Nanomechanical Computing

Logically reversible and irreversible computation

Motivated by the challenge of energy-efficient computing with existing transistor-based technologies, we are focusing on an alternate architecture that uses nanomechanical resonators as building blocks of reversible and irreversible logic gates. We have recently demonstrated low-power computation with logically-reversible nanomechanical Fredkin gate and a logically-irreversible reprogrammable NAND/NOR gate.

To circumvent the limitations of irreversible computations, an important objective is the development of reversible logic gates, as proposed by Fredkin, Toffoli, Wilczek, Feynman and others. Reversible computing includes any reversible logic gate that has a bijective mapping between its input and output. In other words, these devices must have the same number of inputs and outputs and must recover initial inputs when the outputs of a computation are fed back into the device. The primary motivation for reversible computing is that it provides the only way that performance for given power constraints can increase indefinitely. Our novel approach is to utilize a mechanical logic architecture for implementing the Fredkin gate, a universal logic gate from which any reversible computation can be built. This approach enables us to address a key question on the existence of fundamental limit to energy cost in computing. We have been building universal logic gates, capable of processing information with an energy cost approaching the fundamental von Neuman-Landauer limit, kBTln2 per operation.

Featured

Coherent signal amplification in bistable nanomechanical oscillators by stochastic resonance.

Stochastic resonance is a counterintuitive concept: the addition of noise to a noisy system induces coherent amplification of its response.

A Nanomechanical Fredkin Gate

Irreversible logic operations inevitably discard information, setting fundamental limitations on the flexibility and the efficiency of modern computation. To circumvent the limit imposed by the von Neumann–Landauer (VNL) principle, an important objective is the development of reversible logic gates, as proposed by Fredkin, Toffoli, Wilczek, Feynman, and others.

A Noise-Assisted Reprogrammable Nanomechanical Logic Gate

We present a nanomechanical device, operating as a reprogrammable logic gate, and performing fundamental logic functions such as AND/OR and NAND/NOR. The logic function can be programmed (e.g., from AND to OR) dynamically, by adjusting the resonator’s operating parameters.

A Controllable Nanomechanical Memory Element.

We report the realization of a completely controllable high-speed nanomechanical memory element fabricated from single-crystal silicon wafers.

Electrostatically actuated silicon-based nanomechanical switch at room temperature.

We demonstrate a silicon-based high-frequency nanomechanical device capable of switching controllably between two states at room temperature.

Temperature Dependence of a Nanomechanical Memory Switch

We present the effect of temperature on the switching characteristics of a bistable nonlinear nanomechanical beam.