By Scott Sullivan
Editor
Dead in the Water
Our Physics Made Simple series has been on hold due to popular demand. Not that physics is so complex it’s incomprehensible, just my writing. Are physicists geniuses or the rest of us so dumb we think they are? Time for another chapter.
Water can be dead, electrically speaking. So say physicists claiming studies show H2O a few molecules thick near solid surfaces doesn’t respond to electric fields.
This has huge implications on life, they claim. Without grants to pursue future arcane studies, Ph.D.’s may have to resort to a diet of Beanie Weenies.
How water interacts with electricity, says Dr. Andre Geim of the Natural Graphene Institute, plays an important role in shaping biological molecules such as proteins.
(Graphene, the strongest material ever tested, is the basic structural element of carbon allotropes such as graphite, diamond, carbon nanotubes and fullerenes. Of course, such an Institute studies water.)
“One can probably claim that interfacial water shapes life as we know it, both literally and figuratively,” Geim says.
“Water covers every surface around us,” adds Dr. Laura Fumagalli, also of the Institute. “We don’t see it but it’s there.
“Until now, this surface water was presumed to behave differently from the normal water famous for its anomalously high dielectric constant.” Who knew that constant is world renowned?
“It was a surprise,” Fumagalli continues, “to find that the dielectric constant of interfacial water was anomalous too. However its polarizability is anomalously low rather than anomalously high.”
Having assumed that the polarizability of interfacial water was anomalously low, like everyone, I was floored. This turns my world upside down. I will never look at a carbon nanotube or fullerene quite the same.
The more I learn the more I regret it. In other physics news, spectral cloaking can make things invisible. How? A new study shows manipulating the frequency, or color, of light waves as they pass through objects can overcome shortcomings of existing cloaking technologies.
Most current cloaking devices, says phys.org, can fully conceal objects only when they’re illuminated with one color. Sunlight and most other sources of light are broadband, i.e. contain many colors.
The new spectral invisibility cloak can completely hide objects under broadband illumination — so it dis-appears. In theory, it could be extended to make 3-D objects invisible from all directions.
Who hasn’t wanted to be invisible? Or at least be that way selectively? No politician who calls for transparency, that’s for sure.
All you need is two pairs of temporal phase modulators and dispersive optical fibers, both available commercially. Pick them up at, say, Dollar General, set up pairs on both sides of an optical filter (oops, you need those too) and, presto: the laser pulse will look like it propagated through a non-absorbing medium.
With any luck Ronco will soon be selling these. Just because the company went bankrupt 11 years ago doesn’t mean it can’t make a comeback by packaging S.I. Cloaks with Veg-O-Matics and Pocket Fishermen. We can slice, dice, catch fish and be invisible all at once.
Wait, there’s more. Two physicists have succeeded in generating ultra-short electric pulses on a chip using metal antennas just a few nanometers thick, then running the signals a few millimeters above the surface and reading them again in a controlled manner.
This enables the development of new, powerful terahertz components. Think giga- hurts? Wait till you meet tera-. Using tiny plasmonic antennae and running them over a chip, the two excited the antennae to emit more electrons on their pointed side than on opposite flat ones.
“In photoemission, the light pulse causes electrons to be emitted from metal into the vacuums,” explains Christoph Karnetzky. Why didn’t you or I think of that?
“Come excite my electrons,” I’d invite the she-physicist cloaked demurely inside a lab coat.
“Your ultra-short pulses do nothing for me,” she’d reply, whacking me with the nearest graphene.
So the light pulses, like our ardor, only last a few femtoseconds (one quadrillionth, or .000000000000001 of a second). That’s long enough to reap benefits of this finding.
Science marches on.
