for questions about design, process, data, or analysis of experiments and observations.

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2answers
219 views

Has magnetism been experimentally demonstrated at the quantum level?

I've learned that magnetic fields are generated by electric currents, and that electric current is the motion of electrons and stuff like that. Many textbooks also talk about "point charges" and have ...
1
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1answer
30 views

What is the easiest way to demonstrate low magnetic flux NMR on the bench?

I'm trying to build my own low fux density bench NMR set-up, and am well-versed in electronics. Continuous Wave is supposed to be the easiest. I see commercial instruments that stimulate elements in ...
41
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6answers
7k views

What technology can result from such expensive experiment as undertaken in CERN?

I wonder what technology can be obtained from such very expensive experiments/institutes as e.g. undertaken in CERN? I understand that e.g. the discovery of the Higgs Boson confirms our understanding ...
2
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1answer
78 views

References on experimental realization of quantum one-dimensional infinite-well model

Can someone point me to the examples, or references, of experimental realization of the quantum one-dimensional infinite-well model? [EDIT] The motivation of this question is the curiosity - though ...
1
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1answer
57 views

Error calculation for experimental data

I have the list of experimental values: $$\{w_i \pm \Delta w_i\},$$ where $w_j$ is a mean value and $\Delta w_i$ is an error. I want to calculate the second list $\{a_i \pm \Delta a_i\}$ according to ...
2
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2answers
68 views

Where can I find the datasets from LHC?

I know that most of the datasets from ATLAS or other particle physics experiments are terabytes, but I was just curious is there any place where one can find them to download? And one more question, ...
1
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0answers
55 views

Flow from the bottle

I made some calculations about flow from the bottle, but problems occured when the experimental data came back. Need to refine calculations, but problems occur when trying to link the angle to the ...
28
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6answers
2k views

How to determine your position underground?

Crossed my mind after random rant on wikipedia that lead me to articles about chronometers and measuring position. Let's assume I were trapped in the underground laboratory with lots of equipment ...
1
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1answer
31 views

In real laser applications, how big is the complex parameter (i.e. <n>) of the corresponding coherent state of the field?

In quantum optics, the output from a laser is modelled using a coherent state; what are some orders-of-magnitude for the complex parameter (usually denoted $\alpha$) of the coherent state ...
21
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2answers
2k views

What exactly do we see on the famous neutrino image of the sun?

An answer to the question If we could build a neutrino telescope, what would we see? contains a link to a neutrino image of the sun by the Super-Kamiokande neutrino detector. There it says that ...
1
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1answer
58 views

How do you actually cool the atoms to create the Bose-Einstein Condensate?

What is the actual way you cool atoms to a low enough temperature that you can observe their quantum behavior at a macroscopic level, like in the Bose-Einstein Condensate? ...
1
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1answer
52 views

Thought Experiment: Force on magnets in a Stern Gerlach Experiment

Background: In the SG experiment, an inhomogenous magnetic field affects a force on particles passing between two magnets. "Measurement" takes place when a screen is placed on one end, blocking one ...
-3
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1answer
139 views

About the Large Hadron Collider [closed]

I think Physics is fascinating , especially those really clever experiments one can do that demonstrate some important principle and probably don't cost a lot of money to make. Also the Thought ...
7
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1answer
97 views

Why Are Normal Shock Waves Unstable in a Converging Channel?

While learning about shock waves in an introductory Gas Dynamics course, it was revealed that normal shocks are unstable if formed in a converging channel. Even if the local conditions ostensibly ...
0
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0answers
25 views

Inclusive and exclusive searches [duplicate]

Please, I would like to know what means inclusive and exclusive searches in High Energy Physics. Thanks in advance. Fábio.
1
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1answer
60 views

How to measure the pressure on the walls of a potential box by a particle inside?

Consider a quantum particle inside a 3D potential box. One can compute the pressure that it exerts on the walls, it's OK. But what puzzles me is how do we actually measure such a pressure? If we take ...
1
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1answer
44 views

Data/signal from a black hole to observe a singularity

I wonder if a situation is possible where, we measure some signal/property concerning a black hole. Supposing the measurement we make with some telescope, gets us the Fourier transform coefficients of ...
4
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3answers
238 views

What factors determine whether wind resistance will have an important effect?

