Measurement Definition and 1000 Threads

Suppose it is known that a photon has diagonal polarisation (e.g. it has just passed through a diagonal slit), then Alice comes along and measures the photon using a horizontal/vertical polarisation basis. So, I believe there is a 50% chance she will get a horizontal result and 50% chance she...

Homework Statement Hi All, I have a problem in calculating the thickness of a coating material inside a tube. The tubes inside diameter is measured before and after coating. The coating thickness is calculated by substracting the diameters and dividing by two to get the thickness of the...

The units of measurement of the SI (System International) are commonly used around the world ·· they form a coherent system usable for a variety of branches of science. But.. there's another coherent metric system that may be a better fit for many applications in chemistry and physics. The...

Hi, I am currently learning and trying to build an extended kalman filter. However I am not sure how to created the measurement matrix. The measurement matrix H is described using formula 3.6 on page 18 of this document http://www.scribd.com/doc/54702247/UAV-Design My problem is that...

Homework Statement Define measurement in the Copenhagen interpretation of quantum mechanics. Homework Equations The Attempt at a Solution In the Copenhagen interpretation of quantum mechanics, measurement changes the state of a wavefunction, that is, it collapses the wavefunction...

When we use polarisation rotators to measure certain polarisations for entangled photons, the photon usually meets a polarised beam splitter after. When we detect in the |H> or |V> basis, does that mean the photon is in |H> or |V>? What has happened to the polarisation we were measuring...

Hello, I am stuck on a pipe flow measurement problem and I would love if some excellent minds would help me out. I have a robot that sprays paint, and there is a motor pump providing the paint to it. I need to be able to measure the flow rate (velocity) of the paint going through the nozzle...

My book defines accuracy as the closeness of a measurement to the real/actual value, precision as when a set of values are consistent with each other (i.e. close to each other) and sensitivity as the smallest possible reading of an instrument (i.e. to how many decimal places it can measure)...

Hello all, Having read many threads and posts about light, it’s speed c, SR etc, the particular issue of not being able to measure the one way speed of light has always stood out and kept me very interested, so, after pondering about it for a while, I would like to propose an experimental...

I had a problem where we had to write out the sinusoidal function for the rotation of a ferris wheel. My teacher said that because the rotation was a function of time (x-axis was time), we had to use radians and not degrees. Could someone explain to me if/why you need to use radian measurement...

Hi, I was trying to measure DC link current on a switched mode power supply when I came across a quirk of my circuit. I'm using an LEM HX 03-p SP2 hall effect current transducer to measure current. I couple the output node of my current transducer to ground via a 2KΩ resistor. The device's...

Hi everybody! I'm studying this paper "Unambiguous discrimination among quantum operations" http://pra.aps.org/abstract/PRA/v73/i4/e042301 and they state that Ok, it's well known, but then I took a review of the notes to my course of quantum information and i found this not proven proposition...

Homework Statement A system in a state \frac{1}{\sqrt{2}}(\left<\phi\right| + \left<\psi\right|) undergoes an interaction with a second system (which is initially in \left<\alpha\right|) and ands up in an entangled state \frac{1}{\sqrt{2}}\left(\left\langle\phi\right| \otimes...

Hello all I am trying to measure material displacement using measured thermal data.7 While the specimen is heated up, I want to measure how much it changes its length at particular points. Is this possible? If you have any further questions or suggestions please do not hesitate to...

In the measurement ansatz below, must the state |O,ready> be orthogonal to |O,reads up> and |O,reads down>]? |+x> |O,ready> =1/(sqrt2)[|+z> + |-z>] |O,ready> (1) ---------→ 1/(sqrt2)[|+z> + |-z>] |O,ready> (2) --------→ 1/(sqrt2)[|+z>|O,reads up> + |-z>|O,reads...

Hi everyone, Can anyone tell me what information I'd need to calculate the maximum and minimum bounce angle of a tennis ball being fired at a tennis court? The ball is being fired at 30 m/s at an angle of 16° and the coefficient of restitution of the tennis ball is 0.759. What other...

At another thread under Special and General Relativity the following question was asked: "Why isn't stellar aberration considered to be a one way measurement of c? If the angle of aberration (θ-θ0) is -20.5 arc seconds and the Earth's orbital speed is 29.79 Kilometers/second normal to the...

Hello, as far I understand wavefunction collapse (or decoherence or whatever stops particles from acting as waves) is initiated through something referred to as a measurement. These measurements are thought of as interactions. Now the question I have is, why are some interactions measurements...

Why isn't Stellar aberation considered to be a one way measurement of c? if the angle of aberation (Theta) is 20.5 arcseconds and the Earth's orbital speed is 29.79 Kilometers/second normal to the arriving star light. The value of c should be: c= Vt/tan(Theta) = 29.79/9.94E-5 = 299737.98...

Hi all I have measured the resonance frequency of a resonator as a function of time by mean of a Laser-Doppler vibrometer and a frequency counter. In this measurement there are some fluctuations in the measured frequency as time goes by. My question is: How do I determine the resolution of...

A rectangular park has an area of five hectares (1 hectare = 10,000 meter square) The dimensions of the park on a map are 5 cm * 4 cm What is the scale of the map?

I have to measure the depth of the cavity in an object which is in the micrometer(10^-6 m) order. I'm given a laser, mirrors, neutral density filters, photodiode, and the object which is to be measured. Can anyone suggest scientific articles that are related to this problem provided with the...

