We investigate the decoherence and dephasing of two coupled Josephson qubits. With the interaction between the qubits being generated by current-current correlations, two different situations in which the qubits are coupled to the same bath, or to two independent baths, are considered. Upon focussing on dissipation being caused by the fluctuations of voltage sources, the relaxation and dephasin...

We analyze the dephasing effect on the backscattering behavior of the helical surface states in 3D topological insulators. We show that the combination of dephasing and impurity scattering can cause backscattering in the helical states. Especially for the charge impurity case, the backscattering cross section becomes extremely large around the Dirac point. This large backscattering behavior can...

We study high-field spin transport of electrons in a quasi one-dimensional channel of a GaAs gate controlled spin interferometer (SPINFET) using a semiclassical formalism (spin density matrix evolution coupled with Boltzmann transport equation). Spin dephasing (or depolarization) is predominantly caused by D’yakonov-Perel’ relaxation associated with momentum dependent spin orbit coupling effect...

Resonance Raman spectra and absolute Raman scattering intensities of the Franck-Condon coupled vibrational modes of the accessory bacteriochlorophylls (B) in the photosynthetic reaction center from Rb. sphaeroides have been obtained with excitation in their 800 nm Qy absorption band. Although the relative Raman intensities are unchanged when the temperature is reduced from 278 to 95 K, the abso...

In spectroscopy one is always faced with the problem of spectral resolution. One wishes to determine the frequency of the quantized transition with highest accuracy and one is interested in detecting fine structure or neighboring transitions. Disregarding experimental factors, the ultimate resolution is dictated by the inherent linewidth of the transitions. In optical spectroscopy we know vario...

We calculate the dephasing rate of an electron state in a pinched quantum dot, due to Coulomb interactions between the electron in the dot and electrons in a nearby voltage biased ballistic nanostructure. The dephasing is caused by nonequilibrium time fluctuations of the electron density in the nanostructure, which create random electric fields in the dot. As a result, the electron level in the...

We investigate the effect of electron-electron interactions on Aharonov-Bohm (AB) current oscillations in nanorings formed by a chain of metallic quantum dots. We demonstrate that electron-electron interactions cause electron dephasing thereby suppressing the amplitude of AB oscillations at all temperatures down to T = 0. The crossover between thermal and quantum dephasing is found to be contro...