An interpretation is an assignment of meaning to the symbols of a formal language. Many formal languages used in mathematics, logic, and theoretical computer science are defined in solely syntactic terms, and as such do not have any meaning until they are given some interpretation. The general study of interpretations of formal languages is called formal semantics.
The most commonly studied formal logics are propositional logic, predicate logic and their modal analogs, and for these there are standard ways of presenting an interpretation. In these contexts an interpretation is a function that provides the extension of symbols and strings of symbols of an object language. For example, an interpretation function could take the predicate T (for "tall") and assign it the extension {a} (for "Abraham Lincoln"). Note that all our interpretation does is assign the extension {a} to the non-logical constant T, and does not make a claim about whether T is to stand for tall and 'a' for Abraham Lincoln. Nor does logical interpretation have anything to say about logical connectives like 'and', 'or' and 'not'. Though we may take these symbols to stand for certain things or concepts, this is not determined by the interpretation function.
An interpretation often (but not always) provides a way to determine the truth values of sentences in a language. If a given interpretation assigns the value True to a sentence or theory, the interpretation is called a model of that sentence or theory.
For 2 years now I have been reading posts at my university student forums about how the Copenhagen Interpretation is redundant because ensemble physics is the equivalence of CI and it is ensemble that is used in day to day physics. While I sympathize with applied physics and engineering I just...
I would like to hear comments about interpretation of photon interference in context with Pfleegor-Mandel experiment "Interference of Independent Photon Beams". There is a blog post about this experiment: http://scienceblogs.com/principles/2010/11/19/interference-of-independent-ph/. Original...
Homework Statement
Compare the cyclotron resonance signal from Silicon in figure 28.9b (in Ashcroft and Mermin) with the geometry of the conduction band ellipsoids shown in figure 28.5, and explain why there are only two electron peaks although there are six pockets of electrons. Homework...
Dear Forum :
I'm reading a cross section data of 20MeV proton + 16O reaction from ICRU 63.
( as attachment and link http://ppt.cc/qf-9 )
The total cross setion of (p,n) reaction is 4.372mb
However, the cross section of emitting neutron of energy between 0 to 1.5MeV is 0.91 mb / MeV.
The...
Hi PF
I am reading this paper and this one.
Zurek insists on the fact that pointer states emerge when the same information is imprinted in a huge number of disjoint subsystems of the environment.
Many observers can read those informations and agree with the others.
He never tells what this...
Hello,
We were introduced to Laplace transforms in my ODE class a few days ago, so naturally I went online to try to figure out what this transform actually is, rather than being satisfied with being able to compute simple Laplace transforms.
The Wikipedia page for the transform says it...
Let:
gn(x) = 1 in [1/4 - 1/n2 to 1/4 + 1/ n2) for n = odd
1 in [3/4-1/n2 to 3/4 + 1/n2) for n = even
0 elsewhere
Show the function converges in the L2 sense but not pointwise.
My issue is in how I should use the definition of...
The Gibbs paradox in statistical mechanics is usually resolved by saying that particles do not have distinct trajectories, and so are truly identical.
For example, http://ocw.mit.edu/courses/physics/8-333-statistical-mechanics-i-statistical-mechanics-of-particles-fall-2007/lecture-notes/...
For those interested in this stuff, what is your opinion of this less well-known Vaxjo interpretation:
Vaxjo Interpretation of Wave Function: 2012
http://arxiv.org/pdf/1210.2390.pdf
"Einsteins Dream”-Quantum Mechanics as Theory of Classical Random Fields
http://arxiv.org/pdf/1204.5172.pdf...
An article in Nature reports a negative result from the LUX experiment's attempt to directly detect dark matter:
http://www.nature.com/news/no-sign-of-dark-matter-in-underground-experiment-1.14057
Can anyone give some context? How does its sensitivity compare with that of previous...
Is this a proper summary of a minimal-no-collapse interpretation? (I like to call it the fuzzy world interpretation, but I suppose I'm the only one)
When objects entangle, it constrains their degrees of freedom. As they entangle with more and more objects, their degrees of freedom are...
Which of the following is true if the mass is at rest at t=0 ?