Has anyone tried to apply the following regression equation appeared in the paper "Continuous measurement of systolic blood pressure using the PTT and other parameters" (Proceedings of the 2005 IEEE Engineering in Medicine and Biology 27th Annual Conference Shanghai, China, September 1-4, 2005)...

A Pitot-static tube connected to water manometer is used to measure the velocity of air. If the deflection between the two arms of the manometer is 12.4cm, determine the air velocity when the density of air is 1.25kgm-3 and the density of the water in the manometer is 1000kg/m3. I am not...

What is the difference between observation and measurement in reference to a quantum experiment?

Consider an experiment in which a closed box is set up with a system inside that is initialised at time t=0 with state psi(0). A measurement of quantity w of the box’s contents is made at time T, that is observed by scientist S1. There is another scientist S2 that can, by pressing a button...

I want to calculate the uncertainty in the period for a spring, when I have measured the extension of it under the influence of gravity. Call that x and say I got: x=0.10m ± 0.01 And we know that: T = 2∏√(x/g) Is it then correct to use the following formula for the uncertainty σT: σT =...

what is the difference between observation and measurement in reference to quantum mechanics?

A mercury thermometer with only the 0 degree Celsius and 100 degree Celsius markings on it was given to a student, and the student was asked to use it to estimate the temperature of a block of ice cream. I'm not sure, because the scale stops at 0 and mostly likely the temperature of ice...

I understand that an object can exist in many possible locations, and that when you're not looking, it is a wave. It's only when you look that it manifests itself into a particle. But Is that also dependent on the measurement of sound? Does an object materialize when you hear it, or feel a force...

I have laser drilled hole thin ceramic specimens and I am required to measure the diameter of the holes. Suggest me some methods.

For a pin photodiode, risetime=bandwidth/0.35 i get ~3ns for s5973 will it be affecting the measurement of 10ns laser pulse? How can i reduce the rise time?

In communicating with an astronaut on the moon, 3.8x10^8 m from earth, what is the minimum time delay in getting a response to a question? The answer in the book is given as 2.5 seconds.Have they simply used; ( (3.8x10^8) / c ) x 2

Transfer function of flow measurement system HELP! 1. I have attached the question, which is to derive the transfer function of a volumetric flow measurement system... 2. I know of the following relevant equations: F = Ma = MD^2.x Flow f = area x velocity and f through a...

Hi all I have assigned a task to measure distance at two points separated 200 mm apart on a cylinder having diameter about 300 mm dia. The distance from point and measuring point will be 150 mm and that of for second point will be 150.05mm.I have an idea of using two lasers mounted 200 mm...

How can velocity be measured in quantum mechanics since one can not measeure position without disturbing the particle?

Not sure if anyone will be able to answer these questions but it would be good if someone would give it a shot. A friend recently explained the measurement problem to me and i thought of a few questions which he was not able to answer. A) Do animals count as observers, and can they cause...

Just trying to follow Giancarlo Ghirardi reasoning in his book about differentiating between pure and mixture esembles. Is it possible to perform a measurement on an observable that, if it were in a superposition, a certain value would return?

Question - Regarding a cnc cmm controller, What is tunneling? How is this measured? What impact does the cmm structure have on this characteristic?

I am trying to design a system to measure the distance between two RF transceivers with as small of a resolution as possible. Time-of-flight measurement is nice and easy to do, but it has a poor resolution with low frequency timers. I am thinking of using a low-cost mcu that will probably have a...

I am currently using garder tubes to measure the viscosity of a material (mainly adhesives and some wax) in the process of manufacturing Newtonian as well as non-Newtonian materials. I am looking for an alternative method that is less qualatative in an attempt to decrease the defects per...

Hello Everyone, Here is my situation: I am using a laser to take distance (height) measurements on a variety of surface types (e.g. mirror, machined surface, plastic, etc.) and I would like to quantify the repeatability of the laser measurements on each surface type. Please note that I care...

Hallo alle users, as the title indicates, I have a question about measurement of thin film thickness by means of spectral reflectance. Given, the to be measured thin film has thickness less than 600 nm, but the measuring light has only wavelengh larger than 600 nm. Does it mean, that the...

I came up with something to think about while freezing in my room... How can one measure the temperature in a room withought traditional termometer. Alternative formulation of the question - is it posible to construct a termometer that would measure such temperatures as are measured in a...

This is not a question about relativity per se, but relates to it sufficiently I hope. Standard values for many scientific constants are defined, and ideally in the most universal way possible. For example, the standard length unit, a meter, is defined with respect to the distance light travels...

Hello all, In the following article I found through google, they explain how spin is measured: http://news.softpedia.com/news/Why-Is-Quantum-Mechanics-So-Weird-40009.shtml I understand how the Stern-Gerlach experiment works, but the article doesn't go into much detail about the next...

Why is the modern value of Hubble's constant so different from today's measured value? At first I thought it was because the Hubble constant is related to density via: ρ_c = 3H^2/(8*π*G) but in the past 2011 - 1921 = 90 years, I don't think the density could have changed that much since...

This is a question that's been in the back of my mind since I first learned quantum mechanics. There seems to me to be some tension between the postulates of unitary evolution and state reduction upon measurement: basically, any quantum system ought to evolve unitarily; so in principle, every...

I am building an iPhone app where the iPhone is just going to sit on my desk measuring the distance to Earth's core. I will build a calibration function into my app to reduce the variation in the estimate. How, then, should I go about calibrating it?

Hi there, Ok, so if you know the interactions, etc., you can calculate from time0 the probabilities for certain results at say time8. But say, however, we perform a measurement before time8. Will the original predictions for time8 still hold if a measurement is performed prior to that...