2,526 research outputs found
Controllable Goos-H\"{a}nchen shifts and spin beam splitter for ballistic electrons in a parabolic quantum well under a uniform magnetic field
The quantum Goos-H\"{a}nchen shift for ballistic electrons is investigated in
a parabolic potential well under a uniform vertical magnetic field. It is found
that the Goos-H\"{a}nchen shift can be negative as well as positive, and
becomes zero at transmission resonances. The beam shift depends not only on the
incident energy and incidence angle, but also on the magnetic field and Landau
quantum number. Based on these phenomena, we propose an alternative way to
realize the spin beam splitter in the proposed spintronic device, which can
completely separate spin-up and spin-down electron beams by negative and
positive Goos-H\"{a}nchen shifts.Comment: 6 pages, 6 figure
An efficient non-linear Feshbach engine
We investigate a thermodynamic cycle using a Bose-Einstein condensate with
nonlinear interactions as the working medium. Exploiting Feshbach resonances to
change the interaction strength of the BEC allows us to produce work by
expanding and compressing the gas. To ensure a large power output from this
engine these strokes must be performed on a short timescale, however such
non-adiabatic strokes can create irreversible work which degrades the engine's
efficiency. To combat this, we design a shortcut to adiabaticity which can
achieve an adiabatic-like evolution within a finite time, therefore
significantly reducing the out-of-equilibrium excitations in the BEC. We
investigate the effect of the shortcut to adiabaticity on the efficiency and
power output of the engine and show that the tunable nonlinearity strength,
modulated by Feshbach resonances, serves as a useful tool to enhance the
system's performance.Comment: 8 pages, 5 figures. To Appear New J. Phys. Focus on Shortcuts to
Adiabaticit
- …