Measurement Definition and 1000 Threads

Homework Statement For a particle in an isolated system, the Hamiltonian operator has normalised eigenstates and eigenvalues u_{n}(x) and E_{n}, respectively. The operator of another variable Q has normalised eigenstates and eigenvalues \phi_{n} and q_{n}, respectively. The lowest two Q...

Hi, Im am building a measurement device to measure the speed of a fan. Essentially I have a diode on one side of the fan, and a phototransistor pointing to it on the other side of the fan. This results in an output signal resembling a square wave. I am also trying to build an circuit...

I was talking to my professor about what constitutes as a measurement and the topic of the Stern-Gerlach experiment arised. *Please don't discuss about schrodinger's cat and that funny business, I've heard it many times and I am very bored of that discussion. Please no metaphysics BS, I want...

A particular muon lives to the ripe old age of 4.5 microseconds (three half lives). As it sits in its chair, ticking off the picoseconds, it observes the Earth streaking by at 99.99999995% light speed. What will be the elapsed time of the muon's life, as measured on the Earth clock? As I...

Here is a relatively simple problem. I'm wondering if someone can give me their opinion on it or actually know experimentally if it is true. Here is the diagram: A flow of liquid (say water) is pumped through a pipe that has a reduction in diameter. You place a pressure gauge before...

Hi, Could you describe the "before the measurement" mechanism in de broglie bohm theory? Is there a real collapse during the measurement? Can we determine the particle's position in its guiding function without disturbing it? Is there any way to calculate guiding function?

I don't possesses enough knowledge of GR to know if this proposal is feasible (or even remotely possible) I would welcome any constructive criticism of the following idea for detecting Lens Thirring effect: Apparatus consists of a dense, massive sphere or disc, rotating at high velocity...

1. The problem statement: A set of measurements of a parameter x has a normal distribution with mean of 50 and standard deviation of 1. If there are a very large number of measurements, approximately what percentage of measurements would you expect to be in the range 48 < x < 50...

Homework Statement I took a Moment vs field measurement of magnetic thin film taken on a VSM. The Bs of the material is given in emus. I want to convert this to a moment value in Tesla as it is typically given in publications. Are VSM measurements actually emu/cm3 despite being given as...

Does anybody understand how this wattmeter configuration is measuring reactive power? Thanks

I did some device that should be capacitor. when i try to measure capacitance I got some capacitance that varies like that:(1.5-2.5nF), but.. then i wanted to check resistance just for curiosity.. I got some result..it shows me 1.34MOhm. How it could be? As I understand it should be or...

Quantum physics texts describe how it is impossible to measure S(z) and S(x) spin components of a single electron at the same time where z represents the z axis,etc. What would happen if you try to trick nature by using a correlated pair of electons, emitted from an ion, moving in opposite...

I am curious how exactly fundamental measurements are made for subatomic particles. I am hoping someone who knows can point me to some references as to the following: 1) How is the position of a photon measured? 2) How is the position of a subatomic particle measured? 3) How is the momentum...

IQ is supposed to be the measurement of your "natural intelligence." IQ is supposed to be the measurement of your "natural intelligence." However, can your IQ vary on how much brain activity you're doing? For instance, during the Summer a person is lazy and not doing any studying or anything...

What is an observation or measurement? If it is not known exactly I would like to at least have some good appreciation of what the fuzzyness of the boundary is.

**Quick angular measurement question about moon. Thanks! I am suppose to write a calculation on finding angular measurement of the moon. Does the following make sense, and is correct?

Lets say we have a system in a 1D infinite potential well, prepared somehow with the wavefunction: (phi)=C(a-x)x. I understand that if I try to measure the system's energy, I will collapse the system to an eigen state ((psi)=Asin(n pi x/length)+Bcos(n pi x/length)), returning an eigen energy...

[b]1.I need to create an electronic system that automatically can measure and derive the IV and I-P characteristics (graph) and it must show maximum power point on the graphs. [b]2.The system must include a homemade voltage controlled electronic load that can load the solar cell with a well...

Maybe I'm biased because of the kind of projects I'm pursuing (raytracing), but I can't help feeling that for many areas, instead of defining a circle in terms of radians (or degrees for that matter), we should simply use unity and define say, a quarter of a circle as being 0.25. Obviously a...

In the two slit experiment there is an interference pattern generated whenever there are no detectors at the slits. This must mean that the wavefunction associated with the particles have not decohered. But the wavefunction must have interacted in some way with the barrier in order to produce...

I have an idea how to measure the ecliptic longitude with a sundial type device. Ecliptic longitude is a astronomical variable so I chose this forum. Suppose we have a verticle flag pole poised on the equator of the Earth. A "coordinate circle" is drawn that surrounds the flag pole, radius =...

Hi, i have a question about the radioactive behaviour of radium 226 and its dangers. The reason for my question is that I'm going to work in a town, where unfortunately the beach is polluted with radium 226. I'm concernced about this issue and want to know how dangerous this has to be...

Is it correct to say that a measurement occurs whenever a wavefunction interacts with a macroscopic object? If this is the case why does the wavefunction make a distinction between a photon detector and say a half silvered mirror used in quantum experiments. Both are macroscopic objects but in...

Hi, I have been assigned to a new task in my job where I have to investigate on measuring the distance to an object by means of optical interferometry (Michelson interferometry). I have been looking for info on the subject but have not been really lucky. I have been able to obtain the...

