> Because of this knowing where a particle is how fast its moving or its spin direction isnt possible.
No, that’s due to wave/particle duality leading to the uncertainty principle. There’s uncertainty in where a quantum particle exists or goes thanks to the fact that all of our measurement tools are too big and waves don’t exist at a point. Consider using a meter stick to measure the width of a piece of paper. You will have an uncertainty wave packet width of 1mm at best. That is a better analogy for uncertainty. The paper is the electron and the meter stick is the observation/measurement, where instead of 1mm it’s h/4π meter.
> And measuring one property effects the particle so the others cant be measured.
Also not true, and a common lay misinterpretation (by those who haven’t been instructed on quantum I mean). You can measure Px with certainty but not simultaneously X. You can meaaure Py with certainty but not simultaneously y. Likewise Pz and not z. You can however simultaneously measure Px without affecting the state or certainty of y,z or Py, Pz. And so on for [Py,x]=0, [Pz,y]=0 etc.
It’s only σPxσx = σPyσy = σPzσz = σEσt >= h/4π; where σPxσy = σPyσX etc = 0 believe it or not. The uncertainties are coupled to the vectors. If you want you can find absolute certainty in X momentum and y position without collapsing the wave function for Pz,z. Absolute certainty for the complete vector components or the particle as a whole is not possible.
Mathematically that looks like this: https://i.imgur.com/XbCrYh3.jpg : expectation of Δx^2 • expectation of Δp(x)^2 = h^(2)/16π^2 where <Δx^(2)> = <x^(2)> - <x>^2 , same for <Δp(x)^(2)>. For quantum systems; Scale up and these uncertainties become so small as to be negligible to the system, and we’re back in Newtonian kinematics (correspondence principle).
Let’s also take note that the form is of ΔxΔPx>=h/4π: so this means, you can measure x with certainty much higher than h/4π; for instance let’s say you measure x to a certainty of h/10^(5)π. ΔPx must therefore be required to have an uncertainty that satisfies ΔxΔPx>=h/4π where ΔPx >= h/4πΔx, or ΔPx >= h/4πh/10^(5)π >= 10^(5)/4, and that’s in kgm/s. So our uncertainty in momentum rises to 25,000 kgm/s for a certainty in position of h/10^(5)π.
It’s plain to see here that as Δx goes to zero as we would approach absolute certainty, ΔPx must go to infinity, and to absolute uncertainty. You can know exactly where a particle was and know nothing about where it will be, or you can know exactly where a particle is going and know nothing about where it was. And keep in mind without both of those you can’t model the motion. Enter the wave interpretation of quantum systems, aka Quantum Mechanics, a(less)ka Wave Mechanics, and statistical analysis of the wave function provides us a model of behavior before and after measurement within the parameters of ΔrΔPr>=h/4π.. where you actually don’t need both parameters of initial position and momentum to model the wave function through time as it’s only a first derivative with respect to time!! YAY! And rejoice because if it was δ^(2)/δt^2 we’d all be fucked and stuck only with experimental data and no closed form solutions.
As a side note about entanglement: consider what I’ve said about measurements collapsing the wave function: let’s say you have 2 electrons and they interact. That is, they bounce into each other and are deflected. We know from Newtonian mechanics that if we solve the current position and momentum of one particle, we can wind back time and reconstruct the collision. The consequence of this in quantum means that when you measure the physical properties of one of the entangled particles, you necessarily have measured the properties of the other particle. This collapses both waveforms, since you have gained knowledge of the system of particles through measurement. You can reconstruct b from a. Therefore you have collapsed b’s waveform as well when you measure and collapse a’s. And thus, the particles are said to be entangled at the quantum level, the same way a cue ball is paired to an 8 ball at the Newtonian level. Measuring the properties of the 8 ball necessarily tells you the properties of the cue ball.
Also interesting aside: black holes produce a pair of electrons at the event horizon boundary, where at a certain probability, one of the electrons has been pulled into the black hole, and the other released into the universe so to speak. For one instant in time, this is the ONLY truly unpaired particle in the universe.
