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.
In a metallic system, the Fermi level is crossed either from the conducting zone into the non-conducting zone or vice versa.
Is there an interpretation one can give to the direction of the crossing? In other words, if the 1D band gap diagram shows the fermi line is crossed from the...
Hi,
I've been reading a QM book and it mentions that particles can be represented as a wave packet, which provides a description for particles simultaneously as a wave and particle.
It also mentions that the wave packets disperse, and the width becomes extremely large for free microscopic...
Greetings everyone,
I'm going through Griffiths QM, and just wanted to make sure I understood the roles (where they come from, etc.) of the quantum numbers n, l, and m. What is written below is basically an outline of my current understanding, of which I am seeking either a confirmation or...
Most physicists don't draw a distinction between past, present and future.. this is called the arrow of time. Physicists such as Sean caroll, Paul Davies e.t.c But if all events exist in some sense then the future is <not> open.
If the future is not open then determinism is true.. thus...
As the poll on this forum from 2011 that has recently been resurrected shows, there are a portion of the users here who adhere to the modern reading of the Everettian interpretation.
What I have never seen discussed here though is the issue of whether the worlds split(overlap) or...
moseley did experiments on various elements and showed that the frequency of the k-alpha emission was proportional to the square of the proton no.
The formula is (z-1)^2 proportional to the square root of frequency, with the -1 thrown in for the screening effect.
The bohr model can explain...
Hi, I've started to watch some lectures on quantum mechanics & they're going well except for the fact that some of it makes no sense. Basically I just don't see how |ψ|²dτ represents the probability of finding a particle described by ψ in the volume element dτ. Most likely it's due to me having...
When a vector field representing a physical quantity (e.g. B) has ∇\cdotB = 0 what is then the physical interpretation of this? Some people have said that the field doesn't diverge away from anything, but as far as I can tell magnetic field can easily get weaker and weaker the further you go...
Where exactly do the probability distributions we observe come from under the many worlds interpretation? I know it has something to do with being the only stable configurations in Hilbert space but I don't understand why.
This is my attempt to explain it in my own way, please tell me if it...
Homework Statement
The problem along with its solution is attached as ProblemSolution.jpg.
Homework Equations
Δx = λ/sinθ (Eq. 1)
Δp_x = (h/λ)(sinε) (Eq. 2)
The Attempt at a Solution
In Wikipedia, I found this article: http://en.wikipedia.org/wiki/Heisenberg's_microscope which uses...
Quantum field theory predicts a value for the cosmological constant that is 123 orders of magnitude larger than the observed value (if one assumes the Standard Model to be correct up to the Planck scale of 10^19 GeV)! To theoretically predict the value of the cosmological constant, one must, I...
Hi there.
I am an Aerospave Engineering student, revisiting Vector Mechanics. My course recommended textbook is "Vector Mechanics of Enginners, from Beer and Johnston". However, I have been complemeting with another book - " Methods of Analytical Dynamics, from Meirovitch". This book, treats...
Hello!
I'm doing a modal analysis and I'm trying to extract modal parameters from my aqcuired data. I'm using the Pulse Reflex Software.
I got to the point where the Software provides me with a MIF and a stability diagram and I am to choose the parameters. However, I am unsure how...
Hi,
I would like to study SL(3,\mathbb{R}) a little. I was motivated to look into them a bit because of their volume-preserving nature. Now this group has n^2-1=9-1=8 generators and I found out through some reading that three of them are the generators for rotation (duh Judah, volume...
Hi all,
I am working through Visser's notes http://msor.victoria.ac.nz/twiki/pub/Courses/MATH465_2012T1/WebHome/notes-464-2011.pdf section 3.5 onward. I am trying to differentiate between the torsion and the Riemann curvature tensor in a heuristic manner.
It appears from "Geometric...
I'm currently trying to make some intuitive sense out of Quantum field theory, but I'm not really understanding the vacuum.
Consider a real (or complex, with + in the right places) scalar
particle (a Klein-Gordon field).
