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We propose a scheme to engineer an effective spin Hamiltonian starting from a system of electrons confined in micro-Penning traps. By means of appropriate sequences of electromagnetic pulses, alternated to periods of free evolution, we…

Quantum Physics · Physics 2009-11-13 G. Ciaramicoli , I. Marzoli , P. Tombesi

We prove that the quantum Gibbs states of spin systems above a certain threshold temperature are approximate quantum Markov networks, meaning that the conditional mutual information decays rapidly with distance. We demonstrate the…

Quantum Physics · Physics 2020-06-03 Tomotaka Kuwahara , Kohtaro Kato , Fernando G. S. L. Brandão

An emerging trend in approximate counting is to show that certain `low-temperature' problems are easy on typical instances, despite worst-case hardness results. For the class of regular graphs one usually shows that expansion can be…

Data Structures and Algorithms · Computer Science 2024-02-06 Charles Carlson , Ewan Davies , Alexandra Kolla

In this paper we develop a cluster-variant of the Stochastic Series expansion method (SCSE). For certain systems with longer-range interactions the SCSE is considerably more efficient than the standard implementation of the Stochastic…

Condensed Matter · Physics 2009-11-10 Kim Louis , C. Gros

We consider the problem of approximating the free energy density of a translation-invariant, one-dimensional quantum spin system with finite range. While the complexity of this problem is nontrivial due to its close connection to problems…

Quantum Physics · Physics 2024-08-05 Samuel O. Scalet

Simulating quantum circuits (QC) on high-performance computing (HPC) systems has become an essential method to benchmark algorithms and probe the potential of large-scale quantum computation despite the limitations of current quantum…

Interacting spin systems are of fundamental relevance in different areas of physics, as well as in quantum information science, and biology. These spin models represent the simplest, yet not fully understood, manifestation of quantum…

Quantum Physics · Physics 2015-02-27 Johannes Schachenmayer , Alexander Pikovski , Ana Maria Rey

Although spin is a core property in fermionic systems, its symmetry can be easily violated in a variational simulation, especially when strong correlation plays a vital role therein. In this study, we will demonstrate that the broken…

Chemical Physics · Physics 2023-10-09 Takashi Tsuchimochi , Yuto Mori , Seiichiro L. Ten-no

We describe an algorithm for using a quantum computer to calculate mean values of observables and the partition function of a quantum system. Our algorithm includes two sub-algorithms. The first sub-algorithm is for calculating, with…

Quantum Physics · Physics 2010-11-10 Robert R. Tucci

We describe an algorithm that computes the ground state energy and correlation functions for 2-local Hamiltonians in which interactions between qubits are weak compared to single-qubit terms. The running time of the algorithm is polynomial…

Quantum Physics · Physics 2009-11-13 Sergey Bravyi , David DiVincenzo , Daniel Loss

Atomistic spin dynamics (ASD) is a standard tool to model the magnetization dynamics of a variety of materials. The fundamental dynamical model underlying ASD is entirely classical. In this paper, we present two approaches to effectively…

Materials Science · Physics 2024-07-01 Marco Berritta , Stefano Scali , Federico Cerisola , Janet Anders

We present a scalable scheme to design optimized soft pulses and pulse sequences for coherent control of interacting quantum many-body systems. The scheme is based on the cluster expansion and the time dependent perturbation theory…

Quantum Physics · Physics 2007-05-23 Pinaki Sengupta , Leonid P. Pryadko

We discuss a rejectionless global optimization technique which, while being technically similar to the recently introduced method of Extremal Optimization, still relies on a physical analogy with a thermalizing system. Our waiting time…

Statistical Mechanics · Physics 2009-11-07 Jesper Dall , Paolo Sibani

We propose a computationally efficient method to solve the dynamics of operators of bosonic quantum systems coupled to their environments. The method maps the operator under interest to a set of complex-valued functions, and its adjoint…

We study the approximability of computing the partition functions of two-state spin systems. The problem is parameterized by a $2\times 2$ symmetric matrix. Previous results on this problem were restricted either to the case where the…

Computational Complexity · Computer Science 2025-08-19 Yumou Fei , Leslie Ann Goldberg , Pinyan Lu

Quantum algorithms require accurate representations of electronic states on a quantum device, yet the approximation of electronic wave functions for strongly correlated systems remains a profound theoretical challenge, with existing methods…

Quantum Physics · Physics 2025-04-29 Dipanjali Halder , Dibyendu Mondal , Rahul Maitra

We introduce a new method for representing the low energy subspace of a bosonic field theory on the qubit space of digital quantum computers. This discretization leads to an exponentially precise description of the subspace of the…

Quantum Physics · Physics 2018-10-17 Alexandru Macridin , Panagiotis Spentzouris , James Amundson , Roni Harnik

High-fidelity control of quantum systems is essential for scalable quantum technologies. We introduce a shooting-based method which yields smooth control pulses designed to implement gates on discrete quantum systems, and demonstrate its…

Multi-component quantum systems in strong interaction with their environment are receiving increasing attention due to their importance in a variety of contexts, ranging from solid state quantum information processing to the quantum…

Quantum Physics · Physics 2015-03-13 Javier Prior , Alex. W. Chin , Susana. F. Huelga , Martin . B. Plenio

We propose a scheme for the construction of charge and spin linear-response functions of an interacting electronic system via quantum phase estimation and statistical sampling on a quantum computer. By using the unitary decomposition of…

Quantum Physics · Physics 2020-07-15 Taichi Kosugi , Yu-ichiro Matsushita