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Questions tagged [experimental-physics]

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

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Status of experimental searches for tachyons?

Now that the dust has settled on the 2011 superluminal neutrino debacle at OPERA, I'm interested in understanding the current status of experimental searches for neutrinos. Although the OPERA claim ...
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685 views

What is the largest number of bosons placed in a BEC?

What is the record for the largest number of bosons placed in a Bose-Einstein condensate? What are the prospects for how high this might get in the future? EDIT: These guys reported 20 million ...
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174 views

Why do flux qubits have to be micrometer-sized?

Flux qubits are made using micrometer sized Josephson junctions. They exploit superconducting properties to create and interfere with the magnetic flux between them. My question is that I've seen ...
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161 views

Experimental Hopf fibrations

Recently I read a paper where the authors experimentally constructed a Hopf fibration - that is, they created a quantum system where the nematic vector field of the system had a non-zero Hopf ...
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148 views

Experimentally diminishing random errors for low wavelength UV observations

Part of the work that I do involves observations of solar low wavelength UV observations, specifically UV-B and UV-A II (up to 340nm). I have noticed that when I observe responses on a CCD or CMOS ...
7
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291 views

A theoretical model for evaporation occurring when wind is blowing over the surface of water

I've recently done an experiment in which I was studying the variation of the cooling rate of hot water in a draft (wind). The air was blow directly over the surface of the water (kept in a ...
7
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161 views

Large Hadron Collider 2015 upgrade, what may we discover?

I realise that the initial answer to my question that may come to mind is, "we don't know yet, obviously" But my question is hopefully not opinion based. For example, does this upgrade have a ...
7
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267 views

Does this method of predicting the ratio of translational diffusion coefficients for a sphere and a sheet, work?

Imagine that I have a spherical particle of molecular weight $M$, volume $V$, and some experimentally observed center-of-mobility translational diffusion coefficient $D_{sphere}$ in water. I take ...
6
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163 views

How to cleave a perovskite single-crystal in vacuum?

I am trying to cleave the lead-halide perovskite in vacuum to study its intrinsic electronic properties using photoelectron spectroscopy, since it is difficult to remove surface adsorption without ...
6
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125 views

Measuring the Dirac field

If the Dirac field $\psi(x)$ is to the electron as the Electromagnetic field is to the photon, why is it that we can measure the Electromagnetic field, whereas the Dirac field we cannot?
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74 views

Is it caustic reflection or hyperbolic projection?

actually last night I noticed a strange form of light rays on the wall of my room which were reflected off a CD. Here is its photo: Please let me know what is it exactly? A caustic projection or ...
5
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139 views

How can one confirm creation of magnetic graphene?

Recently my high school physics teacher contacted me looking for an expert to ask about this situation. I am paraphrasing his correspondence below: I just had a a student accidentally create ...
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280 views

Selecting an epi-illuminated objective for optical microscopy

I am currently trying to improve my silicon microphotography. To provide context: this is what I get with a 10x epi plan objective¹: This is what I get with 40x epi plan objectve with NA=0.65: I can ...
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501 views

What is the highest frequency directly detected?

The Feynman Lectures of Physics states: In fact, although we mentioned many frequencies, no phenomenon directly involving a frequency has yet been detected above approximately $10^{12}$ cycles per ...
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70 views

Experimental tests of Cluster Decmposition

How tight are experimental and astrophysical tests on whether Cluster Decomposition is satisfied at various space-like separations? Is there a review paper or a standard reference on the question? I ...
5
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291 views

Is there precision experimental evidence for Furry's theorem — that only even degree VEVs are non-zero?