A. Velocity of the mass is decreasing btwn 10 and 20 seconds.
B. The accel. of the mass is constant between 0 and 10 seconds
C. At 40 seconds the mass is stationary.
D. The distance trsveled by the mass bten 0 and 10 seconds is...
I've been reading through the posts on this forum that deal with the photoelectric effect as evidence for the quantization of the EM field. In all of the introductory texts I've read, the cut off frequency and the dependence of the photoelectron energy on the frequency of the light are...
Homework Statement
(a) Starting from a point on the equator of a sphere of radius R, a particle travels through an angle α eastward and then through an angle β along a great circle toward the north pole. If the initial position is taken to correspond to x = R, y = 0, z = 0, show that its...
Consider we have a \Lambda type three level system, the one upper level is denoted by 3, and the two lower levels are denoted by 1 and 2. Assuming that the transitions between 1\leftrightarrow3 and 2\leftrightarrow3 are dipole alowed, while the transition between two lower states 1 and 2 is...
I am looking for a counting interpretation to make the following identity evident:
\sum_{k=0}^{n-j}(-1)^k\binom{j-1+k}{j-1}\binom{n}{j+k} = 1
The form of it looks like inclusion-exclusion. The sum is 1, more or less independent of j. So that makes me think it would be something like "how...
Hello everyone,
I'm a doctoral student of particle physics in ETH Zurich, and have a question in fundamental QM.
I remember a friend telling me that the professor that taught him Quantum Mechanics in ETH Zurich did not believe in the Copenhagen interpretation, and thus taught the class...
Hi friends, i have i request for you. For my statics exam i need integrals and i found this page in russian, and can not find rest or even know how it's called because when i translate title i don't get any results. Can you please help me and tell me where can i find the rest...
I had trouble understanding this and had brought it up before but I thought I'd start a new thread on it, in case anyone has any further insights. In the original Leifer summary discussing the implications of PBR theorem on the various QM interpretations, Leifer argued that realists should...
Let's prepare and experiment with individual photons moving along the z-axis and polarization in the xy-plane such that a detector registers
- polarization along the x-axis with 90% and
- polarization along the y-axis with 10%
According to the MWI for each registered photon there's a...
Hi all,
I am trying to hard to understand integral's transform.
While an interpretation of Fourier transform is relatively easy to furnish in terms of signal decomposition and harmonics, it seems the "meaning" of Laplace transfrom is more subtle (in spite of the similarities between the two)...
I have heard that Schrodinger's interpretation of his equation is different from the modern interpretation. What was Schrodinger's interpretation of his own equation and what did he think ψ represented?
Hello,
I am approaching the end of my multivariable/ vector analysis "Calc III" class and have a question about flux.
My book states that flux, ∫∫ F \bullet N dS measures the fluid flow "across" a surface S per unit time.
Now, the divergence theorem ∫∫∫ divF dV measures the "same...
The question of Solving a Pfaffian ODE can be interpreted as the question of finding the family of surfaces U = c perpendicular to a surface f generated by the vector field
$$F(x,y,z) = (P(x,y,z),Q(x,y,z),R(x,y,z))$$
At each point, the gradient of the family of surfaces U = c will either...
I've always thought of the gradient of a scalar function (id est, ##\nabla\varphi##) as being a vector field. However, I started thinking about it just now in terms of transformation with respect to coordinate changes, and I noticed that the gradient transforms covariantly. Thus, shouldn't the...
hi there. I studied physics for years, even went as far as getting a PhD. but that was 13 years ago, since then rusty. Anyway something occurred to me and I wondered what you all would think about it.
My question is, can anyone think of an experiment you could do to check if the "many...
The Schrodinger's cat thought experiment provides two possible outcomes in the many worlds interpretation; it is dead in one universe, and alive in the other. There are however many other possibilities of what could happen; there are wave functions concerning the positions which the cat may...
Hi all. I've been thinking about this question a lot for the past few days and it seems to me that I'm committing a mistake somewhere along the way, but certainly can't figure out where. Here's one of the interpretations which I've encountered most frequently and think is the right one (here's...
In Zee's book at page 12 in both editions he finds that he can write the amplitude
$$\langle q_f|e^{-iHT} |q_i\rangle = \int Dq(t) e^{iS} $$
where T is the time between emission at ##q_i## and observation at ##q_f##. He then states that we often define
$$Z = \langle 0 | e^{-iHT} |0...
There has been a narrative that has run through a number of posts on special relativity. It establishes the idea that LET (Lorentz Aether Theory) is an interpretation of SR (Special Relativity).
