From:
http://www.uq.edu.au/news/article/2015/02/quantum-reality-check

9 February 2015

Schrödinger’s cat highlights a long-standing dilemma in quantum mechanics: is the cat really alive and dead, or is the weirdness just in our head?

Researchers at The University of Queensland have now made major progress in answering this question.

Using four-dimensional states of photons, and subjecting them to very precise measurements, they ruled out the popular view that describing the cat as dead and alive is just due to a lack of knowledge about its real state.

As with all objects in quantum physics, the cat is described by the quantum wavefunction.

Dr Alessandro Fedrizzi, from the UQ School of Mathematics and Physics (SMP), said that although the quantum wavefunction is our central tool for describing physical systems in quantum mechanics, it is still unclear what it actually is.

“Does it only represent our limited knowledge about the real state of a system, or is it in direct correspondence with this reality?” he said.

“And is there any objective reality at all?”

This debate has remained purely theoretical for decades, until three teams of quantum theorists — including co-authors UQ’s Dr Cyril Branciard and Dr Eric Cavalcanti from The University of Sydney — recently proposed experimental tests to answer this question.

Lead author and UQ PhD student Mr Martin Ringbauer said that the new approach tests whether the competing interpretations of the wavefunction can explain why we cannot tell quantum states apart with certainty, which is a central feature of quantum mechanics.

“Our results suggest that, if there is objective reality, the wavefunction corresponds to this reality,” Mr Ringbauer said.

In other words, Schrödinger’s cat really is in a state of being both alive and dead….

The study can be found at http://dx.doi.org/10.1038/nphys3233

esselte said:

From:
http://www.uq.edu.au/news/article/2015/02/quantum-reality-check

9 February 2015

Schrödinger’s cat highlights a long-standing dilemma in quantum mechanics: is the cat really alive and dead, or is the weirdness just in our head?

Researchers at The University of Queensland have now made major progress in answering this question.

Using four-dimensional states of photons, and subjecting them to very precise measurements, they ruled out the popular view that describing the cat as dead and alive is just due to a lack of knowledge about its real state.

As with all objects in quantum physics, the cat is described by the quantum wavefunction.

Dr Alessandro Fedrizzi, from the UQ School of Mathematics and Physics (SMP), said that although the quantum wavefunction is our central tool for describing physical systems in quantum mechanics, it is still unclear what it actually is.

“Does it only represent our limited knowledge about the real state of a system, or is it in direct correspondence with this reality?” he said.

“And is there any objective reality at all?”

This debate has remained purely theoretical for decades, until three teams of quantum theorists — including co-authors UQ’s Dr Cyril Branciard and Dr Eric Cavalcanti from The University of Sydney — recently proposed experimental tests to answer this question.

Lead author and UQ PhD student Mr Martin Ringbauer said that the new approach tests whether the competing interpretations of the wavefunction can explain why we cannot tell quantum states apart with certainty, which is a central feature of quantum mechanics.

“Our results suggest that, if there is objective reality, the wavefunction corresponds to this reality,” Mr Ringbauer said.

In other words, Schrödinger’s cat really is in a state of being both alive and dead….

The study can be found at http://dx.doi.org/10.1038/nphys3233

Of course it isn’t. The cat knows if it is alive, and if it is in a state where it doesn’t know, then it is dead.

Even if we dispute that cats actually have such awareness, it’s a red herring anyway. There has been an interaction (or not) between a quantum particle, and a non-quantum object, which has a definite outcome, whether human or cat observes it or not.

>Using single photons

There’s the problem. A cat is a complex macroscopic organism whose functioning can’t meaningfully be modelled by “limited distinguishability of non-orthogonal quantum states”.

esselte said:

From:
http://www.uq.edu.au/news/article/2015/02/quantum-reality-check

9 February 2015
Schrödinger’s cat highlights a long-standing dilemma in quantum mechanics: is the cat really alive and dead, or is the weirdness just in our head?

…

In other words, Schrödinger’s cat really is in a state of being both alive and dead….
The study can be found at http://dx.doi.org/10.1038/nphys3233

This looks like just another unnecessary study on Bells inequality.

Did they say anything about what causes the wavefunction to collapse? That’s the most important factor, and although it has been the subject of numerous experiments I’ve never seen a definitive answer – just umpteen hypotheses. A good experiment could easily decide between those different hypotheses.