What factors determine whether or not wind resistance will have an important effect on the trajectory of a projectile?
2
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2answers
64 views

How do we observe the expansion of the universe?

This is my first question. So I was reading about expansion of the universe and from what I've seen, the only way that we know that universe is expanding is by measuring redshift. Also, here it says ...
2
votes
1answer
50 views

Magnet spinning between two other magnets

Suppose, we have two magnets, MA, MB, and we have a third magnet MC in between the two magnets. Each magnets' north pole faces the other magnets south pole, and the magnets are placed horizontally ...
0
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1answer
26 views

Can Allan variance be generalized such that the “Oscillator model” is not presumed?

The definition of Allan variance, $\sigma^2[ \tau ]$, which relates to "stability of clocks" is described on the Wikipedia page as being derived in terms of an "Oscillator model": "The oscillator ...
1
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0answers
26 views

Nonlocal interaction effects on bose-einstein condensates

I'm studying an interacting bose-einstein condensate using the energy functional proposed in this paper K. Huang, C.N. Yang, Phys. Rev. 105 $$ E\left[\phi\right] = \int d^3\vec{r} ...
1
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0answers
14 views

How to express Allan variance without neglecting clock drift

Allan variance, $\sigma^2[ \tau ]$, or its square root (Allan deviation, $\sigma[ \tau ]$) is a quantity (as function of parameter $\tau$) which is said to be a measure of (or related to) "stability ...
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0answers
32 views

Bell State Measurement From Parametric Down Conversion Source

My question is about whether or not there exists any scheme to distinguish between symmetric and antisymmetric Bell states from entangled pair of down converted photons. State of Down Converted ...
1
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0answers
35 views

How many measurements of a physical quantity should you do to get a representative value / distribution? [closed]

When we measure a physical quantity multiple times, we can calculate several values which should help us understand the whole measurement better: Standard deviation, variance, median, average, and so ...
0
votes
2answers
128 views

Inductor Charging and Discharging

Why does the inductor discharges in the same path ( same direction of current ) as that of its charging unlike a capacitor which discharges in the direction opposite to its charging(current direction ...
0
votes
2answers
60 views

What is the relationship between radation intensity and count rate?

If you know that the radioactive source is, for example, Cesium-137, is it possible to extrapolate a relationship between the count rate and radiation intensity? If it is not possible, what is the ...
15
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6answers
2k views

Why should any physicist know, to some degree, experimental physics?

I've been trying to design a list with reasons why a proper theoretical physicist should understand the methods and the difficulty of doing experimental physics. So far I've only thought of two ...
0
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0answers
20 views

QED Laser Reflection Mirror Expirment

Feynman in his famous lectures in NZ, talked about an experiment with a reflection of a light from a "back" mirror with stripes on it I tried to find a video of such an experiment, but with no ...
1
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3answers
71 views

Experiment demonstrating interference patterns of neutrons

The question is about experiments (and references) that demonstrate interference patterns of neutral (chargless) particles (fermions), especially neutrons. Like double-slit experiments for neutrons ...
0
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1answer
86 views

Circuit breaker Trips during thunderstorm

The circuit breaker at the electrical mains trips at home when there is a thunderstorm outside. Why does this occur?
5
votes
1answer
82 views

How did Fizeau make his famous speed-of-light experiment?

I heard once in a TED talk how Fizeau measured the speed of light in the 19th century. Here is the link https://www.youtube.com/watch?v=F8UFGu2M2gM You can read about it here in Wikipedia: ...
4
votes
1answer
61 views

What does a MEMS gyro measure during off-axis rotations?

I've been working with MEMS gyroscopes in hobbyist projects for years—but it's recently come to my attention that I don't have any principled understanding of what rotation rate measurements ...
2
votes
0answers
23 views

How to check the ohmic contact to the film?

I have a thin semiconductor film deposited on an isolating substrate. I would like to check different metals to find out do they form the ohmic contact or Schottky barrier. What is the best way to do ...
28
votes
4answers
4k views

Has gravity ever been experimentally measured between two atoms?

