Choice Definition and 667 Threads

Hi all, I've just been made offers to two different institutions - one to study General Relativity and Early Universe Cosmology, and one to study particle physics phenomenology and dark matter at PhD level, and I'm having a hard time choosing! Relativity and Cosmology is Queen Mary University...

You get access to superpowers. You can choose three superpowers from the following list: You will know and understand the knowledge of any book you touch. Your mind will be upgraded with a powerful computer. This implies you gain the processing speed and the memory of a supercomputer. But this...

I have recently been accepted as a major in Physics to UCR, UCI, and UCSB. I know that UCSB is the highest ranked of all the UC's in Physics particularly (except Berkeley, which I did not get in to), but my main dilemma here is that there are other factors in play. With where I live, I could...

Hello everyone, Greetings of the day. My name is Zeshan, I am automation engineer, I am stuck in problem of automation of weighing and sort system in chicken slaughter house using plc and load cell. Everything is done right but load cell is not giving me the right weight to make the right...

I watched this video that dumbs down and explains very simply how the quantum eraser works From my understanding: The particle will go thru both slits if not observed (probably wave collapsed). If you setup a device that will detect it (that emits a photon if the particles passes thru) the...

Homework Statement http://gpschools.schoolwires.net/cms/lib05/MI01000971/Centricity/Domain/272/Chapter%205%20MC%2013.pdf It is problem 22 on page 7 of the document: A block of mass M1 on a horizontal table is connected to a hanging block of mass M2 by a string that passes over a pulley, as...

Hi, I have a simple question regarding this experiment: If we were to place a new detector, say D5, immediately after BSa, would it mean that D0 never shows an interference pattern for D5? I think so, as it would seem this should be no different than the result obtained at D3, but just want to...

If I understand the delayed choice quantum eraser experiment correctly, it's essentially set up in the manner as the double slit. The only difference is that the detectors are set up in front of the double slits. It was thought that if there was an interference pattern that appeared then that...

Homework Statement If the vector B⃗ has a magnitude of 45.0 m and makes an angle of 60.0 ∘ with the +x axis, the vector -B⃗ choices: 1. has a magnitude of 45.0 m 2. has the same direction as B⃗ , but a magnitude of − 45.0 m 3.makes an angle of − 60.0 ∘ with the +x axis 4. has the opposite...

Homework Statement I found this problem online for extra practice for my AP Chem class. https://www.quia.com/files/quia/users/jpugteach/APChem/AP-Chem-Chapter-19-Graphs.pdf The problem in question is number 4. I do not understand how to solve it and why the answer D is correct. Homework...

In page 4, Peskin and Schroeder has the following diagram: The diagram shows the collision of an electron beam and a positron beam to produce a ##\mu^{+}## beam a ##\mu^{-}## beam. My question is this: The electron and positron beams are shown to have momenta ##\textbf{p}## and...

Homework Statement I want to extract and quantify lipids inside the starch. Which solvents you recommend for the extraction? Homework EquationsThe Attempt at a Solution

Hello, I will try to keep it short here. I want to be a professor (Physics or Engineering) but from what I am reading, it seems like a large amount of work with little pay. I have a few questions about this topic and was wondering if anyone could shed some light on it. 1.) What are the...

With this new publication in Nature, http://www.nature.com/nphys/journal/v11/n7/full/nphys3343.html, they have proven that "if one chooses to believe that the atom really did take a particular path or paths then one has to accept that a future measurement is affecting the atom's past." Do...

There is a perfect software program that can answer "everything" you ask. Can this software program predict a posible non-existent random choice (of 2 objects) in the past chosen by another perfect software program that answers competely random? The choice is completely random but it never...

I'm trying to create a simplified diagram of the delayed choice quantum eraser experiment (contrast with the confusing one on Wikipedia and the simplified one on some random site). Here's what I have so far: Context that goes with the diagram: it is understood that an entangled pair of...

Homework Statement A book of mass m is sitting on a table of mass M. Which of the following statements regarding Newton's Laws of motion is true? (a) Newton's Third Law says that the magnitude of the normal force from the table on the book is equal to mg. (b) Newton's Second Law says that the...

Hello I have a question just out of curiosity...suppose you set up a delayed choice quantum eraser experiment and the technologies were available to super miniaturize your detectors, and instead of having a single double slit you have several double slit walls set up in alignment that are ultra...

A Cauchy surface is a 3d spacelike slice of spacetime. Could you read the definition (17) p18 the author says that "one can proove that ##\sigma## does not depend on the choice of the Cauchy surface because the functions obey the law of motion." Could you elaborate? Thanks Could anyone add "h"...

Hello I have been looking at the results published by Kim et Al and am a little bit baffled by one of the graphs shown in fig 4. which shows the single detector counting rate of Do. The rate is very approximately constant across the whole range and averages about 280000 counts per second. Very...

Hello everyone, I actually have three questions: 1. Am I missing an important detail in my understanding of how the delayed choice quantum eraser experiment is done? 2. How does one account for what takes place in the experiment without using the concept of "retrocausality" (effect before...

Homework Statement For #5, I added option E, it's the same as B, but the charges are switched around. Homework EquationsThe Attempt at a Solution [/B] 1) Even though A and B look similar, B seems more accurate. The arrows in the corner of A don't seem to point directly to the corner...

Hey, how are you? I would like to know your advice on something which I cannot decide no matter how hard I think about it. I am 19 years old and I am in my first university year in Physics. I live in Argentina, where there is no division between college and school. You choose a career and you...

Homework Statement A wooden cube is floating in water. The upper face of the cube meets the surface of a pool of water when a block with mass 0.200 kg is placed on top of the cube. When you remove the block, there's a 2 cm difference in height between the upper face and the water surface...

