Path Definition and 1000 Threads

Hello, my name is Marcos. I am 18 years old and I am from Argentina. I am going through quite a struggle deciding between Physics, Engineering(specifically Aerospace Engineering) and biology.The reasons for my interest in physics are: I would love to carry out research(I like science), I like...

Homework Statement Consider an ideal monatomic gas that undergoes an adiabatic free expansion starting from equilibrium state A with volume 500 cm3, pressure 40 kPa and temperature 300K to state B, which has a final equilibrium volume of 1000 cm3. Construct an reversible isothermal path that...

An astronaut on a revolving space station releases a wooden spoon out of the satellite, into empty space. Will the spoon fall toward Earth ? What will happen next ?

On the attached picture I have started trying to derive the path integral but I don't know how I get further. Can anyone help me? Also I have used that: exp(-iHΔt/ħ) = exp(-i(T+V)Δt/ħ) = exp(-iTΔt/ħ)exp(-iVΔt/ħ) But my book says that this identity is only correct to first order, i.e. there is...

Let me post this question again in a slightly modified form. On the attached picture the path integral for the partion function: Z = Tr(exp(-βH)) Now according to what it says on the picture it should be easy from this to get the Green's function in the path integral formalism. The Green's...

There are plenty of proofs for the statement, but I do not find one which is not rely on other assumptions. Here are some common proofs of this statement: https://en.m.wikipedia.org/wiki/Great_Circle#Derivation_of_shortest_paths This proof require the path to be differentiable, which is not a...

In my book the path integral representation of the green's function is given as that on the attached picture. But how do you go from the usual trace formula for the Green's function 2.6 to this equation?

Homework Statement A Michelson interferometer is illuminated with a laser with a wavelength of 514.5nm. A Haidinger fringe pattern is photographed with a lens of focal length 55mm. The diameter of the two adjacent circular fringes in the image are 1.53mm and 2.62mm. How far would the mirror...

Homework Statement A Michelson interferometer is illuminated with a laser with a wavelength of 514.5nm. A Haidinger fringe pattern is photographed with a lens of focal length 55mm. The diameter of the two adjacent circular fringes in the image are 1.53mm and 2.62mm. How far would the mirror...

Homework Statement A thin film of dielectric material of refractive index 1.455 and thickness 6.50 mm is now placed over one of the slits (say the right-hand one). By how much will this change the optical path between the slit and the centre of the screen? Homework Equations Optical Path...

Hi, I'm 23 and I go to gateway community college in new haven ct. I have been taking my core credits and it is now time to pick a degree. My original intention was to get my accounting degree (fathers choice), but I despise it. My school has a few engineering programs and I'm 95% positive that I...

Homework Statement There are three objects at the Vertices of an equilateral triangle that start movin towards each other at the same time with a speed v. Describe the path of the objects and the time taken for them to meet. Homework Equations V1=v3 - v2 Where all velocities are in...

I am reading about the construction of the path integral in which states that the propagator is given by: <qf l exp(-iHt/ħ l qi > = ∫Dq exp(i/ħ∫dt L(q,q')) and Dq is the integration measure given by limN→∞Πn=1N-1 dqn. Can someone help me understand this integration measure a bit better? I...

I've searched the internet and found a few sites, of varying depth, that contain some of the equations to calculating the solar path. At the moment, I'm not particularly concerned with precision. I am trying to discern the equations in order to implement them into a java program I am writing...

I am trying to conceptually connect the two formulations of quantum mechanics. The phase space formulation deals with quasi-probability distributions on the phase space and the path integral formulation usually deals with a sum-over-paths in the configuration space. I see how they both lead...

In Chapter 7 of John M. Lee's book on topological manifolds, we find the following text on composable paths and the multiplication of path classes, [f] ... ... Lee, writes the following:In the above text, Lee defines composable paths and then defines path multiplication of path classes (not...

