Programmable matter

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Programmable matter is a term originally coined in 1991 by Toffoli and Margolus to refer to an ensemble of fine-grained computing elements arranged in space (Toffoli & Margolus 1991). In this context, programmable matter refers to compute models similar to cellular automata and lattice gas automata (Rothman & Zaleski 1997). The CAM-8 architecture is an example hardware realization of this model. The main application of programmable matter, as envisioned by this community, is to use the spatial nature of the computing medium to simulate physical systems.

As semiconductor technology and nanotechnology have advanced the use of the term programmable matter has changed to reflect the fact that it is possible to build an ensemble of elements which can be "programmed" to change their physical properties in reality not just in simulation. Thus, programmable matter has come to mean "any bulk substance which can be programmed to change its physical properties." In one school of thought the programming could be external to the material and might be achieved by the "application of light, voltage, electric or magnetic fields, etc." (McCarthy 2006). For example, in this school of thought an LCD display is a form of programmable matter. A second school of thought is that the individual units of the ensemble can compute and the result of their computation is a change in the ensembles physical properties. An example of this more ambitious form of programmable matter is claytronics, where the units in the ensemble "compute" and the result is a change in the shape of the ensemble. .

There are many proposed instantiations of programmable matter. Scale is one key differentiator between different forms of programmable matter. At one end of the spectrum reconfigurable modular robotics pursues a form of programmable matter where the individual units are in the centimeter size range (e.g., [1][2][3]). At the nanoscale end of the spectrum there are a tremendous number of different basis for programmable matter, ranging from shape changing molecules (e.g., [4]) to quantum dots. Quantum dots are in fact often referred to as artificial atoms. In the micrometre to sub-millimeter range examples include: claytronics, currently working on MEMS-based units, cells created using synthetic biology, and the utility fog concept.

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[edit] History

In 1991, Toffoli and Margolus the first paper to describe a programmable matter system (Toffoli & Margolus 1991). Their paper describes a computing substrate that is composed of fine-grained compute nodes distributed throughout space which communicate using only nearest neighbor interactions.

In the early 1990s there was a significant amount of work in reconfigurable modular robotics with a philosophy similar to programmable matter.

In the summer of 1998, In a discussion on artificial atoms and programmable matter, Wil McCarthy and G. Snyder coined the term "quantum wellstone" (or simply "wellstone") to describe this hypothetical but plausible form of programmable matter. Wil McCarthy has used the term in his fiction.

In 2002, Seth Goldstein and Todd Mowry started the claytronics project at Carnegie Mellon University to investigate the underlying hardware and software mechanisms necessary to realize programmable matter.

[edit] Examples of Programmable matter

Below are some specific examples of programmable matter.

[edit] Complex fluids

The physical properties of several complex fluids can be modified by applying a current or voltage, as is the case with liquid crystals.

[edit] Quantum wells

Quantum wells can hold one or more electrons. Those electrons behave like an artificial atom, which like real atoms can form covalent bonds. Because of their larger sizes, other properties are widely different.

[edit] Metamaterials

Main article: Metamaterial

Metamaterials are artificial composites that can be controlled to react in ways that do not occur in nature. One example developed by David Smith and then by John Pendry and David Schuri is of a material that can have its index of refraction tuned so that it can have a different index of refraction at different points in the material. If tuned properly this could result in an "invisibility cloak."

[edit] Cellular Automata

Main article: Cellular Automata

[edit] Shape Changing Molecules

An active area of research is in molecules that can change their shape, as well as other properties, in response to external stimuli. These molecules can be used individually or en masse to form new kinds of materials. For example, J Fraser Stoddart's group at UCLA has been developing molecules that can change their electrical properties.

[edit] Claytronics

Main article: Claytronics

[edit] Reconfigurable Modular Robotics

Self-Reconfiguring Modular Robotics is a field of robotics in which a group of usually identical robots work together to dynamically form shapes suitable for each task. See (Yim et al. 2007, pp. 43-52) for an overview of recent work and challenges.

[edit] Synthetic Biology

Synthetic biology is a field that aims to engineer cells with "novel biological functions." Such cells are usually used to create larger systems (e.g., biofilms) which can be "programmed" utilizing synthetic gene networks such as genetic toggle switches, to change their color, shape, etc.

[edit] Programmable Matter in fiction

Programmable matter is still, for the most part, a fantastic vision for the future. The ideas behind it are explored in many works of science fiction. For example (This list is very incomplete):

  • It is called "Trillions" in the children's book "Trillions", by Nicholas Fisk (1973), ISBN-10: 0394926013
  • It is called "reality graphics" in Vinge, Vernor (1992). A Fire Upon the Deep. 
  • It is called "wellstone" in McCarthy, Wil (1999). Once Upon a Matter Crushed. 
  • Brin, David (2002). Kiln people. 
  • It is called "Computronium" in Stross, Charles (2005). Accelerando. 
  • Programmable Silicon is used to quickly erect buildings in Peter F Hamilton's Night's Dawn Trilogy

[edit] See also

[edit] References

  • McCarthy, Wil (2003), Hacking Matter: Levitating Chairs, Quantum Mirages, and the Infinite Weirdness of Programmable Atoms, ISBN 0-465-04428-X 


[edit] External links