What you see above is a rough diagram of how to achieve invisibility, and it’s basically saying one thing: invisibility cloaks are still a far way off.  If we need an 18,600 mile-long machine for just a second of invisibility, how big is the machine that lets me sneak into your house and watch you sleep?

“This approach is based on accelerating the front part of a probe light beam and slowing down its rear part to create a well controlled temporal gap – inside which an event occurs – such that the probe beam is not modified in any way by the event,” the team writes. “The probe beam is then restored to its original form by the reverse manipulation of the dispersion. These results are a significant step towards the development of full spatio-temporal cloaking.”

If the period of time during which the effect can be achieved is extended, the system may provide a new way for computer networks to be monitored and attacked. The team estimates the effect could be stretched to a single second, long enough to allow code injection, most effectively in a quantum-computing system. One catch: the machinery needed to accomplish this feat using their current scheme would have to be 18,600 miles long.

via The Register