Questions tagged [experimental-physics]

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

601 questions with no upvoted or accepted answers
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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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743 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 ...
14
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2answers
352 views

Can the question of a gravitationally accelerated charge radiation be tested experimentally?

I know that the question of radiation from a gravitationally accelerated charge has been discussed extensively at Does a charged particle accelerating in a gravitational field radiate?. Yet the ...
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178 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 ...
12
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1answer
376 views

What optical resonator configuration produces the most output power for a laser?

For various reasons, I have a HeNe laser setup with two external spherical mirrors that I can position and align at will. I've looked around at various sources, which all make mention of which optical ...
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162 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 ...
10
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1answer
172 views

How does the “Look Else Where Effect” affect the chances of detecting a false diphoton excess at the LHC?

Back in December 2015, there was found a 750 GeV diphoton excess in both CMS and ATLAS at the same location with a significance well above $3\sigma$; a 0.13% chance of being false. However, there ...
9
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1answer
186 views

“Modern Presentation” of Observations on Phase Transitions

In the introduction of Introduction to QFT by Peskin and Schroeder, the authors write "we do not discuss the beautiful and varied experiments on phase transitions that led to the confirmation of field ...
9
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1answer
175 views

Detailed form of light waves in vacuum and how to test it experimentally?

Consider a light wave in vacuum. Do the $\vec{B}$ and $\vec{E}$ fields have to be orthogonal to each other? Since you can add constants to a solution to Maxwell's equation it doesn't seem neccesary ...
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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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160 views

Experimental time-series for quantum particle-in-a-box or simple harmonic oscillator?

I would like to see experimental results for repeated measurement of a single-particle, quantum system that is approximately either particle-in-a-box or simple harmonic oscillator. If particle-in-a-...
7
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307 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 ...
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162 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 ...
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269 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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0answers
200 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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134 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?
6
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1answer
145 views

How did the first image of a black hole test the general relativity?

Recently, the event horizon of the black hole at the center of M87 was directly imaged by the EHT. My college professor said this could serve as another test of the accuracy of general relativity. ...
5
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77 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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140 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 ...
5
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299 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 ...
5
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522 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 ...
5
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71 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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298 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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115 views

How do measurements of $G$ account for variations in the local gravitational field?

One of the notable discrepancies of modern physics is the current disagreement of measurements of the gravitational constant $G$, well beyond reported uncertainties (and agreeing only to about 1 part ...
4
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1answer
94 views

Detecting the electroweak unification in data of quark gluon plasma

Electroweak unification is discussed in the Big Bang model and variant proposals, and there is a transition at energies of 100 GeV where the EW symmetry is unbroken and a quark gluon plasma phase ...
4
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46 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?
4
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148 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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553 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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216 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
256 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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110 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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87 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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77 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 ...
4
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204 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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47 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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235 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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475 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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800 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 ...
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165 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 ...
4
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1answer
221 views

Quantum fluctuations in a classical domain?

"In the presence of chaos, even small fluctuations (including quantum fluctuations) can be amplified to produce large uncertainties in later behavior"(http://arxiv.org/pdf/gr-qc/9210010v2.pdf) Is there ...
3
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41 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 ...
3
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0answers
46 views

Why does the iron and gallium alloy called Galfenol generate electricity under impact forces?

The scientists in the experiment took a rod made of galfenol - which is iron doped with gallium - placed it under high pressure impact forces on both ends while under a magnetic field and discovered ...
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112 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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82 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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2answers
551 views

What's a good book on experimental methods for physics?

I have read many books which can guide one in becoming a better theoretician but I haven't come across many books that help one become a better experimental physicist. For some reason the history of ...
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67 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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0answers
136 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 ...
3
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1answer
149 views

Does a homemade evacuated tube produce X rays?

Recently, I've bought a tiny USB powered spark gap bipolar Tesla coil (rated at 15 mA and (35-50)kV). I am a pretty interested in spectroscopy, so I played around with the tesla coil and a couple of ...