快猫短视频

And you thought light moves fast

SO MUCH for the ultimate speed limit. 快猫短视频s in Switzerland have measured
how fast information can flow in the quantum world and have clocked it
travelling 1500 times faster than light.

The Swiss speed trap involved pairs of 鈥渆ntangled鈥 photons. Once linked, the
pair behave as one, even if the photons are on opposite sides of the Universe.
Physicists don鈥檛 think this flouts the light-speed limit enshrined in
relativity. 鈥淵ou cannot use this effect to communicate, it鈥檚 not like ordinary
information,鈥 says Wolfgang Tittel of the University of Geneva.

But the Swiss team wondered just how fast such communication could travel. So
they created an entangled pair in their Geneva lab and sent the two photons in
opposite directions along a 10.6-kilometre optical fibre.

Because the two arms of the fibre are not exactly the same length, one photon
will arrive first and will change its state when detected. This will change the
state of the other which will be detected shortly after. Hence the researchers
know they communicated in the short time between the first and second detection
and can calculate the minimum speed of that communication.

That speed was at least 4.5 脳 1011 metres per second, enough to reach the
nearest star, Alpha Centauri, in just over a day. Ordinary light would take 4.3
years.

  • Source:
    Quantum Physics e-print 0007008 at http://xxx.lanl.gov

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