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Nonlocal correlation represents the key feature of quantum mechanics, and is an exploitable resource in quantum information processing. However, the loophole issues and the associated applicability compromises hamper the practical…

Quantum Physics · Physics 2026-04-29 Qiang Zeng , Huihong Yuan , Haoyang Wang , Lai Zhou , Zhiliang Yuan

Using the density matrix renormalization group algorithm, we study the model of spinless fermions with nearest-neighbor interaction on a ring in the presence of disorder. We determine the spatial decay of the density induced by a defect…

Condensed Matter · Physics 2009-10-28 P. Schmitteckert , U. Eckern

We give a detailed account of an efficient search algorithm for the data pattern tomography proposed by J. Rehacek, D. Mogilevtsev, and Z. Hradil [Phys. Rev. Lett.~\textbf{105}, 010402 (2010)], where the quantum state of a system is…

We construct entanglement renormalization schemes which provably approximate the ground states of non-interacting fermion nearest-neighbor hopping Hamiltonians on the one-dimensional discrete line and the two-dimensional square lattice.…

We show with explicit formulas that one can completely identify an unknown quantum process with only one weakly entangled state; and identify a quantum optical Gaussian process with either one two-mode squeezed state or a few different…

Quantum Physics · Physics 2010-10-05 Xiang-Bin Wang , J. -Z. Hu , Z. -W. Yu , Franco Nori

Out-of-equilibrium states of many-body systems tend to evade a description by standard statistical mechanics, and their uniqueness is epitomized by the possibility of certain long-range correlations that cannot occur in equilibrium. In…

Quantum Physics · Physics 2024-04-02 Shachar Fraenkel , Moshe Goldstein

Trace distance and infidelity (induced by square root fidelity), as basic measures of the closeness of quantum states, are commonly used in quantum state discrimination, certification, and tomography. However, the sample complexity for…

Quantum Physics · Physics 2024-10-29 Qisheng Wang , Zhicheng Zhang

High fidelity state preparation represents a fundamental challenge in the application of quantum technology. While the majority of optimal control approaches use feedback to improve the controller, the controller itself often does not…

Quantum Physics · Physics 2021-11-22 Ethan N. Evans , Ziyi Wang , Adam G. Frim , Michael R. DeWeese , Evangelos A. Theodorou

Tasks such as classification of data and determining the groundstate of a Hamiltonian cannot be carried out through purely unitary quantum evolution. Instead, the inherent non-unitarity of the measurement process must be harnessed.…

Quantum Physics · Physics 2023-04-24 Lewis Wright , Fergus Barratt , James Dborin , George H. Booth , Andrew G. Green

We extract the leading effective range corrections to the equation of state of the unitary Fermi gas from ab initio fixed-node quantum Monte Carlo (FNQMC) calculations in a periodic box using a density functional theory (DFT), and show them…

Quantum Gases · Physics 2012-11-16 Michael McNeil Forbes , Stefano Gandolfi , Alexandros Gezerlis

The problem of unambiguously distinguishing among nonorthogonal but linearly independent quantum states can be solved by mapping the set of nonorthogonal quantum states onto a set of orthogonal ones, which can then be distinguished without…

Quantum Physics · Physics 2009-11-06 Yuqing Sun , Mark Hillery , Janos Bergou

We consider the problem of quantum state certification, where one is given $n$ copies of an unknown $d$-dimensional quantum mixed state $\rho$, and one wants to test whether $\rho$ is equal to some known mixed state $\sigma$ or else is…

Quantum Physics · Physics 2017-11-07 Costin Bădescu , Ryan O'Donnell , John Wright

We propose convenient inferential methods for potentially nonstationary multivariate unobserved components models with fractional integration and cointegration. Based on finite-order ARMA approximations in the state space representation,…

Econometrics · Economics 2020-11-10 Tobias Hartl , Roland Weigand

We have developed an efficient simulation algorithm for strongly interacting relativistic fermions in two-dimensional field theories based on a formulation as a loop gas. The loop models describing the dynamics of the fermions can be mapped…

High Energy Physics - Lattice · Physics 2009-11-05 Urs Wenger

We develop a scheme to distill entanglement from bipartite Fermionic systems in an arbitrary quasifree state. It can be applied if either one system containing infinite one-copy entanglement is available or if an arbitrary amount of equally…

Quantum Physics · Physics 2015-03-13 Zoltan Kadar , Michael Keyl , Dirk Schlingemann

The area of sublinear algorithms have recently received a lot of attention. In this setting, one has to choose specific access model for the input, as the algorithm does not have time to pre-process or even to see the whole input. A…

Data Structures and Algorithms · Computer Science 2020-09-24 Jakub Tětek

The algorithmic tasks of computing the Hamming distance between a given pattern of length $m$ and each location in a text of length $n$ is one of the most fundamental algorithmic tasks in string algorithms. Unfortunately, there is evidence…

Data Structures and Algorithms · Computer Science 2015-12-15 Tsvi Kopelowitz , Ely Porat

In machine learning and particularly in topological data analysis, $\epsilon$-graphs are important tools but are generally hard to compute as the distance calculation between n points takes time O(n^2) classically. Recently, quantum…

Data Structures and Algorithms · Computer Science 2023-06-08 Naomi Mona Chmielewski , Nina Amini , Paulin Jacquot , Joseph Mikael

Efficient characterization of highly entangled multi-particle systems is an outstanding challenge in quantum science. Recent developments have shown that a modest number of randomized measurements suffices to learn many properties of a…

Quantum Physics · Physics 2022-12-13 Katherine Van Kirk , Jordan Cotler , Hsin-Yuan Huang , Mikhail D. Lukin

Measurement-based quantum computation, an alternative paradigm for quantum information processing, uses simple measurements on qubits prepared in cluster states, a class of multiparty entangled states with useful properties. Here we propose…

Quantum Physics · Physics 2019-05-01 Mikhail Mamaev , Rainer Blatt , Jun Ye , Ana Maria Rey