Homework Statement In plane parallel plate the refractive index is a function of coordinate ##z##, so that ##n=n_0 -{n}'z^2## for ##{n}'>0##. The origin of the coordinate system is in the middle of the layer, and ##z## is parallel to the normal of the layer. In paraxial approximation calculate...

Hello everyone, my name is Mike, and i am 18 years old. In a month from now, i am going to be giving the national exams my country does to qualify for a university. Unfortunately, there is no idea to know in which university i'll pass, if i pass at all. These exams are known to be difficult...

Here's the source:http://web.mit.edu/dvp/www/Work/8.06/dvp-8.06-paper.pdf Regarding page 5 of 14, I don't understand the multiple integrals thing. What is that supposed to mean? Ain't we supposed to sum up all the paths but why do they do the multiple integral thing? Also regarding page 4 of...

Are the integrals of the function f(z) = (1/(z-2) + (1/(z+1) + e^(1/z) path independent in the following domain: {Rez>0}∖{2} The domain is not simply connected I know that path independence has 3 equivalent forms that are 1) Integrals are independent if for every 2 points and 2 contours...

Hello! (Smile) Longest path We have a graph $G=(V,E)$, lengths $l(e) \in \mathbb{Z}^{+}$ for each $e \in E$, a positive integer $K$ and two nodes $s,t \in V$. The question is if there is a simple path in $G$ from $s$ to $t$ of length at least $K$. Show that the problem Longest Path belongs...

Homework Statement [/B] A shark will in the direction of the most rapidly increasing concentration of blood in water. Suppose a shark is at a point x_0,y_0 when it first detects blood in the water. Find an equation for the path that the shark will follow by setting up and solving a...

Can you explain the sort of sinusoidal path here: http://i.imgur.com/vN7PJCu.gif

Hey, Most related questions here specifically talk about torque, force, angular momentum/velocity etc. I just want to know how I can aptly describe the motion of the tip of some string as it wraps around a cylinder. So basically, the path of an object in circular motion with a decreasing radius...

Homework Statement An optical fiber is one way to guide light efficiently from one point to an other. It is currently used for data communication: it offers low loss and very high bandwidth, ideal for the requirements of the internet. Generally, we can describe an optical fiber as a medium with...

Hi, I want to varify something that I intuitively know (I think), that might not seem intuitive. If an electrical current is circulating and then it's path splits in two, where there is a circulating current. The larger current (black) will have to pass through this loop; what I want to varify...

First post, but have seen some great information while lurking. Here is the situation. I am 35. I dropped out of high school and entered the IT world at age 17. I went back and got my GED at 25 (got tired of lying on applications!). I have always had gainful employment. I work in telecom...

Homework Statement A projectile is launched from a mountain at a given angle and velocity (which is large). Using polar coordinates find the position of the particle at time t. I'm ignoring drag (for now). Homework Equations I tried using the polar kinematic equations...

I am currently computer engineering student(second year). Well its not like I don't like computer engineering.but somtimes I think I should have chosen another path.I am pretty good at mathematics.I like to solve maths problems.I am also fascinated about cosmology.I like electronics as well.I...

Is there any direct experiment to determine the value of mean free path(not the distribution) of a gas molecule?

Is there such a thing as a Feynman Path Integral for two non-interacting particles? I find myself wondering how the wave function of a single particle is changed in the presence of a second particle. The Feynman path integral takes into account every possible path that a particle can take. So...

So I was doing a circuit with some friends, and the circuit breaks down such that There is what looks like a parallel circuit, with one branch containing just the wire, and the other branch containing a resistor. The answer to the question shows that the electrons will not flow through this...

so this is the question I'm having a little trouble with: Assume that the ratio of copper resistivity at room and absolute zero temperatures (so called "residual resistance ratio") is 1000. Estimate the electron mean free path in copper at low temperatures. we also know this: Let us assume...

Feynman Path Integrals are a way of calculating the wave function of quantum mechanics. It usually integrates every possible path through all of space. I wonder if there is any study of Feynman path integrals through a space with holes in it - with regions of space excluded from the integration...