Is there precision experimental evidence for or contradicting Furry's theorem -- that only even degree VEVs are non-zero, specifically for the EM field?
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35 views

Experimental challenges of increasing the size of a Bose-Einstein condensate

My question is partially inspired by this question. I know that BECs have been created whose side lengths are on the order of microns, while others have managed to make a side length of approximately $...
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48 views

Sterile (4th) neutrino and cosmological bound

Recent results by MicroBoone seems to give support to old LSND experiment in favor of a fourth neutrino (sterile). How does it fit with the current cosmological bound for neutrinos?
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127 views

Quantum (spin/thermal) Hall v.s. (Spin/Thermal) Quantum Hall effects

Are the following concepts defined correctly, as I understand: Quantum Hall effect is a quantum-mechanical version of the Hall effect, observed in two-dimensional electron systems subjected to low ...
4
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534 views

What is the third peak in the spectrum of Sodium-22?

I collected this spectrum from a sodium-22 sample in an instructional laboratory. The sample was set in front of a germanium detector which sends a signal into a pulse height analyzer and plots a ...
4
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190 views

How can I test whether my cloud chamber is supersaturated or not?

Me and my friend are building a diffusion cloud chamber for a school project. In stead of using dry ice or a peltier, we have used the phase changer of a freezer to cool our plate. We were able to ...
4
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0answers
233 views

On the right-angled fork track of alpha particles

In high school we were told that the idea "alpha particles are actually helium nuclei" came from observing the right-angled fork track, produced by placing an alpha source in a diffusion cloud chamber ...
4
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0answers
108 views

What experiments confirmed Poynting's Theorem?

Actually, I have two related questions. The fist is the above question. The second is, what experiments confirmed that $\varepsilon_0\left(\frac{E^2}{2} + c^2 \frac{B^2}{2}\right)$ is the ...
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86 views

How can I precisely measure the intensity of the Hydrogen Alpha (Balmer) line at low intensities?

I assume that I will need some kind of very precise filtering, but how is that accomplished? After that, photon counting at worst, but I am expecting millions of photons per second. The background is ...
4
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86 views

Experimentally realizable states for bosonic quantum fields

I would like to know which type of quantum states of a bosonic field, that have an explicit analytical expression as vectors/density matrices in a symmetric Fock space, can be prepared in an ...
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75 views

How can the effects of temperature be accounted for in-situ electrical resistance corrosion monitoring?

In reading the Berkeley Lab's article Rust Never Sleeps, where research is underway investigating the use of iron oxide rust as a photovoltaic, they state: Rust – iron oxide – is a poor conductor ...
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202 views

Baryonic density in collision experiments

Does anyone know any way of estimating the net baryon density in collision experiments, e.g. in LHC, RHIC, or the upcoming ones at GSI-FAIR? I have comes across many hand-waving arguments, sample - ...
4
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45 views

Experimental results regarding non-extensivity in small systems

From a statistical mechanics point of view, the extensivity of thermodynamics arises from the fact that we can neglect interaction terms in the Hamiltonian. This allows us to infer that when we put ...
4
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0answers
227 views

Did Penzias and Wilson need such a large horn antenna to discover the CMB?

Penzias and Wilson discovered the 2.7K Cosmic Microwave Background (CMB) Radiation using a 6 meter horn antenna, along with a cryogenic low-noise detector measuring at 4 GHz: http://en.wikipedia.org/...
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472 views

Toward the establishment of non-equilibrium (quasi-equilibrium) magnon BEC theory

In 2006, Demokritov et al have reported that they have achieved the observation of quasi-equilibrium magnon Bose-Einstein condensation (BEC) in YIG at finite (room) temperature by using the method ...
4
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0answers
770 views

How is the Geometric Phase measured in the experiment?

I had read some papers that have mentioned the geometric phase (Berry phase) can be used to detect the quantum phase transitions in a quantum many-body system. My question is: How is it measured in ...
4
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0answers
161 views

Remaining Potential Experimental Particle Physics Discoveries at the TeV Scale?

With the discovery of the Higgs Boson, some have been calling it the end of experimental particle physics for our generation, due to the fact that all of the particles predicted by the standard model ...
3
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33 views

Planck's constant calculated by photoelectric effect laboratory is off

I conducted an experiment today where I had to use a photocathode of unknown material (model: Daedalon Corporation Photoelectric Effect EP-05) and study the photoelectric (PE) effect to make a ...
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52 views

Do a floor tile or dry sand conduct electricity

If you touch an electric wire while standing on a ground made of soil or floor tile, you will get electrocuted. So, electricity passes through it. Right? Shall I conduct an experiment by passing ...
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79 views

How did we first discover oxygen exists as $\rm O_2$ and not just $\rm O$?

