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We study the quantum tunnel effect through a potential barrier employing a semiclassical formulation of quantum mechanics based on expectation values of configuration variables and quantum dispersions as dynamical variables. The evolution…

Quantum Physics · Physics 2020-12-30 L. Aragon-Muñoz , G. Chacon-Acosta , H. Hernandez-Hernandez

We consider a minisuperspace model for a closed universe with small and positive cosmological constant, filled with a massive scalar field conformally coupled to gravity. In the quantum version of this model, the universe may undergo a…

General Relativity and Quantum Cosmology · Physics 2009-11-07 D. Levkov , C. Rebbi , V. A. Rubakov

We study the quantum propagation of a Skyrmion in chiral magnetic insulators by generalizing the micromagnetic equations of motion to a finite-temperature path integral formalism, using field theoretic tools. Promoting the center of the…

Mesoscale and Nanoscale Physics · Physics 2017-12-05 Christina Psaroudaki , Silas Hoffman , Jelena Klinovaja , Daniel Loss

We use the coherent state approximation for the skyrmion in the isotropic quantum Heisenberg ferromagnet to obtain analytical expression for skyrmion hopping integral as a function of distance. It appears the skyrmion hopping is restricted…

Condensed Matter · Physics 2007-05-23 R. A. Istomin , A. S. Moskvin

Magnetic systems are an exciting realm of study that is being explored on smaller and smaller scales. One extremely interesting magnetic state that has gained momentum in recent years is the skyrmionic state. It is characterized by a vortex…

Mesoscale and Nanoscale Physics · Physics 2013-05-30 Patrick Johnson , A K Gangopadhyay , Ramki Kalyanaraman , Zohar Nussinov

We study the creation of quantum skyrmions in quadratic nanoscopic lattices of quantum spins coupled by Dzyaloshinkii-Moriya and exchange interactions. We numerically show that different kinds of quantum skyrmions, characterized by the…

Mesoscale and Nanoscale Physics · Physics 2022-06-17 Pia Siegl , Elena Y. Vedmedenko , Martin Stier , Michael Thorwart , Thore Posske

The quantum tunneling effects between two metallic plates are studied using the time dependent density functional theory. Results show that the tunneling is mainly dependent on the separation and the initial local field of the interstice…

Mesoscale and Nanoscale Physics · Physics 2015-05-13 Li Mao , Zhipeng Li , Biao Wu , Hongxing Xu

Spin-1 tunneling and splitting of energy levels as a result of tunneling are observed explicitly on IBM's quantum computer, ibmq-bogota. The spin-1 is realized with two spins-1/2. We detect oscillations of spin-1 between the states…

Quantum Physics · Physics 2022-01-25 Kh. P. Gnatenko , V. M. Tkachuk

A new topological excitation called skyrmion has been observed experimentally in chiral magnets without spatial inversion symmetry. The dynamics of a skyrmion is equivalent to an electron moving in a strong magnetic field. As a skyrmion…

Strongly Correlated Electrons · Physics 2013-08-14 Shi-Zeng Lin , Lev N. Bulaevskii

Process of quantum tunneling of particles in various physical systems can be effectively controlled even by a weak and slow varying in time electromagnetic signal if to adapt specially its shape to a particular system. During an…

Quantum Physics · Physics 2009-02-05 B. I. Ivlev

We study the interplay between an inhomogeneous quantum quench of the external potential in a system of relativistic fermions in one dimension and the well-known Klein tunneling. We find that the large time evolution is characterized by…

Statistical Mechanics · Physics 2015-12-25 Leda Bucciantini , Spyros Sotiriadis , Tommaso Macrì

The role of spin polarized reservoirs in quantum tunneling of magnetization and relaxation processes in a single molecular magnet (SMM) is investigated theoretically. The SMM is exchange-coupled to the reservoirs and also subjected to a…

Mesoscale and Nanoscale Physics · Physics 2016-08-16 Maciej Misiorny , Józef Barnas

Coherent and dissipative interactions between different quantum systems are essential for the construction of hybrid quantum systems and the investigation of novel quantum phenomena. Here, we propose and analyze a magnon-skyrmion hybrid…

Quantum Physics · Physics 2024-07-11 Xue-Feng Pan , Peng-Bo Li , Xin-Lei Hei , Xichao Zhang , Masahito Mochizuki , Fu-Li Li , Franco Nori

We have introduced a controllable nano-scale incursion into a potential barrier imposed across a two-dimensional electron gas, and report on the phenomena that we observe as the incursion develops. In the quantum Hall regime, the…

A Mn4 single-molecule magnet (SMM) is used to show that quantum tunneling of magnetization (QTM) is not suppressed by moderate three dimensional exchange coupling between molecules. Instead, it leads to an exchange bias of the quantum…

Mesoscale and Nanoscale Physics · Physics 2009-11-10 R. Tiron , W. Wernsdorfer , N. Aliaga-Alcalde , D. N. Hendrickson , G. Christou

Spin tunneling in molecular magnets has attracted much attention, however theoretical considerations of this phenomenon up to now have not taken into account the many-spin nature of molecular magnets. We present, to our knowledge, the first…

Materials Science · Physics 2009-10-31 M. Al-Saqer , V. V. Dobrovitski , B. N. Harmon , M. I. Katsnelson

Prompted by the longstanding interpretational controversy in quantum mechanics, quantum tunneling is heuristically addressed within the Everettian quantum multiverse. In this framework, the universal wavefunction splits into decohered…

Quantum Physics · Physics 2026-04-28 S. E. Ennadifi

Following our work [Phys. Rev. Lett. 125, 020401 (2020)], we discuss a semiclassical description of one-dimensional quantum tunneling through multibarrier potentials in terms of complex time. We start by defining a complex-extended…

Quantum Physics · Physics 2021-06-09 Pavel Stránský , Milan Šindelka , Pavel Cejnar

The spin relaxation in the molecular magnet \Mn12 is investigated by a novel type of high-frequency magnetic spectroscopy. By reversing the external magnetic field the intensities of the $|\pm 10>\to |\pm 9>$ transitions within the ground…

Strongly Correlated Electrons · Physics 2016-08-31 M. Dressel , B. Gorshunov , K. Rajagopal , S. Vongtragool , A. A. Mukhin

The quantum tunneling of the magnetization vector are studied theoretically in single-domain ferromagnetic nanoparticles placed in an external magnetic field at an arbitrarily directed angle in the $ZX$ plane. We consider the…

Statistical Mechanics · Physics 2009-10-31 Rong Lu , Jia-Lin Zhu , Zhi-Rong Liu , Lee Chang , Bing-Lin Gu