The quantum dynamics of a two-state system coupled to a bosonic reservoir with sub-Ohmic spectral density is investigated for strong friction. Numerically exact path integral Monte Carlo methods reveal that a changeover from coherent to incoherent relaxation does not occur for a broad class of spectral distributions. In nonequilibrium coherences associated with substantial system-reservoir enta...

The line width dependence of zero-phonon lines and phonon sidebands on temperature, bath dissipation, and electron-phonon coupling is studied for an underdamped Brownian oscillator model with an Ohmic dissipative bath. Factors determining the line widths vary from the zero-phonon lines to the phonon sidebands. The control-parameter space of line broadening has been mapped out, revealing that th...

The kinematic evolution of axisymmetric magnetic and electric elds near a rotating black hole is investigated numerically in Kerr geometry. In the cases investigated it is found that a magnetic eld cannot be sustained against Ohmic dissipation. In at space, this result is known as Cowling's anti-dynamo theorem. No support is found for the possibility that a gravitomagnetic dynamo eeect could le...

The interplay between disorder, quantum fluctuations, and dissipation is studied in the random transverse Ising chain coupled to a dissipative Ohmic bath with a real space renormalization group. A typically very large length scale L* is identified above which the physics of frozen clusters dominates. Below L* a strong-disorder fixed point determines scaling at a pseudocritical point. In a Griff...

We have fabricated two-dimensional (2D) small-Josephson-junction arrays of which each Al-AlOx-Al junction is shunted by a Cr resistor. The arrays with large junction resistance and large charging energy show a transition from insulating to superconducting behavior when the shunt resistance is lowered below a critical value, which is close to 2R(Q) ( R(Q) identical withh/4e(2) = 6.45 kOmega). Th...

Transport as well as magnetic relaxation properties of the mixed state were studied on strongly underdoped Y12xPrxBa2Cu3O72d crystals. We observed two correlated phenomena—a coupling transition and a transition to quantum creep. The distribution of transport current below the coupling transition is highly nonuniform, which facilitates quantum creep. We speculate that in the mixed state below th...

Abstract We perform a linear analysis of the stability isothermal, rotating, magnetic, self-gravitating sheets that are weakly ionized. The magnetic field and rotation axis perpendicular to sheet. include self-consistent treatment thermal pressure, gravitational, rotational, (pressure tension) forces together with two nonideal magnetohydrodynamic (MHD) effects (ohmic dissipation ambipolar diffu...

Abstract Spin precession in magnetic materials is commonly modelled with the classical phenomenological Landau–Lifshitz–Gilbert (LLG) equation. Based on a quantized three-dimensional spin + environment Hamiltonian, we here derive operator equation of motion that describes and includes general form damping consistently accounts for memory, coloured noise quantum statistics. The LLG recovered as ...