Now consider the propagator (or correlation function)
G(x-y)=...
I noticed a youtube video, where Thomas Warren Campbell, a physicist and author of the book trilogy My big TOE the last standing for Theory of Everything and apparently he also works for NASA, deducts some very disturbing things from a certain double slit experiment.
Here it is, I marked the...
From what I understand, a basis is essentially a subset of a vector space over a given field.
Now what I'm not so sure of is the linearly independence part. If the basis has two linearly independent vectors, then than means they aren't collinear: rather, they wouldn't have the same slope...
When we calculate the average of anything: we add up (or integrate) the sum{ [all the things were taking the average of] * [the probability of getting that thing ]}.
The thing about the average I'm that curious about is for example: the average height of 5 people turns out to be say 6...
http://dl.dropbox.com/u/33103477/Resistor.png
For the first bit first I solved the equation
\frac{dI}{dt}=\frac{U-RI}{L}
I(t)=\frac{U-C_2e^{\frac{-t}{L}}}{R}
Now I put in T(0)=0 to work out the constant and I got
I(t)=\frac{U-Ue^{\frac{-t}{L}}}{R}
Now here's the dodgy bit, I did...
Im really just searching for a general explanation!
If you are solving a pretty standard left hand side differential equation, but a diracs delta function on the right hand side. I am abit confused about how to interpret this.
If this is the case for the right hand side:
r(t) = Diracs (t)...
Homework Statement
Now , analyze the data with a power function least square fit. Let the x values be the length and the y value be the period.
From the results of the power fit, compare the experimental value of the period to that calculated USING THE POWER FIT YOU JUST DETERMINED...
http://dl.dropbox.com/u/33103477/Linear%20oscilator.png
I am having trouble understand the question, what I have done its solve the equation using the substitution x=e^{rx}
Then, I have the solution given by:
x(t)=c_1 e^{t(\sqrt{\gamma^2 - \omega^2 })} + c_2e^{-t(\sqrt{\gamma^2 -...
I am a programmer by trade, so I am more adept at logic than mathematics. One thing that has always perplexed me about the Michelson-Morley experiment was how it is used to reach the conclusion that there is no ether. Just given basic logic, there is a third alternative that I have never seen...
We are starting to learn about spin in my introductory quantum mechanics course, and I was wondering if anyone could provide a physical interpretation of an electron's spin. I understand its a form of angular momentum which has nothing to do with the motion of the electron in space, but since an...
Wikipedia: "Reynolds Number is a dimensionless number that gives a measure of the ratio of inertial forces to viscous forces."
What is meant by the inertial forces?
I have a much better intuition of viscosity. But it seems to be like the Reynolds Number predicts turbulent flow for a...
Statistics question: I'm having trouble understanding my statistics professor's objection to this interpretation of confidence intervals.
If you have some distribution with parameter x: X = Dist(x), and you perform a random experiment drawing N random variables from it, and derive from those...
I will try to keep things brief. I am trying to understand what is considered interpretation.
Imagine we have a totally isolated and complex quantum system in a fixed initial state which we can prepare with essentially perfect fidelity. Suppose that this system is macroscopic in which small...
Can the covariant components of a vector, v, be thought of as v multiplied by a matrix of linearly independent vectors that span the vector space, and the contravariant components of the same vector, v, the vector v multiplied by the *inverse* of that same matrix?
thinking about it like that...
Homework Statement
A student takes a 30-question mathematics exam on which she got n questions correct and m questions incorrect and left k questions blank. If correct answers are worth 4 points, incorrect answers are worth -1 points, and blank answers are worth 0 points, write an equation to...
Hey,
I had this question I thought i answered but now I'm questioning if the group operation is supposed to be addition and not multiplication.
The question \varphi :\mathbb{Z}\to {{\mathbb{Z}}_{n}}\,\,\,\,\,where\,\,\varphi (a)=\text{Remainder}\left( \frac{a}{n} \right)
When I...
