7 papers
Polynomial-time classical and quantum simulation of quantum impurity models
Jiaqing Jiang, Nathan Ju, Ojas Parekh +2
Quantum impurity models are paradigmatic models of interacting quantum matter, as well as key computational primitives for modern electronic-structure methods. They describe a smal…
Lee-Yang theorem for fermions
Chaithanya Rayudu, Takahiro Misawa, Andrew Zhao +1
Lee-Yang theorems are a powerful tool for studying many-body systems, with applications ranging from analyzing phase transitions to proving the efficiency of certain classical and…
Spectral gap of Lee-Yang Hamiltonians
Chaithanya Rayudu, Jun Takahashi
The Lee-Yang theorem and its quantum extensions state that, for a broad class of Hamiltonians on any graph, the partition function's zeros in the complex magnetic field plane lie o…
Fast mixing of operator-loop path-integral quantum Monte Carlo for stoquastic XY Hamiltonians
Chaithanya Rayudu, Jun Takahashi
Quantum Monte Carlo method with operator-loop update is a powerful technique that has been extensively used with great success in condensed matter physics. It enables one to sample…
Fermionic Independent Set and Laplacian of an independence complex are QMA-hard
Chaithanya Rayudu
The Independent Set is a well known NP-hard optimization problem. In this work, we define a fermionic generalization of the Independent Set problem and prove that the optimization…
Constrained local Hamiltonians: quantum generalizations of Vertex Cover
Ojas Parekh, Chaithanya Rayudu, Kevin Thompson
Recent successes in producing rigorous approximation algorithms for local Hamiltonian problems such as Quantum Max Cut have exploited connections to unconstrained classical discret…
An SU(2)-symmetric Semidefinite Programming Hierarchy for Quantum Max Cut
Jun Takahashi, Chaithanya Rayudu, Cunlu Zhou +3
Understanding and approximating extremal energy states of local Hamiltonians is a central problem in quantum physics and complexity theory. Recent work has focused on developing ap…