GhostRid3r16 t1_j9pj6hp wrote
Reply to comment by Baron_Ultimax in Physicists Use Quantum Mechanics to Pull Energy out of Nothing by Vailhem
> Because of this knowing where a particle is how fast its moving or its spin direction isnt possible.
No, that’s due to wave/particle duality leading to the uncertainty principle. There’s uncertainty in where a quantum particle exists or goes thanks to the fact that all of our measurement tools are too big and waves don’t exist at a point. Consider using a meter stick to measure the width of a piece of paper. You will have an uncertainty wave packet width of 1mm at best. That is a better analogy for uncertainty. The paper is the electron and the meter stick is the observation/measurement, where instead of 1mm it’s h/4π meter.
> And measuring one property effects the particle so the others cant be measured.
Also not true, and a common lay misinterpretation (by those who haven’t been instructed on quantum I mean). You can measure Px with certainty but not simultaneously X. You can meaaure Py with certainty but not simultaneously y. Likewise Pz and not z. You can however simultaneously measure Px without affecting the state or certainty of y,z or Py, Pz. And so on for [Py,x]=0, [Pz,y]=0 etc.
It’s only σPxσx = σPyσy = σPzσz = σEσt >= h/4π; where σPxσy = σPyσX etc = 0 believe it or not. The uncertainties are coupled to the vectors. If you want you can find absolute certainty in X momentum and y position without collapsing the wave function for Pz,z. Absolute certainty for the complete vector components or the particle as a whole is not possible.
Mathematically that looks like this: https://i.imgur.com/XbCrYh3.jpg : expectation of Δx^2 • expectation of Δp(x)^2 = h^(2)/16π^2 where <Δx^(2)> = <x^(2)> - <x>^2 , same for <Δp(x)^(2)>. For quantum systems; Scale up and these uncertainties become so small as to be negligible to the system, and we’re back in Newtonian kinematics (correspondence principle).
Let’s also take note that the form is of ΔxΔPx>=h/4π: so this means, you can measure x with certainty much higher than h/4π; for instance let’s say you measure x to a certainty of h/10^(5)π. ΔPx must therefore be required to have an uncertainty that satisfies ΔxΔPx>=h/4π where ΔPx >= h/4πΔx, or ΔPx >= h/4πh/10^(5)π >= 10^(5)/4, and that’s in kgm/s. So our uncertainty in momentum rises to 25,000 kgm/s for a certainty in position of h/10^(5)π.
It’s plain to see here that as Δx goes to zero as we would approach absolute certainty, ΔPx must go to infinity, and to absolute uncertainty. You can know exactly where a particle was and know nothing about where it will be, or you can know exactly where a particle is going and know nothing about where it was. And keep in mind without both of those you can’t model the motion. Enter the wave interpretation of quantum systems, aka Quantum Mechanics, a(less)ka Wave Mechanics, and statistical analysis of the wave function provides us a model of behavior before and after measurement within the parameters of ΔrΔPr>=h/4π.. where you actually don’t need both parameters of initial position and momentum to model the wave function through time as it’s only a first derivative with respect to time!! YAY! And rejoice because if it was δ^(2)/δt^2 we’d all be fucked and stuck only with experimental data and no closed form solutions.
As a side note about entanglement: consider what I’ve said about measurements collapsing the wave function: let’s say you have 2 electrons and they interact. That is, they bounce into each other and are deflected. We know from Newtonian mechanics that if we solve the current position and momentum of one particle, we can wind back time and reconstruct the collision. The consequence of this in quantum means that when you measure the physical properties of one of the entangled particles, you necessarily have measured the properties of the other particle. This collapses both waveforms, since you have gained knowledge of the system of particles through measurement. You can reconstruct b from a. Therefore you have collapsed b’s waveform as well when you measure and collapse a’s. And thus, the particles are said to be entangled at the quantum level, the same way a cue ball is paired to an 8 ball at the Newtonian level. Measuring the properties of the 8 ball necessarily tells you the properties of the cue ball.
Also interesting aside: black holes produce a pair of electrons at the event horizon boundary, where at a certain probability, one of the electrons has been pulled into the black hole, and the other released into the universe so to speak. For one instant in time, this is the ONLY truly unpaired particle in the universe.