Related papers: Simple Calculation of Quantum Spin Tunneling Effec…
Based on phase space arguments, we develop a simple approach to metallic quantum critical points, designed to study the problem without integrating the fermions out of the partition function. The method is applied to the spin-fermion model…
The paper studies spin-orbit interaction (i.e. the effect the spin has on the particle's trajectory in a magnetic field) as a model of quantum computation. The two-level spin quantum system is examined using the stochastic mechanics…
A discrete WKB method is developed for calculating tunnel splittings in spin problems. The method is then applied to the issue of how nuclear spins affect the macroscopic quantum coherence of the total magnetic moment in small magnetic…
We derive a semiclassical formula for the tunneling current of electrons trapped in a potential well which can tunnel into and across a wide quantum well. The calculations idealize an experimental situation where a strong magnetic field…
Recent experiments are reviewed that explore the spin states of a ring-shaped many-electron quantum dot. Coulomb-blockade spectroscopy is used to access the spin degree of freedom. The Zeeman effect observed for states with successive…
We study the Kondo effect in a quantum dot coupled to two noncollinear ferromagnetic leads. First, we study the spin splitting $\delta\epsilon=\epsilon_{\downarrow}-\epsilon_{\uparrow}$ of an energy level in the quantum dot by tunnel…
A mesoscopic spin valve is used to determine the effective spin polarization of electrons tunneling from and into ferromagnetic transition metals at finite voltages. The tunneling spin polarization from the ferromagnet (FM) slowly decreases…
The double-well potential is a good example, where we can compute the splitting in the bound state energy of the system due to the tunneling effect with various methods, namely WKB or instanton calculations. All these methods are…
Spin dependent single electron tunneling in ferromagnetic double junctions is analysed theoretically in the limit of sequential tunneling. The influence of discrete energy spectrum of the central electrode (island)on the spin accumulation,…
The tunneling effect is the most popular phenomenon of quantum physics and is present in modern physical theories. Still, the most important features of this effect are already present in toy models - low dimensional quantum mechanics with…
Electron tunneling in ferromagnetic single-electron transistors is considered theoretically in the sequential tunneling regime. A new formalism is developed, which operates in a two-dimensional space of states, instead of one-dimensiona…
We theoretically study the effects of bias-controlled interdot tunneling in vertically coupled quantum dots on the emission properties of spin excitons in various bias-controlled tunneling regimes. As a main result, for strongly coupled…
We demonstrate how rate equations can be employed to find analytical expressions for the sequential tunneling current through a quantum dot as a function of the tunnel rates, for an arbitrary number of states involved. We apply this method…
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…
Small ferromagnets and anti-ferromagnets with an easy-plane anisotropy have a ground to first excited state (tunnel) splitting which is quasi-periodic in the magnitude of a field applied perpendicular to a principal anisotropy axis. The…
Quasiparticle interference patterns measured by scanning tunneling microscopy (STM) can be used to study the local electronic structure of metal surfaces and high temperature superconductors. Here, we show that even in non-magnetic systems…
The equal-interval splitting of quantum tunneling observed in simple-Ising-model systems of Ni$_{4}$ (3D) and Mn$_3$ (2D) single-molecule magnets (SMMs) is reported. The splitting is due to the identical exchange coupling in the SMMs, and…
Quantum dot spin valves are characterized by exchange fields which induce spin precession and generate current spin resonances even in absence of spin splitting. Analogous effects have been studied in double quantum dots, in which the…
Starting from a phenomenological Hamiltonian originally written in terms of angular momentum operators we derive a new quantum angle-based Hamiltonian that allows for a discussion on the quantum spin tunneling. The study of the…
Plasmas are usually described using classical equations. While this is often a good approximation, where are situations when a quantum description is motivated. In this paper we will include several quantum effects, ranging from particle…