I know, I know, it might be a little bit spam-y to post another poll, but since the option 'Other' was gaining so much attention, I decided to create a new poll with more options so that people could be more accurate in their description.
Since I support the MWI, I will post a few links with...
I was wondering who/how many people in the forum subscribe to which interpretation, so I decided to make a poll :)
Also anyone is welcome to post content about each interpretation to illuminate people who may not know the difference and/or definition of an interpretation.
Two individuals A and B are traveling through space at a velocity in the "x" direction at and are next to each other so they can synchronize their clocks. Since there is no other available reference they believe they are not moving. Both have a duplicate shape charge which as they are in the...
Hi,
I am am currently taking a second course in geometry, the first part of the course concerns projective geometry, and I feel I'm not getting the picture. I would like to know what the motivation for the development of projective geometry is. What picture you guys have in your head of...
This is an extract from the lecture notes I took for the 'Foundations of QM' third year course.
Copenhagen QM - classical-quantum division
State: wavefunction ψ(x); (ψ,\varphi) = \int d^{3}r ψ^{*}(r)\varphi(r)
Evolution: TDSE
Observables (\hat{x},\hat{p},\hat{H}): A = A-dagger...
Interpretation of "dx" as the differential of x for Indefinite Integrals
This question is concept-as-opposed-to-calculation based. I understand that when one sees the integral sign, followed by f(x)dx, that we can think of this as the indefinite integral, or antiderivative of f(x), with...
I have this physical chemistry this semester with a very small section on thermodynamics--namely the Second Law and its applications to feasibility of reactions.Because our class is not very familiar with the Second Law(this is our second sem and we were taught only the First Law in school)our...
Hello,
I have been following this forum for some time now, but this is the first time I participate. I would appreciate if you could give me a hand in understanding the results of a finite element analysis of an automotive component we have designed.
The analysis results indicate that the...
There are tons of interpretations of quantum mechanics, but I'm unaware of any that are 'classical' as in being local, having realism and determinism.
There is Bells famous work proving that that can't be true for certain aspects of quantum mechanics, but why aren't there any classical...
I was watching "The Fabric of the Cosmos: What is Space?" on pbs.com, and I couldn't help but wonder a few things after looking up some information about it.
I find it funny that people have been using String Theory with only two dimensions (since they are supposed to keep adding dimensions...
hello forum,
we all know that a rotation wheel, a rotating football, etc.. maintain their direction of motion with more stability than if they were not spinning...
A bicycle wheel is suspended from one of end of its axie by a rope, and spun up by hand. The wheel's axle is then placed...
Hello,
Before I ask, I'd just to say that I know this has been heavily discussed before, but I am asking for peoples' insight directly as this is for a report I'm currently working on, hence why I'm not just looking through old posts using the search option. So I'm sorry if this may be of an...
Hi,
I would be interested in what people think of the following experiment.
Imagine a laser beam is split into two coherent beams A and B that are made to cross each other at right-angles. Beyond the point of intersection let us assume that there is a detector A in the path of beam A and...
Let r = √(x^2+y^2+z^2)
One can easily show that \nablar= \vec{r}/r.
But I'm having a hard time understanding what this means geometrically - who can help? :)
Hi,
I was at a party where there was a lucky draw. There were about 200 people and each of them had put a chit with their name on it, in a transparent bowl. There were 10 prizes. The announcer chose a person at random to pick a chit for each prize. For one of the prizes, the picker picked his...
Theorem : let A be a set of formulas, a be a formula
For all A and all a,
Every interpretation which is a model of A is also a model of a iff
not (Sat A) U {~a}
Proof
Every interpretation which is a model of A is also a model of a
iff(1) there is no interpretation which is a model of A but...
Given \triangle u = f(x,y,z) on a given body with vanishing neumann boundary conditions. I'm asked to interpret it in terms of heat and diffusion.
Since heat/diffusion take the form u_t = k \triangle u, I am a little confused as I there is no time term here. I think the answer is that u...