Homework Statement Hey, I just need a quick check on these questions. 1) In a regular sound wave, the displacement of the medium is: A. perpendicular to the wave velocity B. sometimes perpendicular and sometimes parallel to the wave velocity C. parallel to the wave velocity. D. neither...

Which of the two books would you pick as an undergraduate engineering student if you were to study the subject of Heat and Mass Transfer entirely on your own? 1. Heat and Mass Transfer: Fundamentals and Applications by Cengel & Ghajar 2. Fundamentals of Heat and Mass Transfer by...

I am interested in studying cosmology or physics during university (as an Australian) and hope that this can lead on to a job further involving cosmology. What are the chances of actually succeeding with this endeavor and is there any chance of employment as an Australian?

Homework Statement There is an optical fiber.A light ray enter it at i°.Total internal reflection occur at X. What are the necessary conditions for the light ray to travel along the core of the fiber? (I have canceled B and D already.) A.n1>n2 and angle i should be greater than a certain value...

on question 20, I think the answer is (A) because wouldn't AD then be perp to BD? In picture 2 question 4 I got (E) because the line should start at -2.5 ,not -3 In picture 2 question 5, I got (B). Seems like maybe a trick question. In picture 3 question 6, I got (C). Is that right? In...

Hi guys. So I've been wondering, what's so controversial about the axiom of choice? I heard it allows the Banach-Tarski Paradox to work. A little insight would be much appreciated, thanks.

The recent thread about the delayed choice experiment made me want to understand the experiment as a quantum circuit. I made this: (contrast with http://www.nature.com/nphys/journal/v8/n6/images/nphys2294-f2.jpg) The left hand side is the qubit-holding wires and gates to apply, with Alice...

Hello everyone, I just received a mail from my university that the planned course "Numerical Methods" has been canceled due to lack of teaching resources. Instead we are offered one of three electice courses and I am not sure what to choose. Perhaps the combined knowledge and experience of PF...

My mind was blown upon discovering this experiment. Subsequent attempts at putting my brain back together have all failed miserably. All posts trying to demystify the experiment have either appeared flawed or were too complex for my primitive liberal arts brain to understand. Now I fear such...

This is a variant associated with the Scully and Druhl signal-idler photon delayed choice experiment, as described and discussed in Brian Greene's Fabric of the Cosmos. The commentary notes the "delay" may be configured to happen a very (years) long time after the photons pass the two...

Hello PF! So I'm an engineering student soon to enter the final year of my degree, and I have two electives that I'm taking physics modules (read: classes for the US peeps :P ). The first one I'm planning on taking Quantum Mechanics I as one of them, but I'm not sure what to take for the other...

I have been mulling over various aspects of delayed quantum erasure and came upon the following puzzle. It is about the famous 'delayed choice quantum eraser' of Kim, Kulik, Shih and Scully. The paper says (1st para of 2nd column on p2) that the path length from the BBO crystal that generates...

Hi guys, I don't know if there's any similar thread (I didn't find any, but in case I missed it); if so please suggest them to me. It's time to apply to college again. I personally think particle physics (experimental) would be my top choice (I understand that only phd has the specialized...

I like maths & also like physics. So can i make career in mech. engineering ? I am not good at programming. So if I wish to take computer engineering, it is good choice ? Please suggest best engineering branches. I'm very confused.

A Delayed Choice Experiment: Sorry, could not resist!

This thread is about my not understanding the conclusion that scientists came to that the photon makes a 'decision' on how to travel. In a simple interferometer experiment, a photon displays interference fringes only when a second beam splitter is present. According to Wiki, this led scientists...

I'm familiar with the delayed choice experiment, and I'm trying to suss out this new setup. http://www.sciencealert.com/reality-doesn-t-exist-until-we-measure-it-quantum-experiment-confirms Reading this article is not very beneficial if there's a confounding typo. Paragraph 10: Should that...

So... I cannot choose a career path. So let's start with the basics i am ok at math and science poor at english. In GCSE i received B in science, C in maths and C in english. I was disappointed as this meant that i could not do A-Level Chem and Bio on college. So now i am doing applied science...

Well... The thing is that I want to improve space travel in the future, so should I be taking Aerospace Engineering or Astrophysics in university? P.S. I am currently in a Polytechnic (aka Community College in USA) studying Aerospace engineering.

At the back of my music keyboard's electric adaptor it says "INPUT: 230V, 50Hz 0.2A OUTPUT: 12V, 1.5A Suppose my adaptor busted and couldn't find the original replacement. Can I use a 9V instead? Will it work? Will it has to be 1.5A then? Power is=I^2 x R as well as I x V, does that mean as...

I'm starting college soon. 2015 Summer Calculus I and Analytic Geometry Pre-calculus and Analytic Geometry Fall Calculus II and Analytic Geometry Calculus I for Life Sciences Linear Algebra United States History I United States History II 2016 Spring Calculus III and Analytic Geometry...

Homework Statement The question says that : Twelve distinct balls are distributes among three distinct boxes. Find the probability that the first box contains 3 balls. Homework Equations None The Attempt at a Solution It can be done through: No. Of choices for each ball=3 Total no. of...

Can anyone please provide me a good link for thermodynamics multiple choice questions? I have seen some,but didn't like them. Thanks.

Hello, I signed up cause I was going through the Quantum Eraser threads, but couldn't find an answer to my question. It's about this version from 1999/2000 of the elaboration on the classic double slit experiment: Results seem quite straight forward. Wherever we have "path information" the...

I'm trying to understand the delayed choice quantum eraser experiment without consciousness. As I understand it, photons will either interfere or not depending on whether or not "which-path" information is randomly hidden and rendered unkowable to the experimenter. That is, rather the by any...

Hi, am a student who studies physics in university. I want to know does laser technology is good choice for career.