Scientists Demonstrate First Successful Test Of “Time Cloaking”

First Demonstration of Time Cloaking

Physicists have created a “hole in time” using the temporal equivalent of an invisibility cloak.

kfc 07/14/2011

  • 40 Comments

Invisibility cloaks are the result of physicists’ newfound ability to distort electromagnetic fields in extreme ways. The idea is steer light around a volume of space so that anything inside this region is essentially invisible.

The effect has generated huge interest. The first invisibility cloaks worked only at microwave frequencies but in only a few years, physicists have found ways to create cloaks that work for visible light, for sound and for ocean waves. They’ve even designed illusion cloaks that can make one object look like another.

Today, Moti Fridman and buddies, at Cornell University in Ithaca, go a step further. These guys have designed and built a cloak that hides events in time.

Time cloaking is possible because of a kind of duality between space and time in electromagnetic theory. In particular, the diffraction of a beam of light in space is mathematically equivalent to the temporal propagation of light through a dispersive medium. In other words, diffraction and dispersion are symmetric in spacetime.

That immediately leads to an interesting idea. Just as its easy to make a lens that focuses light in space using diffraction, so it is possible to use dispersion to make a lens that focuses in time.

Such a time-lens can be made using an electro-optic modulator, for example, and has a variety of familiar properties. “This time-lens can, for example, magnify or compress in time,” say Fridman and co.

This magnifying and compressing in time is important.

The trick to building a temporal cloak is to place two time-lenses in series and then send a beam of light through them. The first compresses the light in time while the second decompresses it again.

But this leaves a gap. For short period, there is a kind of hole in time in which any event is unrecorded.

So to an observer, the light coming out of the second time-lens appears undistorted, as if no event has occurred.

In effect, the space between the two lenses is a kind of spatio-temporal cloak that deletes changes that occur in short periods of time.

The device has some limitations. The Cornell time cloak lasts only for 110 nanoseconds–that’s not long. And Fridman and co say the best it can achieve will be 120 microseconds.

But it’s early days yet. Given the rapid development of spatial cloaks, it’d be a brave man who’d bet on this being the last word.

Fridman and pals have clearly made themselves an interesting toy but they modestly refrain from speculating about the applications for their time cloak.

However, that’s a task well suited to readers of the Physics arXiv Blog. If you have any suggestions, leave them here.

Ref: arxiv.org/abs/1107.2062: Demonstration Of Temporal Cloaking

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2 Comments

  • 175 Days Ago
  • 07/14/2011

Time cloaking

With multiple GHz processors and optical computing, small holes in time may provide nefarious types…like major financial firms, just what they need to manipulate markets by inserting or deleting “real time” transactions from within the holes. Paranoia? Look what they do in real time now.

Reply

D64

2 Comments

  • 174 Days Ago
  • 07/15/2011

Re: Time cloaking

question. would a microprocessor inside this time cloak be able to run infinite processes or zero? for instance put a decryption algorithm into it somehow. also, check out the movie, “Primer”

Reply

doanwon

76 Comments

  • 174 Days Ago
  • 07/15/2011

Re: Time cloaking

I think this works in masking the visual sense when the observer is suddenly seeing something that is occurring because the light–which is the event–has not been released by the cloak.  The light has been trapped for a brief period of time.  It’s like a delay but in the visual sense.  So you can’t really be out of the time dimension.  You can only fool the visual observer.

Stock transactions are rigged already.  The high levels get near immediate electronic event reporting while those day traders and lower in the food chain get delayed transactions.

Reply

Unhinged

2 Comments

  • 173 Days Ago
  • 07/16/2011

Re: Time cloaking

If I was correct in the reading of this article, it was the bending of light in order to hide a particular instance or event. Not bending time itself around space, rather, bending light in time and space. Was I wrong in what I read?

If I am right, all you are doing is hiding an event for nano seconds. assuming someone could use this to hide a transaction, you will still see the before and after and can make a pretty sure observation of what just actually happened. Only when long periods of event time are ‘cloaked’ should you start to worry about financial transactions.

Reply

D64

2 Comments

  • 173 Days Ago
  • 07/16/2011

Re: Time cloaking

so its a kind of ultrasonic vibration that causes visible light distortion. kind of like looking across a hot brick wall or road, the heat seems to ‘eat’ the light and hide what is in line? I’m not so convinced about their claims about making one object look like another.

Reply

Pooua

4 Comments

  • 175 Days Ago
  • 07/14/2011

Stasis Box

Plenty of science fiction stories revolve around the stasis box, including at least one “Star Trek” book. Of course, those envisioned a field that lasted much longer than a fraction of a second.

If nano- to milliseconds are the best we can do, this device might still be useful for researching particle physics, perhaps by hiding (occulting) one affect to reveal a subtler affect? Does it affect radioactive decay? Perhaps this could be useful for image processing? Perhaps it could be used as a purer form of signal delay, one that wouldn’t distort as much as current designs.

If we ever get to the point that we could stop or slow time in a small region for more than a few days, it could really help with space exploration. I don’t see that the device described would do that–it appears to be more of a blotter of the recording, rather than a preventer of the passage of time–but perhaps EM waves are just a start? Perhaps this device could be applied to other sorts of waves and fields, perhaps even to gravity?

Reply

JohnStClair

11 Comments

  • 175 Days Ago
  • 07/14/2011

Use Slow Light to Cloak

Between the lenses you can insert a magnetic vortex wormhole generator to bring in low-speed-of-light hyperspace energy that has a light speed of 1 meter/second.

The generator creates negative energy to open up a wormhole between space and hyperspace.  Because negative energy has a lower potential than low-density positive hyperspace energy, the hyperspace energy will flow into this dimension between the lenses.  It is like putting a vacuum pump on the end of a garden hose.  This will increase the available cloaking time.

Furthermore, the hyperspace energy can be curved using electromagnetic fields since they are subject to the Lorentz transformation.  Thus the light can be curved around the object to be cloaked.

This concept is what Einstein, the discoverer of hyperspace, was trying to do in the Philadelphia Experiment that was covered up by the US Navy.  The Navy wanted a way to bend light around the Liberty ships so that the German U-boats would see a false image.  It resulted in the discovery of teleportation which has now been accomplished.

If I were going to cloak something, I would create a wormhole opening in front and back of the object and light will travel around the object through the throat of the wormhole.  This is the same as the wormhole elevator that we have between earth and Mars.  As the elevator ascends, it becomes wavy space-time because the spring constant of space has been decreased substantially due to the spring’s dependence on the speed of light squared and the linear mass of the universe.



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