If phenomena did not change when measured/observed then there wouldn't be a constraint. HUP is only visible when you measure a particle And measurements are subject to the observer effect. Yes but those values only exist when you measure them, you can't invent those values. It is a statement about the relationship between those values, whether you measure them or not. The HUP has nothing to do with the observer effect. This seems to be at the core of your misunderstanding. The measured values will exhibit a range as already stated. Note carefully that the HUP provides a theoretical (lower) limit to these values. We may interpret this as the time taken for the absorbtion/emission to occur. This is seen as a broadening of the perfect spectral line with half line width \Delta f leading to an associated uncertainty of time The radiation absorbed or emitted is only monchromatic (a perfectly thin line) to the extent that the molecular/atomic energy levels are themselves perfectly defined. The actual amount of the broadening depends upon the apparatus, but the mechanism can be interpreted in terms of a real world physical process. The best practical example of HUP I is in spectroscopy and occurs as spectral line broadening. Equations exist that allow accurate calculation of individual quantities, if the other one of the pair is not concerned. However we should note that the Hesienberg Uncertainty Principle not only limits how accurately we can measure certain pairs of quantities, it also limits how accurately we can calculate them. We find the same thing when we look at pairs like momentum and position: if you pin one down, the other must be spread out.Īnd Strange has already dealt with your other examples. So, we can either have a signal which is tightly defined in the frequency domain but is extended in the time domain, or we can have a signal that is tightly defined in the time domain but then spreads out in the frequency domain. ![]() For a sine wave that only lasts a short time, there is a wider range of frequencies around the signal frequency. It turns out that for a sine wave of long duration all these other frequencies are closely bundled around the signal frequency and fall off quickly outside that range. So, when we do a Fourier transform of a real-world signal we find that it contains many other frequencies. You can think of this as adding extra sine waves of different frequencies to cancel the signal out at those times. When we analyse what this means in terms of frequency, it turns out that we have to add extra frequencies to represent the fact that there is not signal in the past and none in the future. even though we think of a pure sine wave as corresponding to a single frequency (or note, like C#) that is only true if the sine wave is infinitely long (started an infinite time ago and ends an infinite time in the future).Ī real sine wave starts when we turn the oscillator on (or play the instrument) and ends some time later. In the case of a single sine wave, this will be a single frequency (the frequency of oscillation of the wave).īut. What this means is that if we have a signal that varies in time, such as a sine wave, then we can transform it to the list of frequencies that make up the signal. The most well-known (among engineers, anyway) use of Fourier transforms is to transform between the frequency domain and the time domain. I am not even going to try conceptualise this with my knowledge level, just say that hey, I'm on my way, its going to be slow, but I am coming. The observer effect occurs in all areas of science. ![]() Or for example, you can't know the inside of a tree without 'cutting it down'. Wildlife is often very sensitive for the presence of humans. In clinical trials to test drugs/supplements/therapies the observer effect can cause placebo-effects. Placebo-controlled studies are a way of testing a medical therapy in which, in addition to a group of subjects that receives the treatment to be evaluated, a separate control group receives a sham "placebo" treatment which is specifically designed to have no real effect. ![]() The Hawthorne effect (also an observer effect) is a reaction in which individuals modify an aspect of their behavior in response to their awareness of being observed. It seems that observer effect 'caused' the uncertainty, wave-particle duality.the seemingly randomness.Īlso, the observer effect is not necessary linked to physics. When you observe something, you change the phenomenon. In those experiments you need to observe stuff (via measuring devices). Physics is what we say of the universe trough experiments. Those detectors detect photons and in doing so, they stop the wave. Like when you use detectors in a double slit experiment. The observer effect is about how our measurements affect what we are trying to measure
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