunov exponent characterizing quantum scrambling in a family of generalized Sachdev-Ye-Kitaev models, which can be tuned between different low temperature states…
Comment on "Chaotic-Integrable Transition in the Sachdev-Ye-Kitaev Model"
Jaewon Kim, Xiangyu Cao
In arXiv:1707.02197, the authors considered the Sachdev-Ye-Kitaev model with quadratic perturbation (also known as mass-deformed SYK), and claimed that the quantum Lyapunov exponen…
Does scrambling equal chaos?
Tianrui Xu, Thomas Scaffidi, Xiangyu Cao
Focusing on semiclassical systems, we show that the parametrically long exponential growth of out-of-time order correlators (OTOCs), also known as scrambling, does not necessitate…
Low-rank Sachdev-Ye-Kitaev models
Jaewon Kim, Xiangyu Cao, Ehud Altman
Motivated by recent works on atom-cavity realizations of fast scramblers, and on Cooper pairing in non-Fermi liquids, we study a family of solvable variants of the () Sachdev-…
Local Matrix Product Operators: Canonical Form, Compression, & Control Theory
Daniel E. Parker, Xiangyu Cao, Michael P. Zaletel
We present a new method for compressing matrix product operators (MPOs) which represent sums of local terms, such as Hamiltonians. Just as with area law states, such local operator…
The GGE averaged currents of the classical Toda chain
Xiangyu Cao, Vir B. Bulchandani, Herbert Spohn
The Toda chain with random initial data is studied. Of particular interest are generalized Gibbs ensembles, their averaged conserved fields, and the averages of the corresponding c…
Integrable and chaotic dynamics of spins coupled to an optical cavity
Gregory Bentsen, Ionut-Dragos Potirniche, Vir B. Bulchandani +5
We show that a class of random all-to-all spin models, realizable in systems of atoms coupled to an optical cavity, gives rise to a rich dynamical phase diagram due to the pairwise…
Kinetic theory of quantum and classical Toda lattices
Vir B. Bulchandani, Xiangyu Cao, Joel E. Moore
We consider the kinetic theory of the quantum and classical Toda lattice models. A kinetic equation of Bethe-Boltzmann type is derived for the distribution function of conserved qu…