How did we first discover oxygen exists as $\rm O_2$ and not just $\rm O$ ? (similarly hydrogen as $\rm H_2$ and not $\rm H$) I vaguely remember knowing a story about how the chemical formula of ...
3
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0answers
65 views

What are common methods to remove discretization on experimental measures?

I have some experimental data, and since the measurements are digital, the data is discretized/quantized/rounded/truncated. I need to know if there are general methods, or common methods, to "smooth" ...
3
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133 views

Books on the experimental evidence for Special Relativity?

Lately I've been interested in investigating the more intricate parts of special relativity beyond what is readily apparent on wikipedia or physics 101 videos. So, besides mathematical treatments, I ...
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66 views

Is there a way to speed up Peltier cooling?

Speed up in sort of like, once you connect the powers, you don't have to wait long for the Peltier element to cool down to desired temperature. Is there a way to fix this, perhaps use two or three ...
3
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0answers
118 views

What do I measure with power meter?

I modulate directly a laser diode by setting the pump current periodically from 0 A to $I_{on}$ A. I do it for different duty cycles and different frequencies. But I need to keep my average power of ...
3
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0answers
72 views

Why would oscillation of a gas column inhibit rather than promote mixing?

Many years ago I helped to support an experiment conducted in Japan which investigated the effects of high frequency oscillation ventilation (HFOV) on the mixing and distribution of gas into the lungs....
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69 views

To what degree the probabilistic nature of quantum mechanics is tested?

I am not sure the question is well posed, what I mean is sort of an experiment in which one extracts some random, say, uniform distribution out of a quantum processes, and tests to what degree that ...
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95 views

How is Spin experimentally determined?

I know what spin is and how theories determine it for particles. What I don't understand yet, is how people, through experiments and data analysis or whatever, reach to confirm/say that the $X$ ...
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0answers
71 views

How to determine if a superconductor is type I or II?

What experimental measurements are available to determine whether a superconducting single crystal/polycrystalline sample is type I or II? I.e. BCS vs non-BCS? An answer would mention the ...
3
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0answers
58 views

How “steady” are screw threads?

I have a setup whereby two stainless steel end caps screw into a similar tube about 100mm in length and 25mm internal diameter. Thread is fairly standard, and is finger tight. The question is: ...
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0answers
133 views

Are Cosmic Microwave Background (CMB) photons entangled?

Suppose we'd like to know whether two cosmic microwave background photons emitted from different parts of the sky have any quantum correlation with each other. We could measure polarization of two ...
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0answers
94 views

Energy dependence of integrating dosimeters

The graph shows the relative response of a dosimeter at different energies, normalized to 1.25 MeV Co-60 gamma rays. Curve A is the graph of the equation $$ \frac{\bigg(\frac{r}{X}\bigg)_\bar{E}}{\...
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45 views

What material could be used to study magnetic phase transitions in a college laboratory exercise?

I am working to develop a simple laboratory exercise in solid state physics to be conducted by fourth year students of physics. The idea of the exercise is for the student to get some experience in ...
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139 views

How to distinguish Shake-Up Satellites from Plasmons?

I am studying XPS spectra (X-ray Photoelectron Spectroscopy) at the moment. In XPS, different processes can influence the final state energy of detected electrons. One of these processes is the ...
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How could we find preons?

If I understand correctly, scientists were able to find strong evidence for the existence of quarks by using deep inelastic scattering. If quarks (hypothetically) are composed of preons, could we use ...
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479 views

How can systematic errors be calculated?

Usually, it is said that systematic errors can not be handled in a well-defined way, unlike statistical errors. My questions: How can systematical errors be calculated for any experimental device ...