"As if the idea of a device that makes an object seem invisible was not mind-boggling enough," begins a News and Views essay in the 5 January issue of Nature , "researchers have now demonstrated a system that can conceal an event in time." Those researchers' paper claims "a significant step towards the development of full spatio-temporal cloaking." The Washington Post highlighted the story with a front-page announcement sending readers to an interior-page news report.
The Nature "editor's summary" of the researchers' paper begins by mentioning the "limited functionality" of "spatial cloaks with the potential to hide an object within a 'hole in space,' " calling such devices the result of "remarkable progress . . . in developing materials that can manipulate electromagnetic waves in a way that is impossible with natural structures." That's the context for today's news, the "analogous, conceptually intriguing idea" of devising "a 'time cloak' that artificially creates a hole in time rather than in space, by accelerating and slowing down, respectively, the front and rear parts of a probe light beam."
The editors explain that experimenters have demonstrated "such a time cloak in a fibre-based system, in which an event that causes a clear disturbance to a probe beam appears not to occur at all when the time cloak is turned on." The effect is achieved, they say, "using a split time lens that breaks light up into its slower (red) and faster (blue) components, thereby creating a temporal gap." This cloaking takes place on a picosecond time scale.
The paper version of David Brown's Washington Post article introduces the news to the public with the headline "Event-hiding temporal cloak created by physicists" and the subhead "Manipulations called 'a big step forward,' but uses are unknown." Brown begins this way:
A team of physicists at Cornell University has created a wrinkle in time. Actually, it's more like a teeny tiny moth hole in time. Inside it things can occur that are entirely undetectable, at least to ordinary observers. It's as if they never happened.
This phenomenon, known as "temporal cloaking," is the latest addition to a world that once existed only in children's literature and science fiction—a place where objects are invisible and events are unrecorded.
The physics community let out a small gasp six years ago when researchers reported the first successful "spatial cloaking," in which light is bent around an object in a way that makes it disappear from view. The new report in the journal Nature shows how they can play with something that would seem to be even harder to manipulate: the perception of time.
Brown goes on to quote Vladimir M. Shalaev, a professor of electrical and computer engineering at Purdue University: "I think it's a big step forward. It's another example of the beauty of 'transformational optics,' which is behind all these ideas." Brown writes that though temporal cloaking "follows all the ironclad laws of physics," it's still "to some extent a parlor trick, albeit performed in a highly unusual parlor." He closes by quoting Shalaev again: "Normally when you have such a beautiful physics, it does come eventually to an interesting application."
The Wall Street Journal posted a wire service report. As of the morning of 5 January, the New York Times was silent on this topic.
Steven T. Corneliussen, a media analyst for the American Institute of Physics, monitors three national newspapers, the weeklies Nature and Science, and occasionally other publications. His reports to AIP are collected each Friday for Science and the Media. He has published op-eds in the Washington Post and other newspapers, has written for NASA's history program, and is a science writer at a particle-accelerator laboratory.
