Two problems incorporating a set of horizontal linear potentials crossed by a sloped linear potential are solved analytically and compared with numerical results: (a) the case where boundary conditions are specified at the ends of a finite interval and (b) the case where the sloped linear potential is replaced by a piecewise-linear sloped potential and the boundary conditions are specified at i...

Resistivity measurements were performed on Pr1−xLaxOs4Sb12 single crystals at temperatures down to 20 mK and in fields up to 18 T. The results for dilute-Pr samples x=0.3 and 0.67 are consistent with model calculations performed assuming a singlet crystalline-electric-field CEF ground state. The residual resistivity of these crystals features a smeared step centered around 9 T, the predicted cr...

Theories unifying gravity and other interactions suggest the possibility of spatial and temporal variation of physical “constants” in the Universe. Detection of high redshift absorption systems intersecting the sight lines towards distant quasars provide a powerful tool for measuring these variations. In the present paper we demonstrate that high sensitivity to variation of the fine structure c...

K. Alberi,1,2 J. Wu,1,2 W. Walukiewicz,1 K. M. Yu,1 O. D. Dubon,1,2 S. P. Watkins,3 C. X. Wang,3 X. Liu,4 Y.-J. Cho,4 and J. Furdyna4 1Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA 2Department of Materials Science and Engineering, University of California, Berkeley, California 94720, USA 3Department of Physics, Simon Fraser University, Burna...

The most primitive form of a stadium is a circle, say of radius r. If we separate the left and right halves of the circle slightly and connect these two semi circles at the top and bottom by straight lines we have a classical stadium (racetrack). Let a be the horizontal distance from the center of the figure to either the left or right semi circle; that is, the distance of each ‘straightaway’ i...

We exploit the concept of Landau-Zener transitions at avoided energy crossings as a quantum-control tool. In an avoided crossing the two quantum states interchange their characteristics as an external parameter is varied. Depending on the rate of change of the parameter it is possible to control the final state. We use this simple idea to travel along the energy spectrum of a realistic system: ...

We study the dynamics of a molecule’s nuclear wave-function near an avoided crossing of two electronic energy levels, for one nuclear degree of freedom. We derive the general form of the Schrödinger equation in the n-th superadiabatic representation for all n ∈ N, and give some partial results about the asymptotics for large n. Using these results, we obtain closed formulas for the time develop...

We present results from simulations of vibrational energy and phase relaxation and electronic curve crossing using a multilevel formulation of Redfield theory, which demonstrate the shortcomings of the optical Bloch approximation and the importance of coherence transfer processes in the relaxation dynamics of multilevel systems. Specifically, we show that for a harmonic well, energy relaxation ...

We compare the observed splitting in the PL spectrum of a strongly coupled light-matter system, with the splitting of its dressed modes. In the presence of non-negligible decoherence, the two may differ considerably. Whereas the dressed mode splitting has a simple expression, the observed splitting has no general analytical expression in terms of radicals of the system parameters.

Bragg band gaps of phononic crystals generally, but not always, open at Brillouin zone boundaries. The commonly accepted explanation stems from the empty lattice model: assuming a small material contrast between the constituents of the unit cell, avoided crossings in the phononic band structure appear at frequencies and wavenumbers corresponding to band intersections; for scalar waves the lowes...