Has there been any experiments, or are there any references, demonstrating gravity between atoms? If so, what are the key experiments/papers? Or if not, what is the smallest thing that has actually ...
-1
votes
1answer
67 views

Can you get Born probabilities that are irrational from an experiment?

Is it possible to design an experiment getting irrational number predictions (in practice, you can't actually measure infinite numbers of decimal points, obviously) for Born probabilities? If you ...
9
votes
3answers
145 views

What are the main algorithms the LHC particle detectors use to reconstruct decay pathways?

I am just starting to look into how we understand the data from particle collisions. My question is, what are the algorithms or ways that these detectors interpret the data? Are there standard ...
5
votes
4answers
142 views

Can “vacuum be brought” from outer space?

Instead of creating vacuum in chambers on earth, why can't vacuum be brought from outer space in chambers? Outer space pressure ranges from $10^{-6}$torr to $10^{-17}$torr very very low. Is it ...
1
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0answers
37 views

Is spin an observable quantity for fundamental particles? [duplicate]

How we know that the spin of fundamental particles? For example spin-0, 1/2, 1,2.. What is the experimental facts about spin?
0
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0answers
21 views

Dispersing ultrasound in a tube - patters

I am looking for patterns to efficiently disperse reflected ultrasound in the range of wavelengths 1mm to 4mm within the interior of a narrow tube (I do not want wall reflections). For various reasons ...
2
votes
4answers
132 views

What experiment would disprove Friedmann model of cosmology?

What experiment would disprove Friedmann model of cosmology? As a layman, I have read a lot of articles and threads in specialized forums. I am probably wrong, but I developed an impression that that ...
1
vote
2answers
84 views

Experimental Verification of No Special Frames of Reference

Certainly, there have been numerous tests of both Special Relativity and General Relativity. Given all the phenomena and behavior stipulated by Relativity, one could perhaps divide these phenomena ...
1
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0answers
29 views

About Paschos-Wolfenstein relation (Weinberg angle measuring)

There is Paschos-Wolfenstein relation: $$ \tag 1 \frac{\sigma^{NC}_{\nu_{\mu}} - \sigma^{NC}_{\bar{\nu}_{\mu}}}{\sigma^{CC}_{\nu_{\mu}} - \sigma^{CC}_{\bar{\nu}_{\mu}}} = \frac{1}{2} - ...
5
votes
3answers
116 views

Normal modes of the 2D double pendulum

I'm performing an experiment with a 2D double pendulum, and in part of it I want to investigate the normal modes of the double pendulum, where the pendula are not of equal length or of equal mass. My ...
1
vote
2answers
83 views

Airplane on a treadmill [duplicate]

I've heard conflicting answers, and would like to see the record set straight: An jet/propeller airplane is traveling on a giant treadmill at takeoff speed. Will the plane takeoff, or will it remain ...
0
votes
2answers
37 views

Peak at zero in one device and not the other

I was wondering if anyone could shed some light on this problem. I have placed two accelerometers on an animal one sampling at 50 Hz the other at 100 Hz. They were placed in the same position. I then ...
23
votes
5answers
7k views

Is this kids experiment a legitimate way to show that air has mass?

Consider the experiment in this link. The experiment includes using a ruler as a lever, with an inflated balloon on one side and a balloon which is not inflated on the other. The aim of the ...
5
votes
1answer
68 views

Has anyone experimentally shown the quantized thermal hall conductivity in Quantum Hall systems?

For background: In a $D=2+1$ state with edge modes described by a chiral $( c_L \neq c_R )$ CFT there is a predicted thermal Hall conductance associated with the gravitational anomaly at the edge. ...
14
votes
2answers
1k views

Evidence of why the Standard Model is a successful theory of particle physics

When discussing physics with laypersons, I'm often in the situation where I have to explain what the Standard Model is, and why it's a successful theory of particle physics. To help in such ...
5
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2answers
374 views

Why do plastic bags make less noise when immersed in water and crushed?

When a plastic bag is crushed in air it makes noise. But when immersed in water and then crushed we hear very little noise. Why is it so? Even if I go inside water, I do not hear the noise the same ...