144 research outputs found
Superconducting Qubits Coupled to Nanoelectromechanical Resonators: An Architecture for Solid-State Quantum Information Processing
We describe the design for a scalable, solid-state
quantum-information-processing architecture based on the integration of
GHz-frequency nanomechanical resonators with Josephson tunnel junctions, which
has the potential for demonstrating a variety of single- and multi-qubit
operations critical to quantum computation. The computational qubits are
eigenstates of large-area, current-biased Josephson junctions, manipulated and
measured using strobed external circuitry. Two or more of these phase qubits
are capacitively coupled to a high-quality-factor piezoelectric
nanoelectromechanical disk resonator, which forms the backbone of our
architecture, and which enables coherent coupling of the qubits. The integrated
system is analogous to one or more few-level atoms (the Josephson junction
qubits) in an electromagnetic cavity (the nanomechanical resonator). However,
unlike existing approaches using atoms in electromagnetic cavities, here we can
individually tune the level spacing of the ``atoms'' and control their
``electromagnetic'' interaction strength. We show theoretically that quantum
states prepared in a Josephson junction can be passed to the nanomechanical
resonator and stored there, and then can be passed back to the original
junction or transferred to another with high fidelity. The resonator can also
be used to produce maximally entangled Bell states between a pair of Josephson
junctions. Many such junction-resonator complexes can assembled in a
hub-and-spoke layout, resulting in a large-scale quantum circuit. Our proposed
architecture combines desirable features of both solid-state and cavity quantum
electrodynamics approaches, and could make quantum information processing
possible in a scalable, solid-state environment.Comment: 20 pages, 14 separate low-resolution jpeg figure
Nanomechanical Quantum Memory for Superconducting Qubits
Many protocols for quantum computation require a quantum memory element to
store qubits. We discuss the accuracy with which quantum states prepared in a
Josephson junction qubit can be stored in a nanoelectromechanical resonator and
then transfered back to the junction. We find that the fidelity of the memory
operation depends on both the junction-resonator coupling strength and the
location of the state on the Bloch sphere. Although we specifically focus on a
large-area, current-biased Josesphson junction phase qubit coupled to the
dilatational mode of a piezoelectric nanoelectromechanical disk resonator, many
our results will apply to other qubit-oscillator models.Comment: 4 pages, Revte
Mechanical Computation, Redux?
Nanoscale mechanical devices offer the prospect of signal
processing, computation, and sensing – at microwave
frequencies, sub-nanosecond time scales, and with
unprecedented sensitivity and consumption of extremely small
amounts of power. In this brief paper I will review the current state-of-the art of nanoelectromechanical systems (NEMS) – with respect to both the underlying fundamental science, and realized (or realizable) applications. The paper concludes with my speculations regarding the future role of nanomechanics in computation, in the context of the rich and rather surprising history of (macroscale) mechanically-based logic
High-speed multiple-mode mass-sensing resolves dynamic nanoscale mass distributions
Simultaneously measuring multiple eigenmode frequencies of nanomechanical resonators can determine the position and mass of surface-adsorbed proteins, and could ultimately reveal the mass tomography of nanoscale analytes. However, existing measurement techniques are slow (<1 Hz bandwidth), limiting throughput and preventing use with resonators generating fast transient signals. Here we develop a general platform for independently and simultaneously oscillating multiple modes of mechanical resonators, enabling frequency measurements that can precisely track fast transient signals within a user-defined bandwidth that exceeds 500 Hz. We use this enhanced bandwidth to resolve signals from multiple nanoparticles flowing simultaneously through a suspended nanochannel resonator and show that four resonant modes are sufficient for determining their individual position and mass with an accuracy near 150 nm and 40 attograms throughout their 150-ms transit. We envision that our method can be readily extended to other systems to increase bandwidth, number of modes, or number of resonators.United States. Army Research Office (Grant W911NF-09-0001)Center for Integration of Medicine and Innovative Technology (Contract 09-440)National Science Foundation (U.S.) (Grant 1129359
Co-integration of Silicon Nanodevices and NEMS for Advanced Information Processing (Invited Talk)
In this paper we present our recent attempts at developing the advanced information processing devices by integrating nano-electro-mechanical (NEM)structures into conventional silicon nanodevices. Firstly, we show high-speed and nonvolatile NEM memory which features a mechanically-bistable floating gate is integrated onto MOSFETs. Secondly we discuss hybrid systems of single-electron transistors and NEM structures for exploring new switching principles
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
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