Things that self collapse or self measure

[rodsika]

Can you give example of systems that self collapse? For example, is radioactive decay an example of self measurement? How about 13 billion years ago when stars were just being formed, is it an example of self measurement? Because I can't imagine how stars can form when all things are in superposition. Please give other examples where things self collapse (or self measurement) occurs without observers in the context of the orthodox Copenhagen. Thanks.

 

[Drakkith]

An observer doesn't have to be a person. An electron can observe a passing proton inside a star just fine. Observer just means something that the particle interacts with I believe. (Someone correct me if I'm wrong)

 

[StevieTNZ]

According to Euan Squires, in his book 'Conscious Mind in the Physical World':

... systems described by the Schrödinger equation, cannot themselves make measurements ...

 

[kith]

Can you give example of systems that self collapse?

Self measurement doesn't exist for quantum systems. When they are isolated, they obey Schrödinger's equation.

How about 13 billion years ago when stars were just being formed, is it an example of self measurement? Because I can't imagine how stars can form when all things are in superposition.

The superpositions are destroyed due to interactions with the environment (this process is called decoherence). The environment in this case is the electromagnetic field. An ensemble of atoms, initially in a superposition state, thus evolves into an incoherent mixture, describeable by the Boltzmann distribution.

 

[kith]

An observer doesn't have to be a person. An electron can observe a passing proton inside a star just fine. Observer just means something that the particle interacts with I believe. (Someone correct me if I'm wrong)

From a mathematical point of view, observation usually involves non-unitarian time evolution ("collapse"). Fundamental interactions, like electron-proton scattering, obey unitarian time evolution and constitute therefore no measurement.

In the Kopenhagen viewpoint, the collapse is caused by interacting with a "classical" measurement device (which as you said doesn't have to be a person).

In the Decoherence viewpoint, non-unitarian time evolution arises from interactions with an environment.

 

[rodsika]

From a mathematical point of view, observation usually involves non-unitarian time evolution ("collapse"). Fundamental interactions, like electron-proton scattering, obey unitarian time evolution and constitute therefore no measurement.

In the Kopenhagen viewpoint, the collapse is caused by interacting with a "classical" measurement device (which as you said doesn't have to be a person).

In the Decoherence viewpoint, non-unitarian time evolution arises from interactions with an environment.

So in the Big Bang. What serve as the classical measurement device to collapse
it? 13 Billion years ago. There were no humans yet. So how did the universe wave
function collapse? I can understand decoherence can turn it into mixture but
mixture is not really collapse. Collapse is differet from Mixture.

 

[Drakkith]

So in the Big Bang. What serve as the classical measurement device to collapse
it? 13 Billion years ago. There were no humans yet. So how did the universe wave
function collapse? I can understand decoherence can turn it into mixture but
mixture is not really collapse. Collapse is differet from Mixture.

An observer doesn't have to be a person. It can be whatever interacts with the particles.

 

[yoda jedi]

So in the Big Bang. What serve as the classical measurement device to collapse it? 13 Billion years ago. There were no humans yet. So how did the universe wave
function collapse? I can understand decoherence can turn it into mixture but
mixture is not really collapse. Collapse is differet from Mixture.

no observers...

http://arxiv.org/PS_cache/arxiv/pdf/1003/1003.5582v2.pdf

.

 

[rgmcc]

Would a typical modern-day Copenhagenist say that collapse occurs 'at the time of decoherence' and that collapse consists of random selection of one of the 'diagonal terms'?

 

[Jacques_L]

The ideation of "collapsing" is a pure anthropocentric fantasy.
As egocentric anthropocentrists, some ones has postulated that the time and causality in microphysics should be identical to our familiar time and causality in our macroscopical world governed by statistical emergences.
Their concept of "wave function" is a fiction engineered to represent their egocentric knowledge under the assumption that absorbers do not play any role in causality in microphysics, that in microphysics, absorbers do no exist, and only emitters and artillery exist.
The costs to pay are many, and all that fuss about "collapse" is one.

However the formalism contradicts the semantics the standard teaching wraps around.

Since the complete relativistic equation for fermions set up by Dirac in 1928, you have under you eyes the components with negative energy and negative frequencies. So since 1928 you do not need any more any magics of "collapse" to understand the convergence of any quanton wave on an absorber.