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Related papers: Quantum Merlin Arthur with Exponentially Small Gap

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We study the classical compilation of quantum circuits for the preparation of matrix product states (MPS), which are quantum states of low entanglement with an efficient classical description. Our algorithm represents a near-term…

Quantum Physics · Physics 2026-04-15 Refik Mansuroglu , Norbert Schuch

$ \newcommand{\Xlin}{\mathcal{X}} \newcommand{\Zlin}{\mathcal{Z}} \newcommand{\C}{\mathbb{C}} $We give a quantum multiprover interactive proof system for the local Hamiltonian problem in which there is a constant number of provers,…

Quantum Physics · Physics 2015-12-08 Anand Natarajan , Thomas Vidick

Understanding the entanglement structure of local Hamiltonian ground spaces is a physically motivated problem, with applications ranging from tensor network design to quantum error-correcting codes. To this end, we study the complexity of…

Quantum Physics · Physics 2026-05-29 Sevag Gharibian , Jonas Kamminga

The L1-regularized Gaussian maximum likelihood estimator (MLE) has been shown to have strong statistical guarantees in recovering a sparse inverse covariance matrix, or alternatively the underlying graph structure of a Gaussian Markov…

Machine Learning · Computer Science 2013-06-14 Cho-Jui Hsieh , Matyas A. Sustik , Inderjit S. Dhillon , Pradeep Ravikumar

Proving that the parent Hamiltonian of a Projected Entangled Pair State (PEPS) is gapped remains an important open problem. We take a step forward in solving this problem by showing two results: first, we identify an approximate…

Quantum Physics · Physics 2019-08-29 Michael J. Kastoryano , Angelo Lucia , David Perez-Garcia

We study the complexity of computational problems from quantum physics. Typically, they are studied using the complexity class QMA (quantum counterpart of NP) but some natural computational problems appear to be slightly harder than QMA. We…

Quantum Physics · Physics 2014-04-11 Andris Ambainis

The growing need for uncertainty analysis of complex computational models has led to an expanding use of meta-models across engineering and sciences. The efficiency of meta-modeling techniques relies on their ability to provide…

Numerical Analysis · Mathematics 2016-08-24 Katerina Konakli , Bruno Sudret

The Polynomial-Time Hierarchy ($\mathsf{PH}$) is a staple of classical complexity theory, with applications spanning randomized computation to circuit lower bounds to ''quantum advantage'' analyses for near-term quantum computers.…

Computational Complexity · Computer Science 2024-09-04 Avantika Agarwal , Sevag Gharibian , Venkata Koppula , Dorian Rudolph

A Hamiltonian is said to be quasi-exactly solvable (QES) if some of the energy levels and the corresponding eigenfunctions can be calculated exactly and in closed form. An entirely new class of QES Hamiltonians having sextic polynomial…

Quantum Physics · Physics 2009-11-11 Carl M. Bender , Maria Monou

Real-space renormalization approaches for quantum lattice systems generate certain hierarchical classes of states that are subsumed by the multi-scale entanglement renormalization ansatz (MERA). It is shown that, with the exception of one…

Quantum Physics · Physics 2010-07-16 Thomas Barthel , Martin Kliesch , Jens Eisert

We describe an efficient approximation algorithm for evaluating the ground-state energy of the classical Ising Hamiltonian with linear terms on an arbitrary planar graph. The running time of the algorithm grows linearly with the number of…

Quantum Physics · Physics 2009-09-16 Nikhil Bansal , Sergey Bravyi , Barbara M. Terhal

We introduce a simple sub-universal quantum computing model, which we call the Hadamard-classical circuit with one-qubit (HC1Q) model. It consists of a classical reversible circuit sandwiched by two layers of Hadamard gates, and therefore…

Quantum Physics · Physics 2018-11-19 Tomoyuki Morimae , Yuki Takeuchi , Harumichi Nishimura

We propose a quantum authentication and digital signature protocol whose security is founded on the Quantum Merlin Arthur~(QMA)-completeness of the consistency of local density matrices. The protocol functions as a true public-key…

Quantum Physics · Physics 2025-06-23 Le-Ran Liu , Min-Quan He , Dan-Bo Zhang , Z. D. Wang

In this paper, we study the integrality gap of the Knapsack linear program in the Sherali- Adams and Lasserre hierarchies. First, we show that an integrality gap of 2 - {\epsilon} persists up to a linear number of rounds of Sherali-Adams,…

Computational Complexity · Computer Science 2010-07-09 Anna R. Karlin , Claire Mathieu , C. Thach Nguyen

Characterizing the entanglement structure of ground states of local Hamiltonians is a fundamental problem in quantum information. In this work we study the computational complexity of this problem, given the Hamiltonian as input. Our main…

Quantum Physics · Physics 2024-11-08 Adam Bouland , Chenyi Zhang , Zixin Zhou

Efficient encoding of classical information plays a fundamental role in numerous practical quantum algorithms. However, the preparation of an arbitrary amplitude-encoded state has been proven to be time-consuming, and its deployment on…

Quantum Physics · Physics 2025-08-19 Chao Wang , Pengrui Zhou , Xi-Ning Zhuang , Ziwei Cui , Menghan Dou , Zhao-Yun Chen , Guo-Ping Guo

The concept of promise problems was introduced and started to be systematically explored by Even, Selman, Yacobi, Goldreich, and other scholars. It has been argued that promise problems should be seen as partial decision problems and as…

Formal Languages and Automata Theory · Computer Science 2015-12-09 Shenggen Zheng , Lvzhou Li , Daowen Qiu , Jozef Gruska

This paper presents the following results on sets that are complete for NP. 1. If there is a problem in NP that requires exponential time at almost all lengths, then every many-one NP-complete set is complete under length-increasing…

Computational Complexity · Computer Science 2010-02-03 Xiaoyang Gu , John M. Hitchcock , A. Pavan

The Acceptance Probability Estimation Problem (APEP) is to additively approximate the acceptance probability of a Boolean circuit. This problem admits a probabilistic approximation scheme. A central question is whether we can design a…

Computational Complexity · Computer Science 2021-03-16 Peter Dixon , A. Pavan , N. V. Vinodchandran

In this article we introduce a new complexity class called PQMA_log(2). Informally, this is the class of languages for which membership has a logarithmic-size quantum proof with perfect completeness and soundness which is polynomially close…

Quantum Physics · Physics 2016-11-25 Hugue Blier , Alain Tapp