Hi tehre, this is my firs post here! I'm designing a complex system using a 40kHz ultrasonic transducers in distance measurement for waste container level detection. Now I have a big problem because the hot season change the air properties in temperature and humidity. Anyone may help me...

Where is the starting point of measurement of the Ecliptic Longitude, the Ecliptic Latitude, Right Ascension, and Declination?

Let's say we have photon beam with certain frequency. Now we make a choice to perform one of two noncomuting measurements, say polarization measurement in H/V basis or polarization measurement in +45°/-45° basis. After that measurement we perform frequency measurement. From QM perspective it is...

Hi, I have to make a coil.I do not know anything about its dimensions but know that it is to be used to measure magnetic field,its actually to be used in a magnetic susceptibility measurement.There are 3 coils, drive, excitation, measurement and I/p is given at 1000hz frequency. I need to...

I appologize if my questions make no sense (very likely as I do not have a physics background). 1. The uncertainty principle states that precision of measurement is identified only down to the Planck's constant. If this is so, how can one measure the speed of light with infinite precision? ANd...

I have to measure the particle velocity of sound waves in water. Which instrument to use to measure particle velocity of a sound in a specific direction. I searched but I find some anemometer setups for velocity measurements. I think they are all water flow measurement methods. Is there any...

is this a correct way to describe the MP? It means that everything is everywhere doing everything in every possible state at all times, until something conscious looks at it, then, as a result of the observer, it takes a state, which is only subject to how the observer perceives it. We only...

I have a code in Matlab where I need to measure the radiation on a specific latitude over a year. I have my time steps in hours and I am iterating over a year. I have parameters for the amount of radiation per hour in a 24 hour period, but my problem is that I want to loop this 24 iteration loop...

So, rookie question, I know, but I'm having a little trouble with the idea of wavefunction collapse as it pertains to stationary states: If a measurement of energy collapses a wavefunction into an energy eigenstate, it stays there forever (unless perturbed). But my impression is that although...

Can someone show me how to add, subtract, multiply and divide uncertainties in measurement.

The problem involves measurement in a quantum system with angular momentum. There are two parts I am struggling with. Apologies for the images, I tried to put it all in latex but failed! Part 1: http://i2.sqi.sh/s_1/1xo/part1.jpg I have found a long derivation in a book involving a...

Hello all, I've been trying to measure the resistance of a pin, which the supplier spec at around 15mohms. I am using the hp 34401 multimeter with the 4 wire method to do the measurement. Its seems to me that when I probe the tip and the base of the pin, the resistance value is not...

Experimental "measurement" of Einstein's Field Equations The question is essentially: What if we took a strictly experimentalist view, and considered a phenomenological model for gravity that is a "generalization" of EFE: R_{\mu \nu} - C_1\ g_{\mu \nu}\,R + C_2\ g_{\mu \nu} \Lambda = C_3\...

In double slit experiment of electron, we see an interference pattern when we don’t know through which slit electron has passed and we don’t see an interference pattern when we know through which slit electron has passed. Now, to identify the slit through which electron has passed, we use...

1. Suppose in Schrodinger cat thought experiment we place a camera inside the chamber which record the events happening inside the chamber. (We are not watching inside the chamber through the camera during the period of experiment. It is just for recording purpose). After one half life of...

I have a thrust producing engine and I would like to measure the thrust from it as accurately as possible without needing the use of scales, rollers, load cells, etc. Anyway a friend of mine suggested I suspend the engine from four wires so that the wires are vertical when the engine is...

Following a short discussion in another thread, I promised to start a new thread for this. I asked myself the question "how would I describe the process of measurement in a fully quantum mechanical way?" and came up with this. 1) A model for the general measuring device The aim is to have a QM...

Why does decoherence not fully solve the measurement problem? I know that must have been discussed here before a lot, maybe someone can me direct to a earlier thread or post that explains it well? I read some QM texts, but they mostly do not discuss decoherence. I know something with...

Hi all, Consider a simple harmonic oscillator in the ground state. Measuring its energy yields the ground state energy with 100% probability. Now by measuring its position (thereby changing the wavefunction) and next measuring the energy again, there is now a nonzero probability of finding...

I have a question regarding probability of quantum measurement. Consider polarized photon beam that is going through polarizer. Let's assume that beam intensity is very low so that we can consider it as separate photons going through polarizer one by one. Now if we consider any single photon...

I am a little confused about a histogram of force measurements. I was asked for my physics lab to state what the vertical axis and horizontal axis represent for a histogram of force measurements? the physics lab consists of pulling a wooden block with a force sensor to record the tension...

I am trying to figure out how to combine uncertainty (in x and y) into the standard error of the best fit line from the linear regression for that dataset. I am plotting units of concentration (x) versus del t/height (y) to get a value for the flux (which is the slope) I understand how...

If I understand correctly, a measurement affects the wave function only at the moment of measurement. In other words, if one were able to compare two wave functions, one when there were measurements, and one in which there were no measurements, the only difference would be at the meager set of...

Apparently my modern electronic home electric meter uses a 'current transformer' to measure the current in order to calculate the wattage I am using. My question: is the flux generated in the current transformer also proportional to the reactive part of the current as well as the in-phase...

Is decoherence a resolution to the issue of measurement? I have read arguments on both sides.

As the title sais... Can someone explain to me what is a non-orthogonal measurement? I searched the web by i can't find any definition