The Role of the Observer in Quantum Phenomena

Stephen M. Barr (Univ. of Delaware): "The Role of the Observer in Quantum Mechanics"
Delivered at the second conference of Society of Catholic Scientists at the Catholic University of America, June 8-10, 2018. Re-recorded in the Fall of 2018.
More information about the Society of Catholic Scientists is available at www.catholicscientists.org.

[@andrewlawrence2185]

Thank you Doctor Barr! You spoke with me and my colleagues virtually in the diocese of Peoria today. I loved your lectures!

[@NyleBrown]

An excellent discussion of observer based quantum mechanics. The "many worlds" view of reality should be viewed as the "many universes" perspective.

[@octoberride]

The last 10 minutes were very informative and persuasive against many worlds hypothesis. Great video.

[@john-paulgies4313]

The more I reflect on the thought experiments and paradoxes of quantum mechanics, the more I am inclined to account for all its "weirdness" as a mere consequence of one thing: the fact that, at this scale, direct measurement is not possible (as expressed by the Heisenberg principle of uncertainty).

[@TheJRaulet]

Also, the cat being dead and alive at the same time in the Schrodinger thought experiment is not just a way to see things that doesn’t necessarily correspond to reality but an important feature of quantum Mechanics. In fact, Quantum computing is exactly based on that assumption; it is basically letting the possibly dead cats and the possibly living cats interact with each together and only observe the result these interactions...

[@TheJRaulet]

That is such a nice and clear presentation of Quantum Mechanics! My only comment on it is that for me, the notion that there is such a thing as the collapse of the wave function is just a matter of point of view. The so called Heisenberg cut is just the line that states the observation point. The observer being a human or a device is immaterial. There is no special status required here for the measurement being done by a sentient being or a cat being killed by a special device following the outcome of an observation result. The moment you are doing an observation or a measurement on a system, you become yourself entangle with that system and for a different observer, you are now part of a new larger system (you and the system you are observing) that can be described by its own Schrodinger equation. So there is a need here for a notion of the relativity of the observation. At least only if we stick to the Copenhagen interpretation of Quantum mechanics...

[@NyleBrown]

Exactly. There is no need for any special status for an apparatus used in making the observation. It could be nothing more than the lens of the biological eye or the detector of cosmic radiation. In a practical sense the ability to retain the result of the observation and ability to transmit that information to some other observer. The consensus of many observers reviewing the information collected will determine its validity.

[@tommore3263]

It is increasingly clear to me that the atheistic materialist is the other religious fanatic in the room.

[@markb3786]

desperate and an insecure false equivalency.

[@patricksee10]

great explanation, very clear, thanks Stephen

[@miguelaplanas]

Excellent presentation.

[@trulybengali]

It was so nice to see you after such a long time Dr. Barr.

[@tommore3263]

Wonderful stuff sir. Thanks so much for your dedication.

[@NyleBrown]

I contend the definition of an observer is more than having the ability to measure the outcome of an event. The observer must also have the capability to store the information observed plus the capability to communicate the measurements to other observers not directly involved in the observation.

[@MissPopuri]

But if you opened up the box with the cat inside and found it empty or the box was opened and nothing was inside, we could conclude that you cannot keep an observer in one place of measurement if the Geiger Counter measures radiation.

[@antoniomoyal]

So gooood!

[@dieterdodelauch6899]

Very good overview, thanks!

[@DavidporthouseCoUk]

Wigner, his friend and their cats are all heavier than the Planck mass, so their Compton wavelength is shorter than the Planck length. I would suggest that the Schroedinger equation is meaningless for them, but they still have an Uncertainty Principle which is best thought of in terms of Brownian motion on an appropriate scale. The interaction between Brownian motion and the wave function can collapse the latter quite easily and is just another physical process.

[@stephenbarr8013]

There are two things wrong with this analysis. First, there is nothing wrong with an object having a Compton wavelength shorter than the Planck length. That does not mean that QM does not apply. Nor does it mean that quantum gravity effects are important. Second, while interacting with macroscopic objects can lead to decoherence, decoherence is not the same thing as wave function collapse. Decoherence is a perfectly unitary process, whereas wf collapse is not.