I personally believe this is a false narrative and that there is at least one fact that must be...
Attached you will find the torque vs engine rpm and power vs engine rpm curves for an 'ideal engine' and also for a 'normal SI engine'. 1.(for the 1st ideal engine curve) Is it 'ideal' that the torque curve should decrease as the engine rpm increases? Why?
Does this mean that 'ideally' in a...
When one says that <\varphi|\psi> is the probability that \psi collapses to \varphi, does this "collapse" necessarily involve a measurement (so that one would have to find the implicit Hamiltonian)? Or does this just exist as part of the evolution of the wave function, perhaps the vacuum energy...
I understood the derivation of relativistic momentum, but I am uncertain of how to exactly interpret it. One could interpret the arrangement of terms to be relativistic mass times velocity, and this appears to be in agreement with data from particle accelerators (or so I have been led to...
Can there be an experiment (even a thought experiment), which could settle the debate CI vs MWI? Now a days many scientists seem to favour MWI. I find it interesting because it perhaps allows time travel (the possibility of an observer going back to his/her own past) while avoiding the...
Ive been learning a lot about how similar waves and particles are at the fundamental level, but today i was assaigned to discuss the difference between the CLASSICAL physics of particles vs Classical Physics of waves.
Differences and similarities and well as how momentum is/isnt diferent as...
In reading about the axial anomaly I stumbles across a matrix element on the form
$$\langle p,k|j^{\mu 53}|0\rangle. $$
and I have seen similar matrix elements turn up other places. But when matrix elements (correlation functions) of the form
$$ \langle 0 |T \phi(x) \phi(y)|0\rangle $$...
Three related questions on which I could use some help:
a] In another thread, Bill_k posted something like:
"Electrons, being charged, could exchange energy by exchanging a virtual photon."
ok, yet I thought electrons usually interacted via the EM field ['real' photons]...
So how...
Hi everyone, I'm a new member but it's not the first time I look at the forum.
Well, I don't know if this is the right section to post my question. I think it is related to quantum mechanics interpretation too. Anyway, let's have a look at my problem.
I've computed cross section for photon...
Can the cosmological redshift be interpreted as atomic frequencies increasing by the scale factor as the Universe expands?
This explanation seems closer to the truth than the popular idea that a photon's wavelength somehow expands while it travels to us from a distant galaxy. Metric expansion...
I get the basics of the interpretation, but I don't understand one specific element. If there are parallel worlds, where is this parallel world? Is it like a stack of newspapers, each page being a different world, where the entire, connected newspaper is the universe? What I'm asking is if this...
Considering e is the limit->+oo of (1+1/n)^n, then is e "what you get if you wait for the least gain, by waiting for the most amount of time"? Something like "e is the patience number".
Hello, I know this question may be absurd or very basic, but I need to know what it means when two variables with different units are being multiplied.
I need to know what multiplication is in physics, in order to make sense of formulas (such as momentum, force, energy formulas) without only...
This is from Wikipedia regarding the first point of the Copenhagen Interpretation:
What does it mean to make a measurement? Is this something that only living beings do or can a dead particle make a measurement? Why does measurement collapse the wave function.
Tell me how you understand this question. I've removed the details of the calculation to focus on the language and how certain ideas should be expressed. I know it's a weird thing to ask so just try to answer how you can.
Calculate __________ for each $v_1, v_2, v_3$ and $p(t)$.
(The following is a purely qualitative consideration of Quantum Mechanics)
In a particular Quantum Mechanics text, I've come across the following quote which I'm having some difficulties interpreting.
"We describe the instantaeous state of the system by a quantity \Psi , which satisfies a...
I've been taught (in the context of Sturm-Liouville problems) that Fourier series can be explained using inner products and the idea of projection onto eigenfunctions in a Hilbert space. In those cases, the eigenvalues are infinite, but discrete. I'm now taking a quantum mechanics course, and...
Hello. Before I ask a question I want you to remind that it is my first time to use this page. And I am not even good at speaking english. My question is about the fictitious forces. I have made a long proof for the formula of the force in the non-inertial reference frame with the second law of...
Green's function?? Physical interpretation??
Hi friends..
Can anyone help me to understand the physical interpretation of the green's function with help of some physical application example such as that from electrostatic?? I am unable to understand what is meant by linear operator in green...