What constitutes a QM observation?

  • Context: Graduate 
  • Thread starter Thread starter Glenn
  • Start date Start date
  • Tags Tags
    Observation Qm
Click For Summary

Discussion Overview

The discussion revolves around the concept of observation in quantum mechanics, particularly focusing on what constitutes an observation or measurement. Participants explore definitions, implications, and various theories related to the quantum mechanical measurement problem.

Discussion Character

  • Debate/contested
  • Conceptual clarification
  • Exploratory

Main Points Raised

  • Some participants note that 'measurement' lacks a precise definition in quantum mechanics, with one suggesting it may be defined as "an irreversible change to the measurement apparatus."
  • There is a mention of "conscious" or "intelligent" observations, prompting a request for clearer explanations regarding the nature of observation.
  • One participant states that an observer is the individual making the measurement, highlighting the complexity of the quantum mechanical measurement problem without a definitive resolution.
  • Another participant suggests that measurements are considered in closed systems, where interactions affecting the outside imply a measurement has occurred.
  • Questions arise about whether subatomic particles can cause the collapse of their own wave function, with one response indicating that interactions with the environment can lead to wave function collapse, referencing decoherence.
  • A theory of spontaneous collapse is mentioned, where wave functions collapse similarly to radioactive decay, although attempts to detect such phenomena have not succeeded.

Areas of Agreement / Disagreement

Participants express differing views on the nature of observation and measurement in quantum mechanics, with no consensus reached on definitions or implications. The discussion remains unresolved with multiple competing perspectives.

Contextual Notes

Limitations include the ambiguity surrounding the definitions of measurement and observation, as well as the unresolved nature of the quantum mechanical measurement problem. The discussion also reflects varying interpretations of closed systems and their implications for measurements.

Glenn
When discussing quantum mechanics, what constitutes an observation?

-Glenn
 
Physics news on Phys.org


Originally posted by Glenn
When discussing quantum mechanics, what constitutes an observation?

-Glenn

'Measurment' is the temr usually used, unfortunately there is no precise definition for what constitutes a measurement apparatus and thus a measurment(this is known as the quantum mechanical measurement). The best definition is probably: "an irrevesrible change to the measurmewnt apparatus".
 
I guess I am still not clear on the "observation" part of all this. In a book I am reading, the author is repeatedly referring to them as "conscious" observations, or "intelligent" observations.

Is there a clearer explanation?

Thanks,
Glenn
 
An observer is the person who makes the measurment. It's a sticky subject as there are many theories on how to resolve the quantum mechanical measurment problem, but no defintive answer.
 
Generally, you consider closed systems. Anything inside that closed system that is made to affect something outside the system (therefore making it no longer "closed") is a measurement.

- Warren
 
Can a subatomic particle, atom, molecule, or larger cause the collapse of its own wave function?

-Glenn
 
No, but its interaction with things around it can. Look up decoherence.
 
Generally, you consider closed systems. Anything inside that closed system that is made to affect something outside the system (therefore making it no longer "closed") is a measurement.

I don't quite understand this. How does something inside a closed system affect something outside the system? After all, this seems contradictory to the word closed. Seems like a tongue twister to me. :P
 
Originally posted by Glenn
Can a subatomic particle, atom, molecule, or larger cause the collapse of its own wave function?

-Glenn

In convential quantum mechanics no, but there is a theory of spontaneous collapse where in a manner simlair to radioactive decay wavefunctions of particles spopntaously collapse, howvere attempts to detect any spontaneous collapse have failed.
 

Similar threads

Graduate Why does QM split into two evolution types?
  • · Replies 7 ·
Replies
7
Views
919
Undergrad Why observables are represented as operators in QM?
  • · Replies 4 ·
Replies
4
Views
3K
High School Special Relativity and the Measurement Problem of QM
  • · Replies 7 ·
Replies
7
Views
2K
Undergrad States and observables in quantum mechanics
  • · Replies 5 ·
Replies
5
Views
2K
Undergrad Mean values of observables
  • · Replies 2 ·
Replies
2
Views
2K
Undergrad What is an observable exactly?
  • · Replies 3 ·
Replies
3
Views
2K
Undergrad What empirical observation supports the axiom of continuous spacetime?
  • · Replies 23 ·
Replies
23
Views
2K
Undergrad The Power of QM and QFT
  • · Replies 4 ·
Replies
4
Views
2K
Graduate Baryon CP Violation Observed at CERN
  • · Replies 7 ·
Replies
7
Views
2K
Graduate Consistency of Relativistic QM
  • · Replies 12 ·
Replies
12
Views
3K