The particles tag has no wiki summary.
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1answer
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Uncertainty Principle on System of particles
I am new to Quantum Mechanics. I read the uncertainty principle - it says there are pairs of physical quantities which can't both be determined with certainty for a particle.
My question is does the ...
2
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1answer
59 views
Estimate the difference between two sets of atoms
I've been working on amorphous structures derived from a crystalline one (using MD) containing $N$ atoms. I want to prove that these structures are different and to quantify their "differentness". One ...
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0answers
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Acceleration by spherical particles (micron-scale) by an external force
I am looking for an expression for the velocity of a micron sized (1 - 10 micron diameter) sized particles under accelerating forces.
I have aerosols in mind.
This is what I have in mind
The ...
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2answers
512 views
Do particles and anti-particles attract each other?
Do particles and anti-particles attract each other?
From the very basic understanding that they are created out of nothing mutually and collide to annihilate each other seems to indicate this happens ...
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1answer
41 views
Convolving Parton Distribution Functions
I have the cross-sections as a function of $\sqrt{s}$ for a process with a $u$-quark and $u$-antiquark in the initial state (eg.: $u \bar{u} \to e^- e^+$). I have a standard parton distribution ...
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2answers
240 views
What if a faster-than-light particle is found?
What will be the consequence (severe ones) on laws of physics if a particle that travels faster than light is discovered?
I am looking for a more general answer so that a high school student would be ...
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0answers
76 views
Do particles travel backward and forward in time? [duplicate]
All these classical ideas are pointless and obsolete today, because in quantum mechanics, the particles are completely different objects, defined by quantum motion of fields, not by the location of ...
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2answers
127 views
Why is electron presented in books, pictures as a sphere?
Why is electron presented in books, pictures as a sphere, when in fact it's not?
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2answers
66 views
Does the unpredictability in the “micro world” means that everything is if we can look at it close enough imperfect?
Does the unpredictability in the "micro world" means that everything is if we can look at it close enough imperfect?
I mean, there is a saying "You will never stand in the same river again" or ...
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2answers
148 views
Why does the amplitude of a ripple tells us that it is a particle?
The quote below is from Matt Strassler's blog:
a particle is a ripple with many crests and troughs; its amplitude,
relative to its overall length, is what tells you that it is a single
...
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2answers
528 views
Frequency of an Electron
My question is very simple.
If frequency is defined as the cylces per unit time, Then what is meant by "Frequency of an Electron" ? If the rotation of electron around a nucleus is considered then, ...
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2answers
67 views
Can energy be defined as the most fundamental particle which exists in different forms as protons, electrons etc
What we see all the different forms of matter around is just a form of energy. Why can't this energy be the most fundamental particle. Given dust can turn into a star and then emit all sorts of ...
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1answer
127 views
Is the idea of dividing the universe into particles anything more than an untrue convenience? [closed]
In theory, we speak of a particle as having properties.
In reality, the measurement of any property is just an interaction between the target to be measured, and the measuring apparatus, where the ...
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2answers
80 views
Is there a map of the particles in outer space?
Since outer space is not quite a vacuum, and the distribution of various heavenly bodies is locally inhomogeneous, it seems reasonable to expect that the density and variety of particles ...
1
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1answer
71 views
Lifetimes of stable particles
What are possible lifetimes of up/down quarks, electronic/muonic/tau neutrinos, photon, gluon?
I understand they are said to be stable, but, as I saw on wikipedia, the lower bound for the "stable" ...
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2answers
942 views
Why can't massless particle exceed speed of light?
Why massless particle can't exceed speed of light?
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3answers
143 views
Do particle pairs avoid each other? Please end my musings
Can you explain what happens when a particle and its antiparticle are created. Do they whiz away from each other at the speed of light or what? I suppose that they don't because otherwise they would ...
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1answer
87 views
Can you tell if a particle is in superposition?
This may be an easy answer for anybody. Is it possible to detect if a particle A is still in a superposition via the sending a group of particles B through a box containing particle A?
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2answers
789 views
Speed of a particle in quantum mechanics: phase velocity vs. group velocity
Given that one usually defines two different velocities for a wave, these being the phase velocity and the group velocity, I was asking their meaning for the associated particle in quantum mechanics.
...
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2answers
112 views
How can Sub-Atomic Particles be Visualized?
Can you see or accurately visualise sub atomic particles or are they known only by maths and/or inference?
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1answer
110 views
Temporal part of Quantum Wavefunction
I was hoping that someone could give me the more fundamental reason that we take as the temporal part of a quantum wavefunction the function $e^{-i\omega t}$ and not $e^{+i\omega t}$? Clearly ...
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6answers
561 views
What is the meaning of the word “particle” in particle physics?
I want to use Matt Strassler's definition of the word "particle" as a specific example:
Matt Strassler writes:
(1) "...all the elementary “particles” (i.e. quanta) of nature are
quanta of waves ...
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3answers
2k views
How to deduce E=(3/2)kT?
It says in my course notes that a particle has so-called "kinetic energy"
$E=\frac{3}{2}kT=\frac{1}{2}mv^²$
Where does this formula come from? What is k?
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2answers
176 views
Particles vs Waves
As I remember long ago, in my physics classes, I always had a great trouble understanding the concept of waves. Our professor used to explain, as if everything in this world is made up of waves.
...
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3answers
92 views
Center Of Mass Troubles
I understand the concept of Center Of Mass(com), but I am having a difficult time interpreting the equation of the simplified case of one-dimension.
The book I am reading defines the position of the ...
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4answers
353 views
How can/does calculus describe the movement of a particle?
