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Simulating strongly correlated fermionic systems is notoriously hard on classical computers. An alternative approach, as proposed by Feynman, is to use a quantum computer. Here, we discuss quantum simulation of strongly correlated fermionic…

Quantum Physics · Physics 2018-05-02 Zhang Jiang , Kevin J. Sung , Kostyantyn Kechedzhi , Vadim N. Smelyanskiy , Sergio Boixo

A novel scheme is presented for generation of a multipartite W state for arbitrary number of qubits. Based on a recent proposal of entanglement without touching, it serves to demonstrate the potential of particle indistinguishability as a…

Quantum Physics · Physics 2021-08-05 Pawel Blasiak , Ewa Borsuk , Marcin Markiewicz , Yong-Su Kim

This work proposes a protocol for Fermionic Hamiltonian learning. For the Hubbard model defined on a bounded-degree graph, the Heisenberg-limited scaling is achieved while allowing for state preparation and measurement errors. To achieve…

Quantum Physics · Physics 2024-05-03 Hongkang Ni , Haoya Li , Lexing Ying

Using exact continuous quantum Monte Carlo techniques, we study the zero and finite temperature properties of a system of harmonically trapped one dimensional spin 1/2 fermions with short range interactions. Motivated by experimental…

Other Condensed Matter · Physics 2009-11-13 Michele Casula , D. M. Ceperley , Erich J. Mueller

A method is presented for tracing the locus of a specific peak in the frequency response under variation of a parameter. It is applicable to periodic, steady-state vibrations of harmonically forced nonlinear mechanical systems. It operates…

Computational Engineering, Finance, and Science · Computer Science 2021-01-01 Alwin Förster , Malte Krack

We discuss several methods for unambiguous state discrimination of N symmetric coherent states using linear optics and photodetectors. One type of measurements is shown to be optimal in the limit of small photon numbers for any N. For the…

Quantum Physics · Physics 2009-11-07 S. J. van Enk

Extracting meaningful information about unknown quantum states without performing a full tomography is an important task. Low-dimensional projections and random measurements can provide such insight but typically require careful crafting.…

Quantum state tomography, a fundamental tool for quantum physics, usually requires a number of state copies that scale exponentially with the system size, owing to the intricate quantum correlations between subsystems. We show that, in…

Quantum Physics · Physics 2025-12-22 Xiaobin Zhao , Pengcheng Liao , Francesco Anna Mele , Ulysse Chabaud , Quntao Zhuang

We propose a measure of interaction-induced ground state entanglement in many-fermion systems that is experimentally accessible. It is formulated in terms of cross-correlations of currents through resonant fermion levels weakly coupled to…

Quantum Physics · Physics 2009-11-11 M. Kindermann

We give a quasi-polynomial time classical algorithm for estimating the ground state energy and for computing low energy states of quantum impurity models. Such models describe a bath of free fermions coupled to a small interacting subsystem…

Quantum Physics · Physics 2018-10-23 Sergey Bravyi , David Gosset

We theoretically demonstrate a method for producing the maximally path-entangled state (1/Sqrt[2]) (|N,0> + exp[iN phi] |0,N>) using intensity-symmetric multiport beamsplitters, single photon inputs, and either photon-counting postselection…

Quantum Physics · Physics 2008-11-26 G. J. Pryde , A. G. White

We consider the Reinforcement Learning problem of controlling an unknown dynamical system to maximise the long-term average reward along a single trajectory. Most of the literature considers system interactions that occur in discrete time…

Artificial Intelligence · Computer Science 2023-09-07 Lorenzo Croissant , Marc Abeille , Bruno Bouchard

In this work we present a detailed study of the Fermion Monte Carlo algorithm (FMC), a recently proposed stochastic method for calculating fermionic ground-state energies [M.H. Kalos and F. Pederiva, Phys. Rev. Lett. vol. 85, 3547 (2000)].…

Strongly Correlated Electrons · Physics 2009-11-11 Roland Assaraf , Michel Caffarel , Anatole Khelif

To analyze quantum many-body Hamiltonians, recently, machine learning techniques have been shown to be quite useful and powerful. However, the applicability of such machine learning solvers is still limited. Here, we propose schemes that…

Strongly Correlated Electrons · Physics 2020-04-17 Yusuke Nomura

By removing one empty site between two occupied sites, we map the ground states of chains of hardcore bosons and spinless fermions with infinite nearest-neighbor repulsion to ground states of chains of hardcore bosons and spinless fermions…

Strongly Correlated Electrons · Physics 2015-05-13 Siew-Ann Cheong , Christopher L. Henley

We present an optimal quantum algorithm for fidelity estimation between two quantum states when one of them is pure. In particular, the (square root) fidelity of a mixed state to a pure state can be estimated to within additive error…

Quantum Physics · Physics 2025-10-03 Wang Fang , Qisheng Wang

For a class of translation-invariant free-fermion systems (including those with uniform nearest neighbor hopping) on a $d$-dimensional $L \times \cdots \times L$ hypercubic lattice, we prove that, starting from an arbitrary pure initial…

Mathematical Physics · Physics 2026-02-17 Takashi Hara , Tatsuhiko Koike

Quantum master equations are common tools to describe the dynamics of many-body systems open to an environment. Due to the interaction with the latter, even for the case of non-interacting electrons, the computational cost to solve these…

Other Condensed Matter · Physics 2009-09-29 Yu. V. Pershin , Y. Dubi , M. Di Ventra

Entanglement measures constitute powerful tools in the quantitative description of quantum many-body systems out of equilibrium. We study entanglement in the current-carrying steady state of a paradigmatic one-dimensional model of…

Quantum Physics · Physics 2023-10-30 Shachar Fraenkel , Moshe Goldstein

We present a non-perturbative, mean-field theory for the Fermi-Pasta-Ulam-Tsingou model with quartic interaction, capturing the quasiperiodic features shown by the system at all energies in the thermodynamic limit. Starting from the true…

Statistical Mechanics · Physics 2025-12-02 Antonio Ponno , Giacomo Gradenigo , Marco Baldovin , Angelo Vulpiani