A Mathematical Proof That The Universe Could Have Formed Spontaneously From Nothing — The Physics arXiv Blog — Medium

A Mathematical Proof That The Universe Could Have Formed Spontaneously From Nothing — The Physics arXiv Blog — Medium: The new proof is based on a special set of solutions to a mathematical entity known as the Wheeler-DeWitt equation...

In each of these cases, they find a solution in which the bubble can expand exponentially and thereby reach a size in which a universe can form—a Big Bang...

New fundamental limitation restricts position accuracy of quantum objects

New fundamental limitation restricts position accuracy of quantum objects: In the new study, Busch and Loveridge have analyzed Ozawa’s model and found that, contrary to Ozawa’s conclusion, momentum conservation does in fact limit the accuracy and repeatability of position measurements: they have shown that good accuracy and repeatability of a position measurement can only be achieved by using a sufficiently large apparatus.

The researchers also developed an alternative model that identifies a particular condition underlying the WAY theorem: the so-called Yanase condition, which stipulates the compatibility of the indicator variable of the apparatus with the conserved quantity. This alternative model shows that, if it were allowed to disregard and violate the Yanase condition, position measurements could be done with arbitrary accuracy, even with a small apparatus. However, if one tries to exploit this escape route from the WAY theorem, one is only faced by the puzzling prospect of the same limitation reappearing for the apparatus indicator variable.

Best-ever quantum measurement breaks Heisenberg limit - physics-math - 23 March 2011 - New Scientist

Best-ever quantum measurement breaks Heisenberg limit: They used a beam of photons to measure the small magnetic field produced by a gas made up of a million ultra-cold rubidium atoms. Normally, the spin of each photon would rotate by a certain amount, thanks to its interactions with the magnetic field of the atoms. But the frequency of the photons was chosen so that the photons also interacted with each other when they were in the gas, so that the presence of one photon altered the way a second behaved. These interactions led to a measurement accuracy that grew in proportion to N3/2 - greater than Heisenberg's limit...

Blog: Heisenberg’s Uncertainty Principle Still Certain - Science News

Blog: Heisenberg’s Uncertainty Principle Still Certain - Science News: "An entangled quantum memory could hold information about a particle that could be measured to reveal the particle’s position perfectly, and information that could be measured to reveal the momentum perfectly. “So we can have a memory which stores both the position and the momentum,” Colbeck says...

If we stopped here, Heisenberg might get a little shifty down there. But there’s a caveat, and it’s a big one: “Although the memory stores both the position and the momentum, we can only read out one of the two,” Colbeck says."