[@DavidporthouseCoUk]

The Brownian motion that I am planning to add in a computer simulation is not unitary. For objects heavier than the Planck mass I intend to add ordinary Brownian motion to represent the Uncertainty Principle, and see what it does to an interaction with the Dirac and Maxwell equations. At a later date I will add what I call tachyonic Brownian motion on a microscopic scale and see if I can simulate the sort of behaviour which violates Bell's inequalities using a Vernam cipher. I cannot not add any sort of Brownian motion at all, but am open to other ideas on how to make use of a random number generator in a computer simulation of quantum mechanics.

[@krzysztofciuba271]

"The interaction between Brownian motion and the wave function can collapse the latter quite easily and is just another physical process".???? What are u talking about? Again contra this "expert' fancy interpretation of QM@Copenhagen interpr.,this mathematical wave function as any statistical law ENCODES ALREADY this interaction of an "system of sth -not an individual "object!) with the measuring device! Your "w.f." interacts only in your ..imagination

[@krzysztofciuba271]

@@DavidporthouseCoUk better learn about the scientific semantics (A.Tarski,AD 1938) how to use properly both terms and signs (plus equations ) before making models and fancy calculations

[@mintusaren895]

Quanta. Orinal is gang. INDIAN Words jhanke jhanke, thoda jhankar dekho.

[@Yossarian.]

.....Let's use modern science to prove god exists?. ...utter ...utter ...utter ....bollox!

[@krzysztofciuba271]

It is supposed to be an argument contra physicalism (or materialism) but it is a typical physicist's ignorance not the methodology of science favouring so-called observer as if "encoded: in QM equation- a total semantic horror! Modern physics only proves that old classic equations cannot explain a new experimental data; therefore one needs a "better" equations.An observer (with mind and soul) is assumed to exist in any scientific inquiry: the relation object (of inquiry) -subject (the subject, only a person that can do it). A measuring device is not an observer - plain semantics!! Not mysteries and paradoxes with BS junk equations with the function of Shrodinger Cat's superposition states or the universe or an observer -they have no idea what can be quantized or described in symbols (of logic, math)! Science is not for or contra God (itis existence): it only clarifies the rationality of the world and order of the Universe requires a Mind (Programmer or God; the least action principle, non-contradiction principle- expressed in Wisdom 11;20, 2 cent.BCE).The Global Akademia Now ignorance of Aristotle,4cent BCE, classic and modern logic esp. the semantics (of A.Tarski,1936 though in formal sciences but easy to apply to any science)!

[@Yossarian.]

@@krzysztofciuba271 ....really? ...so does that mean you believe in God? Or you don't believe in God?

[@krzysztofciuba271]

@@Yossarian. I do not believe; I know he exists and talks with me everyday. U "fool don't know it"(psalm 53:1).I am his messenger, angel of death,esp. Satanic forces in Church and Akademia- one proof , the case of Rev.Fr.A.Guindon,O.M.I,proffersor @"father" of "same sex marriage legalization" (L'osser.Rom.5ii 1992). Plus I doubt u have a clue about the divine theorems of K.Godel and A.Tarski (AD 1931@1933on proof and truth)>if u are not in a cave u can easily check it

[@Yossarian.]

@@krzysztofciuba271 ...so you actually hear his voice? ...and I'm assuming he hears your voice?

[@Yossarian.]

@@krzysztofciuba271 you're right ...I've no idea about the devine theorems of Godel (whatever they might be) ...and even if I did, I doubt they would provide substantial proof for *A* god, anymore than the ideas contained and presented in Adam Wallaces book, How to catch a leprachaun, providing proof for the existence of the little green clad mischievous gold rich fellows of Irish mythology. ... You can quote all the logical theorems you like in trying to prove gods existence, but unless you can get him to talk to all of us, the way you claim he talks to you, then I'm afraid it's all just words and not proof.