Trying to understand Measurement / Detection

[Widdekind]

Quantum Wave Function "collapse", upon Measurement / Detection, always involves some signal, which "registers" the WFC / M / D, to the rest of our space-time.

 

WFC / M / D often involves a spatial localization, into a vacant-and-available bound state, in an attractive potential well. Yet, charged particles, accelerating due to their interactions, can also emit energy-carrying photons.

 

Generalizing, WFC / M / D seems to involve "Force Interactions" (e.g., EM), and the creation-and-emission (or absorption-and-destruction) of the corresponding Force Carriers (e.g., photons). Therefore, total particle number is not conserved.

 

To wit, WFC / M / D seems to involve multi-particle interactions, and is not something isolated systems spontaneously undergo, on their own. Crudely, the "total energy", of a system of particles, as expressed by their "system Hamiltonian" H = KE₁ + KE₂ + ... + V, is constant, during typical Type II evolution, wherein energy is only "spread around", or "diffused amongst", or exchanged between, the interacting quantum particles. In such circumstances, interacting-and-energy-exchanging particles can "Entangle".

 

Yet, during Type I evolution, energy is utterly expelled from the system (or, incorporated into the system), and so the "total energy" discontinuously changes. Thus, Type I WFC / M / D seems to involve a system of force-interacting particles, which "changes gears", "down-shifting" into a lower energy mode (or, "up-shifting" to a higher energy mode), such that [math]H_i \ne H_f[/math]. In such circumstances, the particles "WF Collapse".

 

In sum, there seems to be some sense of:

 

Type I

evolution

discontinuous "quantum jump"

Wave Function "

collapse

"

discontinuous energy change

energy not conserved

particle number not conserved:

Force-Carrier particle created/destroyed, effecting "

registration signal

" to surrounding space-time

 

Type II

evolution

continuous

energy exchanged "in house" only

energy conserved

Wave Functions "

Entangle

"

Are these statements appropriate ? Seemingly, if so, then there is no such thing as a "partial registration signal". To wit, by the time that some energy-carrying photon is created (say), and expelled from the system as a registration signal to the rest of our cosmos, then that system has already undergone WFC / M / D. Thus, there is never any such thing, as a "partial registration" -- such signals are either sent, or not sent, in their entirety. To wit,

 

Wave Function Collapse = Measurement = Detection = Registration

WFC = M = D = R

Otherwise, there seems to be the sense of potentially "infinite recursions", of Entanglements, with partially-present prior Registration-Signals, with no "out", to "clear the table", for a "new hand of cards".

 

Also, and perhaps more importantly, you would, then, actually have "half photons" (or, generally, "partial Force Carriers"), whose total Wave Function, integrated over all space-time, would only add up to some fraction, less than one whole, of a particle. Thus, WFC, upon M/D, seems to preserve the "Quantum Integrability", of quantum particles (specifically, the Force-Carriers created/destroyed, in the process).

Edited July 13, 2011 by Widdekind

[swansont]

Type I

evolution

discontinuous "quantum jump"

Wave Function "

collapse

"

discontinuous energy change

energy not conserved

particle number not conserved:

Force-Carrier particle created/destroyed, effecting "

registration signal

" to surrounding space-time

 

Example?

[Widdekind]

Example?

 

Please consider, a 'cosmological photon', crossing our cosmos, through cosmological distances, over cosmological time-scales. For billions of years of time, through billions of light-years of space, that photon exists in "phantasmal form", "ghost evolving" across the cosmos, according to the Type II von Neumann evolution, of its 'wave function' (WF), governed by the SWE.

 

Then, suddenly, on the other side of space, after eons of time, that photon -- which went 'AWOL' from its emitting source system, billions of years before, billions of light-years away -- "collapses" into definite, measured, observed existence, inside some human space-surveying telescope. The WF associated with that photon vanishes; viewed as a simple quantum system qs, that same system is destroyed, violating local, "intra-system" energy conservation; even as that energy is transferred over, to the telescope.

 

 

QUANTUM STEALTH ?

 

If a simple quantum system qs, consisting of a single photon, can cross cosmological distances, over cosmological times, in "phantasmal form", without ever being detected or observed, so much as a single time; then, in theory, a (much) more complex quantum system QS could also cross our cosmos, in "ghost ethereal form". Thus, in theory, an advanced "quantum coherent space-craft" (space probe, space ship, 'star destroyer'), could "ghost evolved" its way through space-and-time, at conventional velocities (v < c) according to the SWE, but in a completely quantum-un-detected, quantum-un-observed, quantum-un-measured manner. If some 'science-fiction' be permitted, solely for sake of emphasis, an "alien invasion fleet", could "ghost out" in some distant star system; cross this cosmos, to earth; and then "pop" back into existence, with 'star destroyers' "collapsing" into observable reality, over every major earth city, simultaneously... without warning, with "quantum stealth".

 

Is such not so, in theory ??

[swansont]

How does that violate conservation of energy?

[Widdekind]

Could you "trick" a particle, into Wave-Function-Collapsing, by creating an artificial potential well; allowing the particle to 'relax' into that well; and then 'pulling the plug', and destroying the potential well, leaving the particle 'high and dry', in a spatially confined state ??

 

In-so-far as particles, to WFC into potential wells, have to be able to sense, that that potential well, is a well, not a general 'downslope gradient'; then, it seems, that particles would have to 'slosh about' some, within the well, w/ the WF scattering of the attractive center, falling backwards after propagating away, re-scattering, self-entangling (?? leading to 'self-entangled' contradictions??), before finally WFC'ing. So, WFC perhaps requires at least one "crossing time" to set up, before occurring.

Edited July 29, 2011 by Widdekind

[Widdekind]

WFC requires "one witness" ?

 

Considering collisional excitations & de-excitations, between atoms & free electrons, in inter-stellar plasmas, full-fledged energy-eigen-state changes can occur, indicating WFC, yet without the emission of any "off-to-infinity" photon, as the QM hallmark "registration signal", e.g., 13.6 eV = 91 nm photon emitted from electrons binding to protons. In the latter case, the generated-and-emitted photon acts as a "third party witness" to WFC; in the former case, by comparison, the free electron plays the role of the photon, albeit persisting through the interaction, during which it either "off-loads", or "on-loads", energy, either to, or from, the atom. So, seemingly, even if "the universe" or "the (classical) environment" can act as a WFC-inducing (large) quantum system; so, then, any (even small) quantum system, can serve as "registrant witness" to the quantum observation/detection/measurement/actualization event.