9,473 research outputs found
Fast ground-state cooling of mechanical resonator with time-dependent optical cavities
We propose a feasible scheme to cool down a mechanical resonator (MR) in a
three-mirror cavity optomechanical system with controllable external optical
drives. Under the Born-Oppenheimer (BO) approximation, the whole dynamics of
the mechanical resonator and cavities is reduced to that of a time-dependent
harmonic oscillator, whose effective frequency can be controlled through the
optical driving fields. The fast cooling of the MR can be realized by
controlling the amplitude of the optical drives. Significantly, we further show
that the ground-state cooling may be achieved via the three-mirror cavity
optomechanical system without the resolved sideband condition.Comment: Some references including our previous works on cooling of mechanical
resonators are added, and some typos are corrected in this new version.
Comments are welcom
Fluctuation-induced tunneling conduction through RuO nanowire contacts
A good understanding of the electronic conduction processes through
nanocontacts is a crucial step for the implementation of functional
nanoelectronic devices. We have studied the current-voltage (-)
characteristics of nanocontacts between single metallic RuO nanowires (NWs)
and contacting Au electrodes which were pre-patterned by simple
photolithography. Both the temperature behavior of contact resistance in the
low-bias voltage ohmic regime and the - curves in the high-bias voltage
non-ohmic regime have been investigated. We found that the electronic
conduction processes in the wide temperature interval 1--300 K can be well
described by the fluctuation-induced tunneling (FIT) conduction theory. Taken
together with our previous work (Lin {\it et al.}, Nanotechnology {\bf 19},
365201 (2008)) where the nanocontacts were fabricated by delicate electron-beam
lithography, our study demonstrates the general validity of the FIT model in
characterizing electronic nanocontacts.Comment: 6 pages, 5 figure
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