Survey shows physicists can't agree on fundamental questions about quantum mechanics

[bananas]

http://phys.org/news/2013-01-survey-physicists-fundamental-quantum-mechanics.html

Survey shows physicists can't agree on fundamental questions about quantum mechanics

January 23, 2013 by Bob Yirka


Credit: arXiv:1301.1069 (quant-ph)

(Phys.org)—A trio of physicists has uploaded a paper to the preprint server arXiv describing the results of a survey passed out to attendees at a physics conference held in 2011: Quantum Physics and the Nature of Reality. The purpose of the survey was to find out how much agreement or disagreement there is in the physics community regarding the most fundamental ideas of quantum mechanics – surprisingly, the results showed that there is still very little consensus among physicists regarding some of its most basic principles.

Quantum mechanics at its heart is the study of the building blocks of the universe – what they are and how they work together to form reality as we are able to interpret it. Its ideas were first developed almost a century ago with such notables as Albert Einstein and Niels Bohr developing theories and debating ideas such as whether particles exist at certain places at certain times, or whether they move around constantly with a probability of being someplace at a given moment. The second idea famously led Bohr to conclude that if that were the case than the universe is indeterminate and at its base probabilistic. Refusing to believe such a possibility could be true, Einstein responded with perhaps his most famous quote that "God does not play dice with the universe." Now, nearly a century later, modern physicists are still just as divided. In the survey, just 42 percent of respondents agreed with Bohrs' assertions – the rest were divided among several other theories. Also likely surprising to those outside the physics community, a full 64 percent of those who bothered to respond to the survey said they believe Einstein's view of the universe "is wrong."

Another idea that appears to still vex the modern physicist is whether quantum objects have the same physical properties as they do when measured. Just over half thought so. Also there is the ongoing argument about the probability of a true quantum computer coming to pass, and if it ever does, when that might happen. The largest number, 42 percent said they believe it will happen 10 to 25 years from now, 30 percent said it would come after that, while just 9 percent said they thought it might happen before then.

Based on the results of the survey, it appears Richard Feynman was right when he once responded to a reporter's question about how well quantum mechanics is understood by saying that "anyone who claims to understand quantum theory is either lying or crazy."

More information: A Snapshot of Foundational Attitudes Toward Quantum Mechanics, arXiv:1301.1069 [quant-ph] http://arxiv.org/abs/1301.1069

[bananas]

1. Question 1: What is your opinion about the randomness of individual quantum events?

Question 1: What is your opinion about the randomness of individual quantum events
(such as the decay of a radioactive atom)?

a. The randomness is only apparent: 9%
b. There is a hidden determinism: 0%
c. The randomness is irreducible: 48%
d. Randomness is a fundamental concept in nature: 64%

Although we did not elaborate on the meaning of the word "apparent" in the provided answer, the
distinction between the first and the second answer becomes clear when one contrasts the Everett
interpretation with hidden-variables theories such as the de Broglie-Bohm interpretation. In the
Everett interpretation, randomness is an apparent effect relative to a branching observer, with the
global wave function (containing all branches) evolving deterministically according to the Schrodinger
equation. This does not match the notion of a "hidden determinism," which is commonly associated
with ideas such as hidden variables, deterministic mechanisms underlying the occurrence of objective
quantum events, and (as in the de Broglie-Bohm interpretation) the deterministic motion of physical
constituents. In our poll, none of the participants favored the de Broglie-Bohm interpretation, but
there was a fair amount of support for the Everett interpretation (see Question 12). This may explain
why no votes were cast in favor of a hidden determinism, while the idea of apparent randomness
found several supporters.

[intaglio]

2. D'uh, thats because its uncertain

do I need this?


(answer: I need sarcasm because of Poe's Law)

[TexasTowelie]

3. Why is the sum of the numbers in the chart equal to 90%?

Is there some other option not listed or is it the uncertainty principle?

[bananas]

4. They permitted multiple answers per question to be checked.

Some people might check off multiple answers, some might not check off any.

For some questions, the total can be greater than 100%;
for example, question 1 totals to 121%.

From the paper:

We permitted multiple answers per question to be checked,
because in many cases the different answers were not, and could not be, mutually exclusive.

<snip>

Also, we were certainly aware of the fact that the
multiple-choice format can sometimes obliterate the all-important nuances: two people may check
the answer "local realism is untenable," and yet mean completely different concepts by each word
in this sentence.

[tama]

5. 1. Quantum information is a breath of fresh air for quantum foundations (76%)

Quantum informational approaches[33] have attracted growing support.[34][35]. They subdivide into two kinds[36]
Information ontologies, such as J. A. Wheeler's "it from bit". These approaches have been described as a revival of immaterialism[37]
Interpretations where quantum mechanics is said to describe an observer's knowledge of the world, rather than the world itself. This approach has some similarity with Bohr's thinking.[38] Collapse (also known as reduction) is often interpreted as an observer acquiring information from a measurement, rather than as an objective event. These approaches have been appraised as similar to instrumentalism.

The state is not an objective property of an individual system but is that information, obtained from a knowledge of how a system was prepared, which can be used for making predictions about future measurements. ...A quantum mechanical state being a summary of the observer’s information about an individual physical system changes both by dynamical laws, and whenever the observer acquires new information about the system through the process of measurement. The existence of two laws for the evolution of the state vector...becomes problematical only if it is believed that the state vector is an objective property of the system...The “reduction of the wavepacket” does take place in the consciousness of the observer, not because of any unique physical process which takes place there, but only because the state is a construct of the observer and not an objective property of the physical system[39]

http://en.wikipedia.org/wiki/Interpretations_of_quantum_mechanics#Quantum_information_theories

[Orrex]

6. Whew! This debate actually offers me a quantum of solace.

[Duppers]

7. Feynman is right

and the fundamental problem isn't whether or not god plays dice, but figuring out what game we insist on bringing dice to.

We really need a better understanding of quantum.