Inelastic spin relaxation and spin splitting epsilon(s) in lateral quantum dots are studied in the regime of strong in-plane magnetic field. Because of both the g-factor energy dependence and spin-orbit coupling, epsilon(s) demonstrates a substantial nonlinear magnetic field dependence similar to that observed by Hanson et al. [Phys. Rev. Lett. 91, 196802 (2003)]. It also varies with the in-pla...

Strain-induced gradients of local electric fields in semiconductor quantum dots can couple to the quadrupole moments of nuclear spins. We develop a theory describing the influence of this quadrupolar coupling on the spin correlators of electron and hole "central" spins localized in such dots. We show that when the quadrupolar coupling strength is comparable to or larger than the hyperfine coupl...

The back action of typical macroscopic resonators used for detecting nuclear magnetic resonance can cause a reversible decay of the signal, known as radiation damping. A mechanical resonator that is strongly coupled to a microscopic sample can in addition induce an irreversible dissipation of the nuclear-spin signal, distinct from radiation damping. We provide a theoretical description of reson...

Measurements have been carried out in six subjects at magnetic fields of 1.5, 3 and 7 T, with the aim of characterizing the variation of T2* with field strength in human brain. Accurate measurement of T2* in the presence of macroscopic magnetic field inhomogeneity is problematic due to signal decay resulting from through-slice dephasing. The approach employed here allowed the signal decay due t...

Introduction: For patients with transfusional iron overload, improved noninvasive methods for monitoring iron-chelating therapy are needed. MRI provides a means to non-invasively assess tissue iron concentration in both liver and heart by exploiting the paramagnetic effects of iron on the relaxation rates of solvent protons, such as R1, R2, or R2 . At present, the most widely used method is bre...

Introduction Correlation of quantitative MRI with brain iron may provide a useful tool in the diagnosis and prognosis of neuropathology such as Multiple Sclerosis, Alzheimer’s and Parkinson’s Disease. Several different MR measures of brain iron have been proposed ([1] and references therein). The aim of this work was to compare three of the most promising, namely: transverse relaxation rate, ma...

The water proton spin-spin (transverse) relaxation rate of chloroplast suspensions has been measured after each of a series of 2.4 musec light flashes. The sequence of relaxation rates shows a damped oscillatory pattern with a period of four and peaks after the 3rd, 7th, 11th, and 15th flashes. This result indicates that water proton relaxation can be used to monitor the charge-accumulating sta...

The weakly bending rod (WBR) model of double-stranded DNA (dsDNA) is adapted to analyze the internal dynamics of dsDNA as observed in electron paramagnetic resonance (EPR) measurements of the spin-lattice relaxation rate, R(1e), for spin probes rigidly attached to nucleic acid-bases. The WBR theory developed in this work models dsDNA base-pairs as diffusing rigid cylindrical discs connected by ...

Recent and ongoing optical experiments on mechanisms and methods for control and gating of spin relaxation in semiconductor quantum wells are reviewed. We discuss work on high-mobility two-dimensional electron gases in (001)-grown GaAs/AlGaAs wells which reveals two new aspects of D’yakonov, Perel’ and Kachorovskii (DPK) spin dynamics, namely oscillatory spin evolution in a quasi-collision-free...