Applied Physics

Revelations of the extent of American government surveillance into the private lives of both the American public and foreign leaders worldwide has shone a spotlight on the lack of security in digital communications.

Even today's encrypted data is vulnerable but physics may come to the rescue, according to a Nature article by Artur Ekert and Renato Renner ("The ultimate physical limits of privacy", doi:10.1038/nature13132).


Our bones are a matrix of minerals and other substances, including living cells, though most people don't think of them that way and assume bones are 'natural' —  but nature can be coaxed to do all kinds of things.

MIT engineers have coaxed bacterial cells to produce biofilms that can incorporate nonliving materials, such as gold nanoparticles and quantum dots. These "living materials" combine the advantages of live cells, which respond to their environment, produce complex biological molecules, and span multiple length scales, with the benefits of nonliving materials, but they add functions we don't usually associate with biology.

Self-assembling materials


Collectors,museums and art dealers face a lot of problems determining origin, authenticity and discovery of forgery of artwork. Experts are easily fooled - but science, not so much.

They get help through the application of modern, non-destructive, "hi-tech" techniques.  Spectroscopy is a technique that has been useful in the fight against art fraud because it can determine chemical composition of pigments and binders, which is essential information in the hands of an art specialist in revealing fakes. As described in a recent paper, "…according to the FBI, the value of art fraud, forgery and theft is up to $6 billion per year, which makes it the third most lucrative crime in the world after drug trafficking and the illegal weapons trade." 


There’s a popular YouTube video featuring mathematician Edward Frenkel where he describes how the NSA hacked our emails. It is a backdoor into the National Institute of Standards and Technology public key encryption standards.

I’ll borrow an analogy for a simplified description of how public key encryption works from Simon Singh. Imagine a sturdy metal box that can be locked shut with a padlock.

By now, almost everyone understands computers and that current technologies for writing, storing, and reading information are either charge-based or spin-based.

Spin-based devices operate on the principle that in materials like iron, electron spins generate magnetism and the position of the north and south pole of the magnet can be used to store the zeros and ones. This technology is behind both magnetic stripe cards and terabyte computer hard disks. Since these devices are based on spin, they are more robust against charge perturbations but the drawback is that in order to reverse the north and south poles of the magnet, i.e., flip the zero to one or vice versa, the magnetic bit has to be coupled to an electro-magnet or to another permanent magnet.


In my previous article DC Versus AC I discussed how a diode can be used as a rectifier to convert alternating current (AC) into direct current (DC) because the diode allows current to flow in one direction, but not the other.

The diode is the simplest semiconductor electronic component, but the physics of how they work is perhaps somewhat complicated. There are many resources available on the web such as the Edison Tech Center semiconductor resource page.

New battery management technology could boost Li-ion capacity by 40%, quadruple recharging cycles

Long-life laptop battery the tech industry doesn’t want you to have ?

Fed up with the dwindling battery life of his BlackBerry Bold 9000, Carleton University chemistry student Tim Sherstyuk took a straightforward problem to his electrical engineer dad, Nick: Could the two of them come up with the technology to make a standard lithium-ion battery last longer?
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Researchers have used fishing line fiber and sewing thread to create inexpensive artificial muscles.
 
The inexpensive, artificial muscles generate far more force and power than human or animal muscles of the same size and could be used in medical devices, humanoid robots, prosthetic limbs, or woven into fabrics.

"In terms of the strength and power of the artificial muscle, we found that it can quickly lift weights 100 times heavier than a same-sized human muscle can, in a single contraction," says University of British Columbia Electrical and Computer Engineering professor John Madden. "It also has a higher power output for its weight than that of an automobile combustion engine."


Goodbye Ohm - Hello Heisenberg

Research reported earlier this month shows that electrical resistance in nanoribbons of epitaxial graphene changes in discrete steps following quantum mechanical principles.


In plain language, electron transport in a new variant of graphene doesn't obey Ohm's law: the resistance of the material is independent of current.  However, unlike the case with a normal conductor where you can stick a multimeter across any two points on a wire and measure the voltage, if you probe this new material you increase the resistance.  Shades of Heisenberg.

The discovery of what is essentially a 3D version of graphene – the 2D sheets of carbon through which electrons race at many times the speed at which they move through silicon - could lead to much faster transistors and far more compact hard drives.

Researchers at Lawrence Berkeley National Laboratory have discovered that sodium bismuthate can exist as a form of quantum matter called a three-dimensional topological Dirac semi-metal (3DTDS).

This is the first experimental confirmation of 3D Dirac fermions in the interior or bulk of a material, a novel state that was only recently proposed by theorists.