entanglement

In physics, the arrow of time gets bent

An example of the hypothetical “weird time physics” that I discussed in my talk at the MTA conference. This is not (yet) “time travel” or “quantum archaeology” and should not be taken as such, but it shows that different pixels of space-time are subtly entangled.

The San Francisco Chronicle has an article by Deepak Chopra, MD and Menas Kafatos, Ph.D., on “In physics, the arrow of time gets bent.”

It seems that in the world of quantum phenomena it can appear to move backwards. Quantum physicists at the University of Vienna looked at entangled particles, which exhibit synchronized behavior no matter how far apart they are in space. As soon as one particle is measured, its exact counterpart will show up in the entangled twin state, even if they are far, far away from each other. In other words, this “action at a distance” defies the speed of light. Einstein could not accept the consequences of quantum entanglement, and so he added the word “spooky” to action at a distance.

In the quantum world, certain phenomena have arisen known as retro causation, and exactly as it sounds, a future measurement appears as if it is affecting a past event. This would be a form of entanglement that reaches backward in time, a new form of spookiness. The Viennese team worked on “delayed-choice entanglement swaps.”

Four photons, made of two entangled pairs, are produced (think of them as four tumbling dice waiting to be measured). One photon from each pair is sent to a physicist named Victor. He will be assigned the task of measuring them. The two remaining photons are put in separate packages, one sent to a physicist named Alice, the other to a physicist named Bob. The three physicists now have their sealed packages of photons that have not been measured yet.

Victor can choose between two kinds of measurements. If he decides to measure his two photons in a way such that they are forced to be in an entangled state, then Alice’s and Bob’s two photons also become entangled. But if Victor chooses to measure his particles individually, Alice’s and Bob’s photons end up in a separable state. This is a point that Einstein was stuck on. He couldn’t believe the assertion made by Bohr and Heisenberg that the mere act of measurement by an observer determines where a particle will be. But accepted quantum theory has shown that particles have no physical characteristics until they are measured. For a long time this has been true for position in space. Now it seems that where a particle is in time also depends on measurement.

Read more on the San Francisco Chronicle…

Read even more on Deepak Chopra’s blog…