# Tag Info

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Yes, the interference pattern will occur, although you'll have to wait a while to be able to see it. As long as the average arrival time between photons is markedly greater than the travel time from slit to detector, the actual rates don't matter - each photon interacts with the slits by itself. This URL shows such an experiment, in which a laser beam was ...

8

If there are enough data and the prior is not completely unreasonable, the frequentist and the Bayesian approach give essentially the same answer. This is related to the central limit theorem. If data are fairly scarce, the two approaches may differ a lot. In this case the Bayesian approach is far preferable but only if the prior reflects true prior ...

4

Here is an experiment trying to limit dark energy theories which predict detectable interactions with matter: If dark energy --- which drives the accelerated expansion of the universe --- consists of a light scalar field, it might be detectable as a "fifth force" between normal-matter objects, in potential conflict with precision tests of gravity. ...

4

I'd like to expand my earlier comment into a little essay on the severe practical difficulties in performing the suggested experiment. I'm going to start my asserting that we don't care if the experiment is a "two-slit" per se. It is sufficient that it is a diffractive scattering experiment of some kind. However, we do care about having spacial ...

4

The interference pattern comes from the calculated wavefunction phase difference at a specific position of the detector. Every interaction of a particle along its paths (whether they are real/collapsed or virtual/calculated) would randomly bring a phase difference to the calculated wavefunction, therefore its coherence would be quickly destroyed as the ...

3

How do we measure the position of an electron with a light source? Experiments with elementary particles are mostly scattering experiments. One needs the source of the particles and a detector that can identify particles. In this figure we see electrons one by one passing the slits and leaving a point (x,y) on a screen sensitive to electrons (deposition ...

3

Yes,you will see the interference pattern,time doesnt matter if the conditions are same. If you send one electron it will hit particular point on the screen,you cannot predict where it will hit,but ofcourse you can predict the probability of hitting a particular point. after many days,most of the electrons will hit the most probable regions and few hit ...

3

My intuition is that creating H gas in the lab is very hard (as opposed to H$_2$ gas). Not at all; any sufficiently hot hydrogen plasma will have a greater abundance of H than of H$_2$. To see why this is so, it is sufficient to consider the energies of the molecular bond relative to the ionization energy. The energy of the bond in a hydrogen molecule ...

3

Time taken to cover a distance L by an object moving at a speed V is given by $$t = \frac{L}{V}$$ where t is the time taken. Therefore, the size of the object does not matter at all. Whatever be the size of two objects; if they have the same speed, they will cover the same distance in a given time. But, usually objects with a better aerodynamic design ...

2

Please correct me if I'm wrong, but I thought that no one had been able to show how General Relativity (GR) emerged from LQG in the semi classical limit ? In this context, it may make sense to ask for experimental manifestations but to me it would seem more important to make sure first that LQG gives in some limit a classical theory of gravitation before ...

2

So, "phenomenological quantum gravity" is the particular field where we consider experimental tests of quantum gravity (with the hopes of winnowing the 3 dozen competing theories down to a handfull). To the best of my knowledge, Giovanni Amelino-Camelia pioneered the field (c.f., Amelino-Camelia's review article). At any rate, when focusing on loop quantum ...

2

Within the standard model alone, all these parameters are independent, and to those you can add the masses and mixing angles of the neutrinos. Possible additional symmetries beyond the standard model suggest some relations between the gauge couplings, since renormalization group analyses based on these symmetries lead to unification of these couplings at ...

2

I am sorry to disappoint you, but there is no such formula that you can just apply. This is because it strongly depends on how and under what exact conditions and with wwhich tools you did the experiment. Think of this: If every methanol molecule reacts (burns) at once all at the same time, then the exact same amount of energy is spent, but it went really ...

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As noted in the comments, weight must be evenly distributed or the washing machine will spin off center and shut down. Clothes are a lot of small pieces. When spinning starts, they fly to the outside. Usually they are uniformly distributed. A duvet is a single large piece. It is easy for it to be off center. For example, if you wrap it around the ...

