Quantum fluctuations in the order parameter of quantum skyrmion crystals

Mæland, Kristian; Sudbø, Asle

doi:10.1103/physrevb.105.224416

Cited by 13 publications

(5 citation statements)

References 56 publications

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“…We have truncated at second order in magnons, assuming that the spin fluctuations are weak. This should be a good approximation at low temperatures [33,56,57].…”

Section: Magnonsmentioning

confidence: 91%

“…In Ref. [33], we noted the importance of the four-spin interaction to yield skyrmion states. Here, we treat an MI where we assume the four-spin interaction is negligible.…”

Section: B Magnetic Insulatormentioning

confidence: 99%

“…As in Ref. [33], we tune parameters to get a preferred periodicity using trial states. Then, we use self-consistent iteration [50] to obtain the lowest energy state with that periodicity.…”

Section: B Magnetic Insulatormentioning

confidence: 99%

“…This topological protection is cast into doubt for small skyrmions containing few spins, so-called quantum skyrmions, where the quantum nature of the spins is important. Nevertheless, it is found that quantum fluctuations stabilize skyrmions [33,34]. Additionally, it has been shown that quantum skyrmions display topological magnons [35][36][37].…”

Section: Introductionmentioning

confidence: 99%

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Topological superconductivity mediated by magnons of helical magnetic states

Mæland,

Abnar,

Benestad

et al. 2023

Phys. Rev. B

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We recently showed that spin fluctuations of noncoplanar magnetic states can induce topological superconductivity in an adjacent normal metal [Maeland et al., Phys. Rev. Lett. 130, 156002 (2023)]. The noncolinear nature of the spins was found to be essential for this result, while the necessity of noncoplanar spins was unclear. In this paper we show that magnons in coplanar, noncolinear magnetic states can mediate topological superconductivity in a normal metal. Two models of the Dzyaloshinskii-Moriya interaction are studied to illustrate the need for a sufficiently complicated Hamiltonian describing the magnetic insulator. The Hamiltonian, in particular the specific form of the Dzyaloshinskii-Moriya interaction, affects the magnons and by extension the effective electron-electron interaction in the normal metal. Symmetry arguments are applied to complement this discussion. We solve a linearized gap equation in the case of weak-coupling superconductivity. The result is a time-reversal-symmetric topological superconductor, as confirmed by calculating the topological invariant. In analogy with magnon-mediated superconductivity from antiferromagnets, Umklapp scattering enhances the critical temperature of superconductivity for certain Fermi momenta.

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“…We have truncated at second order in magnons, assuming that the spin fluctuations are weak. This should be a good approximation at low temperatures [33,56,57].…”

Section: Magnonsmentioning

confidence: 91%

“…In Ref. [33], we noted the importance of the four-spin interaction to yield skyrmion states. Here, we treat an MI where we assume the four-spin interaction is negligible.…”

Section: B Magnetic Insulatormentioning

confidence: 99%

“…As in Ref. [33], we tune parameters to get a preferred periodicity using trial states. Then, we use self-consistent iteration [50] to obtain the lowest energy state with that periodicity.…”

Section: B Magnetic Insulatormentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Topological superconductivity mediated by magnons of helical magnetic states

Mæland,

Abnar,

Benestad

et al. 2023

Phys. Rev. B

Self Cite

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“…Formally, this problem can be solved by choosing an appropriate order parameter, a correlation function characterized by a specific non-zero value for the definite range of model parameters. 78,79) However, in this case one faces the problem that different phases cannot be described with a single order parameter. For instance, by using the scalar chirality we cannot distinguish between the cases of zero and high magnetic fields in the considered DMI magnet, Fig.…”

Section: Calculating Inter-scale Dissimilarity Of Bit-string Arraysmentioning

confidence: 99%

Estimating Patterns of Classical and Quantum Skyrmion States

et al. 2023

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In this review we discuss the latest results concerning development of the machine learning algorithms for characterization of the magnetic skyrmions that are topologically-protected magnetic textures originated from the Dzyaloshinskii-Moriya interaction that competes Heisenberg isotropic exchange in ferromagnets. We show that for classical spin systems there is a whole pool of machine approaches allowing their accurate phase classification and quantitative description on the basis of few magnetization snapshots. In turn, investigation of the quantum skyrmions is a less explored issue, since there are fundamental limitations on the simulation of such wave functions with classical supercomputers. One needs to find the ways to imitate quantum skyrmions on near-term quantum computers. In this respect, we discuss implementation of the method for estimating structural complexity of classical objects for characterization of the quantum skyrmion state on the basis of limited number of bitstrings obtained from the projective measurements.

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Skyrmion qubits: Challenges for future quantum computing applications

Psaroudaki,

Peraticos,

Panagopoulos

2023

Applied Physics Letters

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Magnetic nano-skyrmions develop quantized helicity excitations, and the quantum tunneling between nano-skyrmions possessing distinct helicities is indicative of the quantum nature of these particles. Experimental methods capable of nondestructively resolving the quantum aspects of topological spin textures, their local dynamical response, and their functionality now promise practical device architectures for quantum operations. With abilities to measure, engineer, and control matter at the atomic level, nano-skyrmions present opportunities to translate ideas into solid-state technologies. Proof-of-concept devices will offer electrical control over the helicity, opening a promising new pathway toward functionalizing collective spin states for the realization of a quantum computer based on skyrmions. This Perspective aims to discuss developments and challenges in this new research avenue in quantum magnetism and quantum information.

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Quantum fluctuations in the order parameter of quantum skyrmion crystals

Cited by 13 publications

References 56 publications

Topological superconductivity mediated by magnons of helical magnetic states

Topological superconductivity mediated by magnons of helical magnetic states

Estimating Patterns of Classical and Quantum Skyrmion States

Skyrmion qubits: Challenges for future quantum computing applications

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