I was talking to Roger Penrose about calculus in the appendix in his book Cycles Of Time and he said I'd need a good understanding of calculus if I wanted to read his book in great depth. He said I ...
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1answer
253 views
Definition of elementary particle [duplicate]
Possible Duplicate:
Why are atoms particles?
According to wikipedia an elementary particle or fundamental particle is a particle not known to have substructure.
Moreover, I've learned ...
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1answer
90 views
$sss$ decay and violation of strangeness
Why can the hyperon $\Omega^{-}$ not decay by strong interaction? It seems that strangeness must be violated, but why is it the only way?
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1answer
139 views
Why doesn't my particle simulation end in a flat disc?
I've made a 3d particle simulator where particles are attracted to each other by the inverse of the square radius. The purpose of my experiment is to see if this alone would create a flat disk (like ...
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2answers
129 views
Understanding a Physics Paper on Quantum Teleportation of Continuous variables
The paper I am trying to understand is here:
http://pra.aps.org/abstract/PRA/v49/i2/p1473_1
The paper describes the quantum teleportation protocol in a general case with continuous dynamical ...
0
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1answer
90 views
Would synchronized dancing be a good way to describe entangled atoms to a laymen?
I was talking my professor about entanglement swapping between light and matter and it is briefly described here:
You start out with a crystal capable of doing parametric down conversion of incoming ...
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5answers
691 views
The observation of a non-SM resonance at 38 MeV
Was reported here. Of course if this is real it is very exciting. It leads me to the question: given that it took so long to find this resonance at a meager 38 MeV, is it possible that all SUSY ...
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1answer
188 views
What was the first discovery of the delta baryon $\Delta^{++}$?
The delta baryons (also called delta resonances) are a family of subatomic hadron particles which have the symbols $\Delta^{++}$, $\Delta^{+}$, $\Delta^{0}$, and $\Delta^{−}$ and electric charges +2, ...
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5answers
340 views
What needs to happen for one to ingest radioactive particles and how likely is this?
There are many stories about radioactivity and the relative danger of it in the news lately, but very little actual information. The radioactivity levels around Fukushima Daiichi are high, but seem ...
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6answers
550 views
Good book about elementary particles for high school students?
I need a good book about elementary particles. I am a high school student and don't want anything to technical. I read a brief history of time and the universe in a nutshell but i want something that ...
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2answers
138 views
Why are atoms particles?
The Oxford English Dictionary definition of particle is as follows:
"A component of the physical world smaller than the atom."
I read an article in NewScientist and it said
"...all particles from ...
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3answers
309 views
Can every particle be regarded as being a combination of Black holes and White holes?
Can the statement be regarded as true? That every particle, or element in the universe can be regarded as a combination of black hole and white hole in variable proportion.
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1answer
299 views
Why is it that protons and electrons have exactly the same but opposite charge? [duplicate]
Possible Duplicate:
Why do electron and proton have the same but opposite electric charge?
Doesn't it seem very curious that one is an elementary particle and the other a subatomic particle ...
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3answers
376 views
Existence of creation and annihilation operators
In a multiple particle Hilbert space (any space of any multi-particle system), is it sufficient to define creation and annihilation operators by their action (e.g. mapping an n-particle state to an ...
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2answers
493 views
Mechanism of Pair Production and Annihilation of Matter
Pair production is where an energetic photon on its interaction with strong electric field surrounding a nucleus produces electron-positron pair. Annihilation of matter is its converse where an ...
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1answer
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Is Joule heating only between charged particles?
The Wikipedia page for Joule heating explains
"It is now known that Joule heating is caused by interactions between the moving particles that form the current (usually, but not always, electrons) and ...
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5answers
144 views
Photoelectric effect without light rays
For electromagnetic waves we have the photon association, one imagines light as particles "flying around".
What is the analogy for a constant electrical field, one which doesn't change in time ...
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2answers
180 views
Very basic question on spin
Can anyone give a simple explanation for what the fractions and integers mean in particle physics when describing spin?
I've seen on another forum (the naked scientist) that it should not be thought ...
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2answers
263 views
Some very basic questions on the Higgs Boson
What exactly is a boson?
Is the Higgs boson the cause of gravity or a result of it? Does the collision of particles at the LHC create a gravity field or waves or somehow interact with the gravity ...
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1answer
70 views
Is particle number a problem for formulating statistical physics in a mathematically rigorous manner?
Quantities like the chemical potential can be expressed as something like
$$\mu=-T\left(\tfrac{\partial S}{\partial N}\right)_{E,V}.$$
Now the entropy is the log some volume, which depends on the ...
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3answers
318 views
What entities create a gravitational field?
It is well known that masses create a gravitational field. Photons are affected by gravitation, but do they generate a gravitational field as well? What about the other gauge bosons?
Do gravitons ...
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1answer
77 views
The Large Hadron Collider produce material residues?
In the LHC particles are accelerated until they collide, producing energy and this make new particles.
My question is what happened after this. What happened to new particles and to old particles ...
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3answers
891 views
Are elementary particles actually more elementary than quasiparticles?
Quarks and leptons are considered elementary particles, while phonons, holes, and solitons are quasiparticles.
In light of emergent phenomena, such as fractionally charged particles in fractional ...
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6answers
1k views
Massless charged particles
Are there any massless (zero invariant mass) particles carrying electric charge?
If not, why not? Do we expect to see any or are they a theoretical impossibility?
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2answers
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Higgs boson and quasiparticles
Do we know exactly the difference between particles and quasiparticles? Is Higgs boson a particle or a quasiparticle? I ask this because if I understood well, Higgs boson created by a spontaneaous ...
