System Bits: Jan. 28

Collaborative software for linking performance, cost
Researchers from Georgia Tech have created a web-based tool that lets physically-separated participants collaborate on model-based systems engineering projects.

Referred to as the Framework for Assessing Cost and Technology (FACT), the program utilizes open-source software components to allow users to visualize a system’s potential expense alongside its performance, reliability and other factors, they said. With the tool, users can pull all aspects of a project together into a single modeling and simulation process.

Specifically, the tool gives users the capacity to weigh cost along with performance factors; adapt the tool to a wide range of systems engineering problems; track the entire collaborative process; implement advanced security and configurability features; collaborate among any systems engineering platforms with web access.

Modeling and simulation software for military applications has traditionally been used to address performance issues such as investigate the capabilities of air or ground vehicles, or radar systems’ effectiveness against hostile action, and do an excellent job of answering the ‘how fast, how well’ questions. However, these are rarely seen working in either collaborative or cost-aware environments, the researchers explained.

Using the FACT tool, users can do trade-space analysis, which allows them to juggle performance, cost and other factors, such as examining vehicle convoy logistics to investigate the complex interrelationship of vehicles, personnel, supplies and cost to pinpoint optimal combinations.

While the FACT tool itself will likely be limited to military use, software frameworks similar to FACT could be used in both academic and commercial systems engineering needs.

Mathematically exact
How would electrons behave if confined to a wire so slender they could pass through it only in single-file? The question has intrigued scientists for more than half a century. In 1950, Japanese Nobel Prize winner Sin-Itiro Tomonaga, followed by American physicist Joaquin Mazdak Luttinger in 1963, came up with a mathematical model showing that the effects of one particle on all others in a one-dimensional line would be much greater than in two- or three-dimensional spaces. Among quantum physicists, this model came to be known as the “Luttinger liquid” state.

But until very recently, there had been only a few successful attempts to test the model in devices similar to those in computers, because of the engineering complexity involved. Now, scientists from McGill University and Sandia National Laboratories have succeeded in conducting a new experiment that supports the existence of the long-sought-after Luttinger liquid state. Their findings validate important predictions of the Luttinger liquid model.

The new study follows on the team’s discovery in 2011 of a way to engineer one of the world’s smallest electronic circuits, formed by two wires separated by only about 15 nanometers.

One-dimensional quantum physics involves all of the electrons becoming coupled to one another and the solutions being mathematically exact, compared to most other cases where thesolutions are only approximate.

Using an electric circuit formed by two wires separated by only about 15 nanometers, the researchers measured the effect that a very small electrical current in one of the wires has on the other. This can be viewed as the “friction” or “drag” between the two circuits, and the experiment shows that this effect increases as the circuits are cooled to extremely low temperatures – consistent with a strong prediction of Luttinger liquid theory. (Source: McGill University)

The researchers believe the findings could lead to practical applications in electronics and other fields. While it’s difficult at this stage to predict what those might be, the same was true in the case of the laser when it was invented. Nanotechnologies are already helping in medicine, electronics and engineering – and this work shows that they can help get to the bottom of a long-standing question in quantum physics.