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In this chapter, we explore the underlying dynamics of a coupled bistable system realized by coupling microelectronic circuits which belong to the same class of dynamics as the ferromagnetic system studied in the previous chapter.

The mechanical influence on objects due to their interaction with light has been a central topic in atomic physics for decades. Thus, not surprisingly, one finds that many concepts developed to describe cavity optomechanical systems with solid-state mechanical oscillators have also been developed in a parallel stream of scientific literature pertaining to cold atomic physics. In this chapter, I describe several of these ideas from atomic physics, including optical methods for detecting quantum states of single cold atoms and atomic ensembles, motional effects within single-atom cavity quantum electrodynamics, and collective optical effects such as superradiant Rayleigh scattering and cavity cooling of atomic ensembles. Against this background, I present several experimental realizations of cavity optomechanics in which an atomic ensemble serves as the mechanical element. These are divided between systems driven either by sending light onto the cavity input mirrors (“cavity pumped”), or by sending light onto the atomic ensemble (“side pumped”). The cavity-pumped systems clearly exhibit the key phenomena of cavity optomechanical systems, including cavity-aided position sensing, coherent back action effects such as the optical spring and cavity cooling, and optomechanical bistability; several of these effects have been detected not only for linear but also for quadratic optomechanical coupling. The extreme isolation of the atomic ensemble from mechanical disturbances, and its strong polarizability near the atomic resonance frequency, allow these optomechanical systems to be highly sensitive to quantum radiation pressure fluctuations. I describe several ways in which these fluctuations are observed experimentally. I conclude by considering the side-pumped cavity experiments in terms of cavity optomechanics, complementing recent treatments of these systems in terms of condensed-matter physics concepts such as quantum phase transitions and supersolidity.

Quantum-dot cellular automata (QCA) is a paradigm for connecting nanoscale bistable devices to accomplish general-purpose computation. The idea has its origins in the technology of quantum dots, Coulomb blockade, and Landauer’s observations on digital devices and energy dissipation. We examine the early development of this paradigm and its various implementations.

This paper presents novel ultra-light booms for solar sails and other large deployable space structures. These CFRP booms have a unique property: bistability over the whole length (BOWL), which enables simple and compact deployment mechanism designs that can reduce overall system mass. They were produced to solve some of the previously encountered problems with bistable composite tubular booms that reduced their optimal length and scalability due to local buckling phenomena when the diameter of the coil increased. A new low-cost manufacturing technique, which consists of using braids with a variable angle change over the boom length, was found to have a positive effect in reducing that tendency. An analytical model is used to explain this behavior and predict the secondary stable state properties and natural diameter of the coiled/packed boom. A 3.6 m tape spring version of these bistable CFRP booms has been designed for a 25 m2 Gossamer Sail Deorbiter of future space assets and is being considered for an upcoming solar sail demonstration mission called CubeSail. Larger booms are being designed for a new scalable roll-up solar array concept.

Trabajo presentado al 22nd PATMOS celebrado en Newcastle del 4 al 6 de septirmbre de 2012., Monostable to Bistable (MOBILE) gates are very suitable for the implementation of gate-level pipelines which can be achieved without resorting to memory elements. MOBILE operating principle is implemented using two series connected Negative Differential Resistance (NDR) devices with a clocked bias. This paper describes and experimentally validates a two-phase clock scheme for such MOBILE based ultra-grain pipelines. Up to our knowledge it is the first MOBILE working circuit reported with this interconnection architecture. The proposed interconnection architecture is applied to the design of a 4-bit Carry Look-ahead Adder., This work has been funded by Ministerio de Economía y Competitividad del Gobierno de España with support from ERDF under Project TEC2010-18937.

This chapter aims at giving an overview of the different types of fullerene-stoppered bistable rotaxanes, their switching mechanism and their potential applications with a special focus on fullerene-driven molecular shuttles.