Hello, I have write a fortran code to write several file, like this CHARACTER(len=12) :: FNAME INTEGER::ST DO 100 ST=1,12 DO KC=1,4 !number of layer IF(ST.EQ.1) WRITE (FNAME,10)KC IF(ST.EQ.2) WRITE (FNAME,11)KC IF(ST.EQ.3) WRITE (FNAME,12)KC...

It seems to me that in a path integral, since you are integrating over all field configurations, that going into Euclidean space is not valid because some field configurations will give poles in the integrand of your action, and when the integrand has poles you can't make the rotations required...

So I've just recently started learning path integral methods in QFT and string theory, and I've heard from numerous sources that the path integral (specifically fermionic path integrals, perhaps?) are objects which are not at all on solid mathematical ground. The feeling I get is that perhaps...

Homework Statement Calculate the average vector velocity between 0 and pi/4 sec. Homework Equations x=rcos2t y=rsin2t Vx=2rsin(2t) Vy=2rcos2t Ax=4rcos(2t) Ay=-4cos(2t) Circular path is x^2+y^2+r^2 The Attempt at a Solution I'm not sure if I am missing something simple or not, What I need to...

Homework Statement Temperature varies by function T(x,y,z)=3x + 4y + 2z Path is given by r(t)={ x(t)=\frac{t^3}{30}+\frac{16t}{9}+7 y(t)=-\frac{t^3}{120}-\frac{13t^2}{30}+28 z(t)=\frac{13t^2}{60}+\frac{4t}{3}-14 t\in \left[0,10\right] Question: What is the maximum and minumun temperatures of...

Homework Statement John is thrown into the outer part of a circular den of radius a. At the centre of the den is a Lion. John decides his best tactic is to run round the perimeter of the den with his maximum speed u. The Lion responds by running towards John with its maximum speed U. (i)...

Somebody asked about this but that thread was closed very soon. In physics, discontinuous paths breaks locality so they must be 0; but mathematically, they causes some problems. Discontinuous functions must not be differentiable, so it's impossible to calculate the action over that path. However...

Hi, I'm reading that a particle located at any given point can, in the next moment, be at any other given point in the universe. My understanding is that this is a correct interpretation of quantum physics. So, my question is, how does the particle 'decide' where actually to be in the next...

Homework Statement Given position function r(t) and r'(t) = c X r(t), where c is some constant vector, describe the path of the particle. In other words, describe r(t). Homework Equations // The Attempt at a Solutiona) r'(t) points in the direction of motion. If we can understand how r'(t)...

Feynman's first topic in his second lecture on QED is the nature by which light reflects off of a mirror. We work in ##\mathbb{R}^2##. Suppose we have a light source sitting at ##(-1,1)## and a photomultiplier sitting at ##(1,1)##, with a mirror along the x-axis. We also place a block between...

Homework Statement What is the mean free path of an N2 molecule in an ultra-high-vacuum chamber at a pressure of 10-10mbar? Homework Equations λ=1/(√2)nσ number density n, collision cross-section σ p=nkT pressure p, temperature T σ=πd2 d molecular diameter The Attempt at a Solution...

Hi! Long story short, I studied Civil E (Structural and Geotechnical), which it turns out I don't like. On the other hand, I found over the years I really like Electrical E. I don't have neither time nor money to go back to school, but I'm determined to learn some of it on my own. Because I...

I know that The path Integral becames classical Lagrange (Classic Mechanics) how can it be turn it.

What's the main logic of path integral formulation ? (Feyman path integral formulation) I mean what's the reason to think this way ? Thanks

So I've been thinking about the axioms of quantum field theory. In particular the expression for the particle amplitudes: G(x1,x2,...,xn) = ∫Φ(x1)Φ(x2)...Φ(xn)ei S[Φ]/ħ D[Φ] / ∫Φ(xn)ei S[Φ]/ħ D[Φ] But I've been struggling to explain the existence of the 'i'. It seems like this is a...

http://www.pluggakuten.se/wiki/images/3/3e/Prov221.JPG Solution