Exploring instantons in nonlinear sigma models with spin-lattice systems

Schenk, S.; Spannowsky, Michael

doi:10.1103/physrevb.103.144436

Cited by 6 publications

(3 citation statements)

References 68 publications

(98 reference statements)

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“…QA has been utilized in many simple settings, notably for solving network problems, but its application in high energy theory has up to now been somewhat limited (see refs. [21–35] for some examples). In the string setting, QA has been employed in hybrid algorithms, for example, most recently in Genetic QA [ 33,34 ] in which the GA performance is improved with a QA stage, however it has not to date been possible to implement a full string search directly on a quantum annealer (or indeed on a quantum computer of any kind).…”

Section: Introductionmentioning

confidence: 99%

String Model Building on Quantum Annealers

Abel,

Nutricati,

Rizos

2023

Fortschritte der Physik

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For the first time the direct construction of string models on quantum annealers has been explored and has been investigated their efficiency and effectiveness in the model discovery process. Through a thorough comparison with traditional methods such as simulated annealing, random scans, and genetic algorithms, it is highlighted the potential advantages offered by quantum annealers, which in this study promised to be roughly 50 times faster than random scans and genetic algorithm and approximately four times faster than simulated annealing.

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Section: Introductionmentioning

confidence: 99%

String Model Building on Quantum Annealers

Abel,

Nutricati,

Rizos

2023

Fortschritte der Physik

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“… 16 – 18 ). In particular, Monte Carlo (MC) simulations have been proved to be a powerful tool in this endeavor 7 , 19 ; more generally, MC simulations have been successfully used to study topological solitons in quantum field theories 20 , 21 . For the example of chiral magnets, MC techniques enabled demonstrating that the combination of ferromagnetic exchange and DM interactions is sufficient to reproduce the experimentally-determined finite-temperature phase diagram, featuring a stable skyrmion pocket 22 .…”

Section: Introductionmentioning

confidence: 99%

Simulating anti-skyrmions on a lattice

Criado

Schenk

Spannowsky

et al. 2022

Sci Rep

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Magnetic skyrmions are meta-stable spin structures that naturally emerge in magnetic materials. While a vast amount of effort has gone into the study of their properties, their counterpart of opposite topological charge, the anti-skyrmion, has not received as much attention. We aim to close this gap by deploying Monte Carlo simulations of spin-lattice systems in order to investigate which interactions support anti-skyrmions, as well as skyrmions of Bloch and Néel type. We find that the combination of ferromagnetic exchange and Dzyaloshinskii–Moriya (DM) interactions is able to stabilize each of the three types, depending on the specific structure of the DM interactions. Considering a three-dimensional spin lattice model, we provide a finite-temperature phase diagram featuring a stable anti-skyrmion lattice phase for a large range of temperatures. In addition, we also shed light on the creation and annihilation processes of these anti-skyrmion tubes and study the effects of the DM interaction strength on their typical size.

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“…In finance, quantitative optimisation of portfolios can yield increased profitability [5,6,7]. And in physics, the scope of applications ranges from complex systems in classical mechanics [8], through quantum mechanics [9,10,11,12] and condensed matter systems [13,14,15,16,17] all the way to models in string theory [18,19,20,21,22] and high-energy physics [23,24,25,26,27]. Further, broad classes of mathematical problems, for example finding the solution to a differential equation [28,29,30], can by variational methods be rephrased as an optimisation task that ultimately corresponds to finding the extremum of a complicated system.…”

Section: Introductionmentioning

confidence: 99%

Quantum Optimisation of Complex Systems with a Quantum Annealer

Abel,

Blance,

Spannowsky

2021

Preprint

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We perform an in-depth comparison of quantum annealing with several classical optimisation techniques, namely thermal annealing, Nelder-Mead, and gradient descent. We begin with a direct study of the 2D Ising model on a quantum annealer, and compare its properties directly with those of the thermal 2D Ising model. These properties include an Ising-like phase transition that can be induced by either a change in "quantum-ness" of the theory (by way of the transverse field component on the annealer), or by a scaling the Ising couplings up or down. This behaviour is in accord with what is expected from the physical understanding of the quantum system. We then go on to demonstrate the efficacy of the quantum annealer at minimising several increasingly hard two dimensional potentials. For all the potentials we find the general behaviour that Nelder-Mead and gradient descent methods are very susceptible to becoming trapped in false minima, while the thermal anneal method is somewhat better at discovering the true minimum. However, and despite current limitations on its size, the quantum annealer performs a minimisation very markedly better than any of these classical techniques. A quantum anneal can be designed so that the system almost never gets trapped in a false minimum, and rapidly and successfully minimises the potentials.

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Exploring instantons in nonlinear sigma models with spin-lattice systems

Cited by 6 publications

References 68 publications

String Model Building on Quantum Annealers

String Model Building on Quantum Annealers

Simulating anti-skyrmions on a lattice

Quantum Optimisation of Complex Systems with a Quantum Annealer

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