Shailesh Pincha said:I want to know the different views tried to determine electron position.
I was just thinking about the ways tried to understand electron and maybe made a mistake their. Thus I wanted to know the possible mistakes in observing electron. But you made me a lot of things clear. ThanksNugatory said:Just about all methods involve bouncing something off the electron (or bouncing the electron off of something, which is the same thing if you choose a frame in which the electron is at rest). That covers scattering, cloud chamber trails, spots on a photographic film, detector clicks, and pretty much everything else.
In some experimental setups you can get a very good idea of the momentum of the electron by passing it through a magnetic field of the way to the detector; the Lorentz force deflects the electron in a velocity-dependent way so that you can arrange that only electrons with a specific momentum make it to the detector.
However, I have this nagging suspicion that you're thinking about the Heisenberg uncertainty principle, and imagining that it says that a measurement of position has to change the momentum and vice versa. That's a 1920s-vintage misunderstanding that was abandoned as more was discovered about the mathematical basis of QM - but by then it had entered the popular imagination, and it's proven impossible to uproot it from there.
The uncertainty principle in the modern understanding says something different. If I prepare a system so that the electron is in a precisely known position I can still, if I am clever enough, devise a way of measuring its momentum to whatever degree of precision I wish. However, if I perform this experiment many times with the electron in the exact same position every time, I will get different values on the momentum on each run - and the spread of the momentum values will be given by the uncertainty principle.
But this would mean that by taking the mean of a large number of momentum measurements, I can get a definite value for the momentum, i.e. one that I can repeat by taking the mean of another large number of momentum measurements, averaging out the uncertainty.Nugatory said:However, if I perform this experiment many times with the electron in the exact same position every time, I will get different values on the momentum on each run - and the spread of the momentum values will be given by the uncertainty principle.
That's not giving you a definite value for the momentum of anyone particle, it's giving you the expectation value (loosely speaking, the mean) if you prepare a particle in a particular way, measure its momentum, then prepare another particle in the exact same way, measure its momentum, and repeat a large number of times so that you can get an average. Do remember that measuring the momentum changes the momentum, so if you perform repeated measurements on the same particle you're measuring something different every time. The only way of measuring the same thing every time so that you can calculate the mean is to set up an ensemble of identically prepared particles so that you can make one momentum measurement, unaffected by all the other measurements, on each member of the ensemble.jeremyfiennes said:But this would mean that by taking the mean of a large number of momentum measurements, I can get a definite value for the momentum, i.e. one that I can repeat by taking the mean of another large number of momentum measurements, averaging out the uncertainty.
Electron position uncertainty, also known as the Heisenberg uncertainty principle, is a fundamental principle in quantum mechanics that states it is impossible to know both the exact position and momentum of an electron at the same time.
This uncertainty is a result of the wave-like nature of electrons. According to quantum mechanics, electrons do not have a definite position, but rather exist as a probability distribution in space. This means that the more precisely we know the position of an electron, the less we know about its momentum, and vice versa.
The uncertainty in an electron's position is calculated using the Heisenberg uncertainty principle, which states that the product of the uncertainty in position and the uncertainty in momentum is always greater than or equal to a specific value, known as Planck's constant.
This principle has significant implications for our understanding of the physical world, as it challenges the classical notion of determinism, where the position and momentum of objects can be precisely known. It also plays a crucial role in the development of modern technologies, such as transistors and computer memory, which rely on the quantum behavior of electrons.
No, electron position uncertainty is a fundamental principle in quantum mechanics and cannot be overcome. However, scientists have developed techniques, such as quantum entanglement and superposition, to control and manipulate the uncertain position of electrons, leading to advancements in technology and our understanding of the universe.