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It is well known that quantum computers are superior to classical computers in efficiently simulating quantum systems. Here we report the first experimental simulation of quantum tunneling through potential barriers, a widespread phenomenon…

Quantum Physics · Physics 2013-10-03 Guan Ru Feng , Yao Lu , Liang Hao , Fei Hao Zhang , Gui Lu Long

We analyze the interference between tunneling paths that occurs for a spin system with both fourth-order and second-order transverse anisotropy. Using an instanton approach, we find that as the strength of the second-order transverse…

Mesoscale and Nanoscale Physics · Physics 2009-04-30 M. S. Foss-Feig , Jonathan R. Friedman

We have studied quantum tunneling of large spins in a biaxial spin system and in a single-axial spin system with a transverse magnetic field. The asymptotically exact eigenvalues and eigenstates of the spin systems are obtained by solving…

Mesoscale and Nanoscale Physics · Physics 2009-10-31 Bambi Hu , De-gang Zhang , Bo-zang Li

Transitions from classical to quantum behaviour in a spin system with two degenerate ground states separated by twin energy barriers which are asymmetric due to an applied magnetic field are investigated. It is shown that these transitions…

Condensed Matter · Physics 2009-10-31 S. -Y. Lee , H. J. W. Mueller-Kirsten , D. K. Park , F. Zimmerschied

Tunneling between the two lowest energy levels of single molecule magnets with Ising type anisotropy, accompanied by the emission or absorption of phonons, is considered. Quantitatively accurate calculations of the rates for such tunneling…

Mesoscale and Nanoscale Physics · Physics 2015-10-05 Yun Liu , Anupam Garg

This article presents a review on the theoretical and the experimental developments on macroscopic quantum tunneling and phase transition of the escape rate in spin systems. We present the basic ideas with simplified calculations so that it…

Other Condensed Matter · Physics 2014-12-18 S. A. Owerre , M. B. Paranjape

We consider transport through a single-molecule magnet strongly coupled to metallic electrodes. We demonstrate that for half-integer spin of the molecule electron- and spin-tunneling \emph{cooperate} to produce both quantum tunneling of the…

Strongly Correlated Electrons · Physics 2009-11-11 C. Romeike , M. R. Wegewijs , W. Hofstetter , H. Schoeller

We introduce a new class of spintronics devices in which a spin-valve like effect results from strong spin-orbit coupling in a single ferromagnetic layer rather than from injection and detection of a spin-polarized current by two coupled…

Mesoscale and Nanoscale Physics · Physics 2009-11-10 C. Gould , C. Rüster , T. Jungwirth , E. Girgis , G. M. Schott , R. Giraud , K. Brunner , G. Schmidt , L. W. Molenkamp

We measure electron tunneling via discrete energy levels in ferromagnetic cobalt particles less than 4 nm in diameter, using non-magnetic electrodes. Due to magnetic anisotropy, the energy of each tunneling resonance shifts as an applied…

Mesoscale and Nanoscale Physics · Physics 2009-10-31 S. Gueron , Mandar M. Deshmukh , E. B. Myers , D. C. Ralph

We demonstrate that transport spectroscopy of single molecular magnets shows signatures of quantum tunneling at low temperatures. We find current and noise oscillations as function of bias voltage due to a weak violation of spin selection…

Strongly Correlated Electrons · Physics 2009-11-11 C. Romeike , M. R. Wegewijs , H. Schoeller

Quantum tunneling from a thin wire or a thin film through a static potential barrier in a zero magnetic field is studied. The wire or the film should satisfy a condition of transverse quantization of levels and be inhomogeneous. Depending…

Quantum Physics · Physics 2008-06-11 B. Ivlev

We show that pure spin injection from a magnetic electrode into an inversion symmetry-broken system composed of a tunnel barrier and a metallic region generates a transverse charge current. Such a tunnelling spin galvanic conversion is…

Mesoscale and Nanoscale Physics · Physics 2023-10-03 Geneviève Fleury , Michael Barth , Cosimo Gorini

Tunneling is an iconic concept that captures the peculiarity of quantum dynamics but, despite its ubiquity, questions remain. We focus on strong-field tunneling, which is vital to all attosecond science. We find an unexpected optical…

Quantum Physics · Physics 2025-04-22 Anne Weber , Margarita Khokhlova , Emilio Pisanty

A novel electromagnetic energy squeezing mechanism is proposed based on the special properties of permeability-near-zero metamaterials. Nearly no energy stream can enter a conventional dielectric region positioned inside a…

Optics · Physics 2015-05-13 Yi Jin , Pu Zhang , Sailing He

A new quantum approach is presented that can account for the description of small ferromagnetic particles magnetization tunneling. An estimate of the saturation value of an external applied magnetic field along the easy axis is obtained. An…

Mesoscale and Nanoscale Physics · Physics 2007-05-23 D. Galetti , B. M. Pimentel , C. L. Lima , E. C. Silva

We revisit the problem of quantum tunneling for a particle moving in the continuum, and in the absence of a magnetic field. In all spatial dimensions, we extend previous results to the case where the single-well potential satisfies…

Mathematical Physics · Physics 2025-06-17 Charles L. Fefferman , Jacob Shapiro , Michael I. Weinstein

We engineer a system of two strongly confined quantum dots to gain reproducible electrostatic control of the spin at zero magnetic field. Coupling the dots in a tight ring-shaped potential with two tunnel barriers, we demonstrate that an…

We present new results on quantum tunneling between deep potential wells, in the presence of a strong constant magnetic field. We construct a family of double well potentials containing examples for which the low-energy eigenvalue splitting…

Mathematical Physics · Physics 2025-01-03 Charles L. Fefferman , Jacob Shapiro , Michael I. Weinstein

This article takes a broad view of the understanding of magnetic bistability and magnetic quantum tunneling in single-molecule magnets (SMMs), focusing on three families of relatively simple, low-nuclearity transition metal clusters: spin S…

A two-interacting-qubit quantum Rabi-like model with vanishing transverse fields on the qubit-pair is studied. Independently of the coupling regime, this model can be exactly and unitarily reduced to two independent single-spin quantum Rabi…

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