258 research outputs found
Putting mechanics into quantum mechanics
Nanoelectromechanical structures are starting to approach the ultimate quantum mechanical limits for detecting and exciting motion at the nanoscale. Nonclassical states of a mechanical resonator are also on the horizon
Non-adiabatic dynamics of two strongly coupled nanomechanical resonator modes
The Landau-Zener transition is a fundamental concept for dynamical quantum
systems and has been studied in numerous fields of physics. Here we present a
classical mechanical model system exhibiting analogous behaviour using two
inversely tuneable, strongly coupled modes of the same nanomechanical beam
resonator. In the adiabatic limit, the anticrossing between the two modes is
observed and the coupling strength extracted. Sweeping an initialized mode
across the coupling region allows mapping of the progression from diabatic to
adiabatic transitions as a function of the sweep rate
Hybrid quantum device based on NV centers in diamond nanomechanical resonators plus superconducting waveguide cavities
We propose and analyze a hybrid device by integrating a microscale diamond
beam with a single built-in nitrogen-vacancy (NV) center spin to a
superconducting coplanar waveguide (CPW) cavity. We find that under an ac
electric field the quantized motion of the diamond beam can strongly couple to
the single cavity photons via dielectric interaction. Together with the strong
spin-motion interaction via a large magnetic field gradient, it provides a
hybrid quantum device where the dia- mond resonator can strongly couple both to
the single microwave cavity photons and to the single NV center spin. This
enables coherent information transfer and effective coupling between the NV
spin and the CPW cavity via mechanically dark polaritons. This hybrid
spin-electromechanical de- vice, with tunable couplings by external fields,
offers a realistic platform for implementing quantum information with single NV
spins, diamond mechanical resonators, and single microwave photons.Comment: Accepted by Phys. Rev. Applie
Quantum dot opto-mechanics in a fully self-assembled nanowire
We show that fully self-assembled optically-active quantum dots (QDs)
embedded in MBE-grown GaAs/AlGaAs core-shell nanowires (NWs) are coupled to the
NW mechanical motion. Oscillations of the NW modulate the QD emission energy in
a broad range exceeding 14 meV. Furthermore, this opto-mechanical interaction
enables the dynamical tuning of two neighboring QDs into resonance, possibly
allowing for emitter-emitter coupling. Both the QDs and the coupling mechanism
-- material strain -- are intrinsic to the NW structure and do not depend on
any functionalization or external field. Such systems open up the prospect of
using QDs to probe and control the mechanical state of a NW, or conversely of
making a quantum non-demolition readout of a QD state through a position
measurement.Comment: 20 pages, 6 figure
Nanomechanical Resonators: Toward Atomic Scale
The quest for realizing and manipulating ever smaller man-made movable structures and dynamical machines has spurred tremendous endeavors, led to important discoveries, and inspired researchers to venture to new grounds. Scientific feats and technological milestones of miniaturization of mechanical structures have been widely accomplished by advances in machining and sculpturing ever shrinking features out of bulk materials such as silicon. With the flourishing multidisciplinary field of low-dimensional nanomaterials, including one-dimensional (1D) nanowires/nanotubes, and two-dimensional (2D) atomic layers such as graphene/phosphorene, growing interests and sustained efforts have been devoted to creating mechanical devices toward the ultimate limit of miniaturization— genuinely down to the molecular or even atomic scale. These ultrasmall movable structures, particularly nanomechanical resonators that exploit the vibratory motion in these 1D and 2D nano-to-atomic-scale structures, offer exceptional device-level attributes, such as ultralow mass, ultrawide frequency tuning range, broad dynamic range, and ultralow power consumption, thus holding strong promises for both fundamental studies and engineering applications. In this Review, we offer a comprehensive overview and summary of this vibrant field, present the state-of-the-art devices and evaluate their specifications and performance, outline important achievements, and postulate future directions for studying these miniscule yet intriguing molecular-scale machines
Electronic spin working mechanically
A single-electron tunneling (SET) device with a nanoscale central island that
can move with respect to the bulk source- and drain electrodes allows for a
nanoelectromechanical (NEM) coupling between the electrical current through the
device and mechanical vibrations of the island. Although an electromechanical
"shuttle" instability and the associated phenomenon of single-electron
shuttling were predicted more than 15 years ago, both theoretical and
experimental studies of NEM-SET structures are still carried out. New
functionalities based on quantum coherence, Coulomb correlations and coherent
electron-spin dynamics are of particular current interest. In this article we
present a short review of recent activities in this area.Comment: 17 pages, 11 figures. arXiv admin note: substantial text overlap with
arXiv:1303.074
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