2

Experiments with trapped ions generally use fluorescence for detecting the ions. This means that they use a strongish pump to take the ion from its ground state to a dipole-allowed excited state and wait for the ion to decay by emitting a photon in a random direction, and then re-run the cycle over and over. This means that each ion essentially emits one ...

1

This may be cheating - but ozone is generated by the interaction of the high voltage discharges and the oxygen in the air. Why not flush the system with nitrogen - if there is no oxygen, no ozone will be produced. And a few mL per minute is not a lot of nitrogen. A 70 L bottle of nitrogen at 200 bar should expand into 14000 liter of nitrogen at STP - at 3 ...

1

The absolute cheapest thing could be to wire a variable resistor in series to try to get the discharge voltage down: it's possible that you could reach a regime where you're only ionizing some of the gases in the air, without melting the resistor. Since ozone's "badness" comes from being hyper-reactive you might be able to remove it chemically by putting ...

1

There are lots of tried and tested methods for visualising flows, for example mica or aluminium flakes though these tend to settle fairly quickly. In days gone by I used zirconium phosphate that had been delaminated by titrating with tetramethyl ammonia. This gives very thin flakes that are stable to sedimentation for a day or so, though you have to prepare ...

1

It is possible to measure wavelengths of light to many decimal places. When you see accurate determinations of atomic energy levels, they were done spectroscopically, looking at absorption or, more commonly, atomic fluorescence. Since $E=hc/\lambda$, one can accurately convert between wavelength and energy. When excited, atoms emit many wavelengths of ...

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Soft x-ray optics typically uses grazing reflections on suitable mirror materials and gratings (e.g. Pt coated optics) or crystals and the detection can be done with scintillators using CCDs or PMTs. Commercially available instruments have approx. 0.2eV resolution (2000 lines) while research grade instruments can achieve much higher resolutions e.g. 30000 ...

1

the reason for enclosing the gold leaf in a container is simply that gold leaf is exceedingly delicate. The container protects the gold leaf from air currents that would otherwise move the gold leaves or even tear them. The exact nature of the container isn't important, and any container would work, though obviously we need it to be transparent so we can ...

1

To quote from Will's book (Theory and Experiment in Gravitational Physics, Rev. Ed., Cambridge, 1993), "[...] in almost all experiments discussed in this book, the observable effects of torsion are negligible". Will then mentions a counterexample (Ni, Phys. Rev. D 19, 2260 (1979)), but that example is a specific theory in which torsion propagates and ...

1

Imagine that the sended electron interacts with the surface electrons from the slits edges. Together they form a quantized electric field. This field is not static in the sence that the position of the incoming electron is slightly different and the surface electrons are not standing still. The incoming electrons get deflected from the surface electrons (or ...

1

There is one, very limited and very deceptive, experimental case in which a large object can "cover more distance" than a smaller object at the same speed: Say you have two small cannons in a gymnasium and are going to launch two projectiles - a round cannonball and a long pole - to the opposite wall. The gymnasium wall is 100ft from the back of each ...

1

As boyfarrell pointed out, the IR peak that you observe is due to second order reflection from the diffraction grating of the spectrometer. Strong spectral lines are often seen in the second order (with the advantage of better resolution). You can easily verify it by inserting a long-pass filter that blocks 370 nm (some orange glass or even sunglasses) ...

1

Some background. You want to detect the image of an object. First, either 1) you illuminate it with some light source [a lamp, the sun] or 2) the object itself radiates light out [a star, a fluorescent sample]. Imagine to divide the object in many small parts (voxels): to reconstruct the image of the object, you need to detect independently the light coming ...

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It has been pointed out that this cannot simply be done by examining the mass distribution (first and second moment of mass). But there is a way to "look inside" most common objects: Take a CT scan. Not sure if you consider that "typical" lab equipment - but it's equipment I have in my lab... Of course depending on the size of the object and the material ...

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