Search results for "spin [structure function]"

Exact dynamics of XX central spin models

2009

The dynamical behavior of a star network of spins, wherein each of N decoupled spins interact with a central spin through non uniform Heisenberg XX interaction is exactly studied. The time-dependent Schrodinger equation of the spin system model is solved starting from an arbitrary initial state. The resulting solution is analyzed and briefly discussed.

Instantaneous diffusion effect on spin-echo decay: Experimental investigation by spectral selective excitation

2001

The influence of the instantaneous diffusion process on spin-echo decay of ${E}_{\ensuremath{\gamma}}^{\ensuremath{'}}$ centers in gamma irradiated silica is experimentally probed by spectral selective excitation within their inhomogeneous resonance line. Our results evidence the different effectiveness of this dephasing mechanism on varying the resonance field, manifesting itself by a faster decay of the echo signal when generated by spin packets located in the central part of the spectrum. It is shown that the dependence of the instantaneous diffusion rate on the spectral position of echo-active spins reproduces the shape of the ${E}_{\ensuremath{\gamma}}^{\ensuremath{'}}$ centers resonan…

Spin-echo entanglement protection from random telegraph noise

2014

We analyze local spin-echo procedures to protect entanglement between two non-interacting qubits, each subject to pure-dephasing random telegraph noise. For superconducting qubits this simple model captures characteristic features of the effect of bistable impurities coupled to the device. An analytic expression for the entanglement dynamics is reported. Peculiar features related to the non-Gaussian nature of the noise already observed in the single qubit dynamics also occur in the entanglement dynamics for proper values of the ratio $g=v/\gamma$, between the qubit-impurity coupling strength and the switching rate of the random telegraph process, and of the separation between the pulses $\D…

New features in systematics of low-spin states in even106?120Cd

1990

Low- spin states in even106–112Cd and116Cd were investigated by in-beam and off-beam γ-ray and conversion electron spectroscopy. New spin assignments and decay branching ratios for the levels in106Cd,108Cd and110Cd were obtained. From the new systematical data for the even106–120Cd, it is inferred that two sets of low-lying 0+ states cross between114Cd and116Cd. One of these sets appears to have features of both intruder and two-quadrupole-phonon states.

Spin current pumping in helical Luttinger liquids

2013

We study the DC spin current induced into an unbiased quantum spin Hall system through a two-point contacts setup with time dependent electron tunneling amplitudes. By means of two external gates, it is possible to drive a current with spin-preserving and spin-flipping contributions showing peculiar oscillations as a function of pumping frequency, electron-electron interaction and temperature. From its interference patterns as a function of the Fabry-Perot and Aharonov-Bohm phases, it is possible to extract information about the helical nature of the edge states and the intensity of the electron-electron interaction.

Spin Crossover, Liesst, and Niesst-Fascinating Electronic Games in Iron Complexes

1997

Abstract Coordination compounds of transition metal ions with open-shell electron configurations may exhibit dynamic electronic structure phenomena depending on the nature of the coordinating ligand sphere. The change of spin state with temperature (thermal spin crossover”) and light-induced electron transfer processes leading to long-lived metastable states are among the most fascinating electronic games encountered in transition metal compounds and are presently under intensive study by chemists and physicists. The first part of this lecture will survey briefly some highlights of previous work and present recent results on thermal spin crossover in iron(II) compounds. The second part of t…

Study of Intermediate-spin States of $^{98}$Y

2015

The nuclear structure of the odd–odd nucleus 98Y has been re-investigated by observing prompt γ rays emitted following the proton-induced fission of a 238U target, using the JUROGAM-II multidetector array. New highspin decays have been observed and placed in the level schemes using triple coincidences. The experimental level energies and γ-decay patterns are compared to GICM and QPRM calculations, assuming that this neutronrich N = 59 isotone is spherical at low energies and prolate deformed at intermediate spins. Web of Science 47 3 916 911

ELECTRON SPIN RESONANCE AND ELECTROCHEMICAL STUDIES OF OXIDATION PRODUCTS DERIVATES OF APOMORPHINE IN APROTIC SOLVENTS

2002

Apomorphine acts as contractile muscular agent through an extra cellular calcium mechanism dependent. This activity is accompanied with autoxidación process producing o-quinone derivates. o-Quinone is also obtained by apomorphine oxidation in acid medium; in basic conditions a hydroxi-p-quinone is formed. In order to characterize the apomorphine derivates species generated via metabolism or chemical mechanism, specially free radical forms, electrochemical and Electronic Spin Resonance studies were done to o and p-quinones metabolites in presence or absence of Calcium ions. The electrochemical study of these compounds using cyclic voltametric indicated that the reduction mechanism consists o…

Quantum Einstein Gravity: Towards an Asymptotically Safe Field Theory of Gravity

2007

Quantum Criticality of Spin Liquids in Novel Insulators and Magnets

2014

Strongly correlated Fermi systems are among the most intriguing and fundamental systems in physics, whose realization in some compounds is still under consideration. Quantum spin liquids are a promising new phases, where exotic quantum states of matter could be realized. Exotic quantum spin liquid (QSL) made of such hypothetic particles as fermionic spinons which carry spin \(1/2\) and no charge are considered in this chapter. Magnetic insulators with geometrical frustration produce important experimental facts shedding light on the nature of quantum spin liquid composed of spinons. We present a theory of the thermodynamic properties of quantum spin liquids, elucidating how their properties…