Which path Definition and 28 Threads

The Delayed Choice Quantum Eraser (DCQE) experiment attempts to show that which-path information can be "erased," and interference recovered. I'll refrain from explaining the experiment, and assume you are familiar with the setup. I refer to the Wikipedia page about it, and the original Kim...

I've found an interesting problem in an undergrad physics book which I've bought, and my high school teacher to whom I've showed it said it was intriguing, and didn't know the answer. A tube in the shape of a rectangle with rounded corners is placed in a vertical plane, and inclined towards the...

Hi. As far as I understand the Franson interferometer, the photons are in an entangled state like $$\left|\Psi\right\rangle=\frac{1}{\sqrt{2}}\left(\left|\text{short}\right\rangle\left|\text{short}\right\rangle+\left|\text{long}\right\rangle\left|\text{long}\right\rangle\right)$$ if the setup...

All the literature on the quantum eraser that I've seen is grounded in the Copenhagen interpretation of quantum mechanics. It's very easy to understand the experiment in those terms. Do you know how quantum eraser experiments are interpreted by the de Broglie–Bohm theory? What is erased in this...

$\tiny{243.13.01.19}$ $\textsf{The following equations each describe the motion of a particle.}$ $\textsf{ For which path is the particle's speed constant?}$ \begin{align*} \displaystyle R_1(t)&= t^7\textbf{i}+t^4\textbf{j}\\ R_2(t)&= \cos(3t)\textbf{i}+\sin(8t)\textbf{j}\\ R_3(t)&=...

Hi. In a Mach-Zehnder interferometer, there are mirrors in both paths. When a photon gets reflected on a mirror, it transfers momentum. Also, mirrors are classical objects that are usually not assumed to exist in superposition states. Shouldn't it (at least in principle) be possible to measure...

Guys I have the following homework problem to solve: There are 2 given points in a plane. If we take a point-like object with mass m and take it to the "higher" point what path should it go on to reach the other point in the shortest possible time. Only gravitational force affects our point-like...

I am new here so I will start with a warming up question :) My question is very trivial here we go: In double slit experiment when shooting one photon at a time, we get interference pattern. Then when we put a sensor at one of the slits the interference pattern disappears because we now know...

Hi everyone, i'm a student from Quebec in pure science in college. I have two weeks left to register for university. Having listen to people and read, I'm really worried about my path. I really want to study physics for undergraduate since i find this really interesting. Where I'm worried is...

I'm now at my sophomore year in college, studying Mechanical Engineering. When I chose this field, I was interested in things like aircrafts and my main goal was working in the aerospace industry. This interest has shifted towards control systems/robotics since then. I started dealing with...

In 2012, experimenters showed that when two entangled photons separate and when one goes through the double slit, we can tell which slit it went through and see that they still created an interference pattern because the photon that it was entangled to tells us which slit it went through. What...

Homework Statement using complete diode model explain which path will the current follow? given dynamic resistance is 240 ohm.compute current. 2. The attempt at a solution when we make complete diode model, ideal diode will be replaced by a switch and the given dynamic resistance. the silicon...

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...

I found this mechanism(see image) in a very old book in the library.I was wondering if there is any mathematical technique(obviously geometrical) to find out the locus of travel that the links would take(case 1). Also, be able to calculate the displacements(case 2). The problem with the given...

I don't know if I got this right, but as far as I know, if you are able to deduce through which slit the particle went through, it behaves classically, if you have no way of deducing through which slit the particle went through, it behaves in a quantum way (interference pattern). Now, I don't...

I am reading a paper from Yakir Aharonov and others revisiting Hardy's paradox and I have a question. Let me state the notation first as brief as possible so that we can use it in the discussion: * a positron e+ goes through either the overlapping arm o+ or the non overlapping arm no+ of a...

I know this is not possible but I want to know why. Why cannot a directional photon (or electron) detector placed on the screen of a 2 slit experiment detect which slit an individual photon comes from without destroying the fringes? Fire the photons one at a time. They can be detected...

I would like to know whether it is possible to determine which path information for a photon reflecting from a mirror as shown in the book QED by Feynman page 40 and 43 (or available by googling mirror reflection Feynman or similar) if photons are fired one at a time from the source (unaimed)...

Hello, I am currently in engineering (Electrical Eng), but i already have issues with which stream i should focus on, right now these are my interests are: digital electronics, software/hardware,energy system:control, and energy system:high power. As anyone i want to secure a decent job and...

Hi, I'm currently going into my second year of university as a math major and I am strongly considering becoming an actuary. I really enjoy math and physics, so I'm minoring in physics at the moment, though that may have to change for more business courses. I would therefore love a job that...

Hello all. I'm a recently graduated high school student entering a liberal arts university. Right now, my intention is to major in physics. But I'm concerned about several things: First, I'm concerned about whether there are any career opportunities for a physics b.s. I've heard that physicists...

This is a two part question. Part 1: I am embarrassed to ask but if someone could please help me. I was thinking about a train car moving at a constant speed which had a simple apparatus onboard. A light source on a pole which emits light straight down only (say a laser of some kind). Below the...

Hi there, this is a problem I'm having since last year, and should be "very easy", and i guess it is. 3 long years ago i took the complex analysis course, and I've used so little of it until now, that i almost forgot everything of it. The problem is this, I have the following integration...

Hello everybody! I'm currently in the last year of my undergraduate studies in physics and I'm really happy because I'm finally having the chance to focus on what I like, Astronomy. Next year I'll be starting a Master Degree in the National Observatory here in Colombia but I'm also planning...

Hey, I'm entering into my junior year at the University. I'm a chemical engineering student. Right now I've been following the biology track in my program. Recently my college has developed a nuclear engineering minor which seems very intriguing. If anyone can give me any incite on which...

which path should I choose?? what career should I choose? a theoretical physicist or a nuclear physicist? I want one that pays good, but mainly which one would be more exciting, I like both of them very much, I wouldn't mind either, just the one that pays a good salary, and is the most...

Hey guys i was just wondering how hard is it to find a job after getting a BS in EE because today my professor said he has been in the industry for about 10 years and it isn't easy getting a job and he told us to just go to grad school instead, which is kind of discouraging so i was just...

Greetings. I just found these forums and hope you guys can shed some light on this for me. I just received my AA degree from a local community college and am finishing up Physics 2 and Calculus 3 so I can move on to the University of Central Florida. I would like to get into the Masters...