Posts tagged quantum

Bruno Sanguinetti and pals at the University of Geneva in Switzerland have worked out how to generate random numbers on an ordinary smartphone using genuine quantum processes. And they say their new technique can produce random numbers at the rate of 1 megabit per second, more than enough for most security applications.

https://medium.com/the-physics-arxiv-blog/602f88552b64

Yuji Hasegawa at Vienna University of Technology in Austria and a few pals say they’ve observed a quantum Cheshire cat for the first time. These guys have performed a paradoxical experiment in which they measure the location of neutrons in one part of the set up while detecting their spin in another part. “The results exhibit the characteristics of a quantum Cheshire Cat,” they conclude.

https://medium.com/p/718c885f6a98

Using four photons, we can actively delay the choice of measurement-implemented via a high-speed tunable bipartite state analyzer and a quantum random number generator-on two of the photons into the time-like future of the registration of the other two photons. This effectively projects the two already registered photons onto one definite of two mutually exclusive quantum states in which either the photons are entangled (quantum correlations) or separable (classical correlations). This can also be viewed as “quantum steering into the past”.

http://arxiv.org/abs/1203.4834